Briggs Stratton

SERVICE MANUAL Briggs & Stratton

BRIGGS & STRATTONBRIGGS & STRATTON CORPORATION

Milwaukee, Wisconsin 53201

Model19, 19D,191000,193000

200000

23,23A,23C, 23D,23100,233000

243000

300000,301000

302000

320000

325000

326000

No.Cyls.

1

1

Engines in this section are four-cycle,one cylinder horizontal crankshaftmodels. Crankshaft is supported at eachend in bushing type main bearings whichare an integral part of main bearing sup-port plate or by ball bearings which arepressed onto crankshaft and fit intomachined bores of main bearing supportplates. Cylinder block and crankcase area single cast iron casting.

Connecting rod in all models ridesdirectly on crankpin joumal and issplash lubricated by an oil dipper at-tached to connecting rod cap.

Early models use a variety of magnetoignition systems with points and con-denser either mounted external-ly or underneath flywheel. Late produc-tion models use Briggs & StrattonMagnetron breakerless ignition system.

A float type carburetor is used on allmodels and a fuel pump is available asoptional equipment for some models.

Refer to BRIGGS & STRATTONENGINE IDENTIFICATION INFOR-MATION section for engine identifica-tion and always give engine model andserial number when ordering parts orservice material.

MAINTENANCE

SPARK PLUG. Recommended spark

Bore

3 in.(76.2 mm)

3 in.(76,2 mm)

3 in.(76.2 mm)3.0625 in.

(77.79 mm)

3,4375 in,(87.31 mm)3,4375 in,

(87.31 mm)3.5625 in.(90.5 mm)3.5625 in.(90.5 mm)3.5625 in.(90.5 mm)

Stroke

2.625 in.(66,675 mm)

2.875 in.(73.025 mm)

3.25 in.(82.55 mm)

3,25 in.(82,55 mm)

3,25 in.(82,55 mm)

3,25 in,(82.55 mm)

3.25 in.(82.55 mm)

3.25 in.(82,55 mm)

3,25 in.(82,55 mm)

Displacement

18.56 cu. in.(304.1 cc)

20.32 cu. in.(333 cc)

22.97 cu. in(376.5 cc)

23.94 cu. in.(392.3 cc)

30.16 cu. in.(494.2 cc)

30.16 cu. in,(494,2 cc)

32.4 cu. in.(531 cc)

32.4 cu. in.(531 cc)

32.4 cu. in.(531 cc)

PowerRating

7.25 hp.(5.5 kW)

8hp.(6kW)

9 hp.(6.7 kW)

10 hp.(7.5 kW)

12 hp.(9kW)13 hp,

(9.7 kW)14 hp.

(10.4 kW)15 hp.

(11.2 kW)16 hp.

(11.9 kW)

plug is Champion J8 or equivalent. Todecrease radio interference use Champ-ion XJ8 or equivalent spark plug. Elec-trode gap for all models is 0.030 inch(0.762 mm).

CARBURETOR. All models areequipped With a two-piece float type car-buretor. Refer to Fig, B30 for a cross-sectional view of carburetor and locationof mixture adjustment screws.

For initial carburetor adjustment,open idle mixture screw 1 turn and mainfuel mixture screw IV2 turns.

Make final adjustment with engine atnormal operating temperature and run-

ning. Place engine under load and adjustmain fuel mixture screw for leanest mix-ture that will allow satisfactory ac-celeration and steady governor opera-tion. Set engine idle mixture screw toobtain smoothest idle operation.

As each adjustment affects the other,adjustment procedure may have to berepeated.

To check float level for all models, in-vert carburetor body and float assembly.Refer to Fig. B34 for proper float leveldimensions. Adjust by bending floatlever tang that contacts inlet valve.

Check carburetor for upper body war-page using a 0.002 inch (0.0508 mm)

-THttOTTLf VALVE

Fig. B30'-Cross-sectionalview of typicai two-piecefioat type carburetor. Beforeseparating upper and lowercarburetor bodies, loosenpacking nut and unscrewneedle valve and peckingnut. Use speciai screwdriver,part number 19062 to remove

nozzle.

PUtL IHLET

NCEOCEVALVE

Illustrations courtesy of Briggs & Stratton Corp. 273

Briggs & Stratton GENERATOR

tmn fAifC!/•' fPfi

Fig. 83t — Typical SAS automatic choke unit in''HOT" position.

feeler gage as shown in Fig. B33. If up-per body is warped more than 0.002 inch(0.0508 mm) it should be renewed.

AUTOMATIC CHOKE. A thermostat operated choke is used on somemodels. To adjust choke linkage, holdchoke shaft so thermostat lever is free.At room temperature, stop screw inthermostat collar should be located mid-way between thermostat stops (Fig. B31& B32). If not, loosen stop screw, adjustcollar and tighten stop screw. Loosenset screw (S-Fig. B31) on thermostatlever. Slide lever on shaft to insure freemovement of choke unit. Turn thermo-stat shaft clockwise until stop screw con-tacts thermostat stop. While holdingshaft in this position, move shaft lever

COUITCI CLOCniSC

Fig. B33 — Check carburetor upper body for war-page. If a 0.002 Inch (0.0S08 mm) feeier gage canbe inserted between upper and iower bodies as

shown, renew upper body.

V + 1 "X-32

Fig. B34~ Check carburetor float setting asshown. Bend tang if necessary to adjust fioat

level.

until choke is open exactly Vs-inch (3.18mm) and tighten lever set screw. Turnthermostat shaft counter-clockwise untilstop screw contacts thermostat stop asshown in Fig. B32. Manually open chokevalve until it stops against top of chokelink opening. At this time choke shouldbe open at least 3/32-inch (2.25 mm), butnot more than 5/32-inch (4 mm). Holdchoke valve in wide open position and

check position of counterweight lever.Lever should be in a horizontal positionwith free end towards right.

FUEL PUMP. A diaphragm type fuedpump is available on some models as op-tional equipment. Refer to SERVICIMJBRIGGS & STRATTON ACCES-SORIES section for service informa-tion.

GOVERNOR. All models are equip-ped with a gear driven mechanicalgovernor. Governor weight unit isenclosed within engine and is driven bycamshaft gear. Refer to Fig. B62, Bmor B64 for appropriate exploded view ofmodel being serviced.

To adjust governor, loosen screv^holding governor lever to governorcrank (46-Fig. B62, B63 or B64). Pushgovernor lever as far clockwise as it willgo. Tighten screw holding governorlever to crank until it is snug, but nottight. Push governor lever as farcounter-clockwise as it will go andtighten screw securely.

Governor gear and weight unit can beremoved when engine is disassembled.Remove governor lever, cotter pin andwasher from outer end of governorcrank. Slide crank out of bushingtowards inside of engine. Governor gearand weight unit will then slide off ofshaft. Shaft can be removed from crank-case if necessary. Renew bushing incrankcase for governor crank if bushingis worn and ream new bushing, after in-stallation, to 0.2385-0.239 inch(6.06-6.07 mm).

Refer to Figs. B35 through B38 forgovernor control and carburetor linkagehook-up and adjustments.

Fig. B3S-Views showingmethod of connecting dif-ferent remote governor con-trois. Moving controi ieverwiii vary governor spring ten-sion, thus varying enginegoverned speeds. For viewsshowing remote throttle con-trois, refer to Fig. B36.

Fig. B32—Typical B^S automatic choke in"COLD'' position.

274 Illustrations courtesy of Briggs & Stratton Corp-


Fig. B36-Views showingmethods of connectingremote throttie controis.When controi iever is in highspeed position, governorcontrois speed of engineand governed speed Is ad-justed by turning thumb nut.Moving control lever to slowspeed position moves car-buretor throttie shaft stop todecrease engine speed.

IGNITION SYSTEM. Early modelsuse a variety of magneto type ignitionsystems and late production models useBriggs & Stratton Magnetron ignitionsystem. Refer to appropriate paragraphfor model being serviced.

MODEL 23C MAGNETO. Refer toFig. B39 for exploded view of magnetoused on 23C model engine. Condenser

SPEED ADI . NUTS

and breaker points are mounted oncrankshaft bearing support plate (17)and are accessible after removing fly-wheel and magneto cover (7).

Breaker point gap is 0.020 inch (0.508mm) and condenser capacity is 0.18-0.24mfd.

Breaker point plunger can be removedfrom bore in crankshaft bearing supportwhen breaker points are removed.

Fig. B37— View showing governor linkage,springs and levers properly instaiied on 243000,300000, 301000, 302000, 320000, 325000 and328000 series engines. Refer to Fig. B38 for

remote control hook-up.

Fig. B38—Remote governor control installationon 243000, 300000, 301000, 302000, 320000,

32S0O0 and 328000 series engines.

Plunger should be renewed if worn to alength of 0.870 inch (22.098 mm) or less.Plunger bore diameter may be checkedusing B&S plunger bore gage, partnumber 19055. If gage enters plungerbore V4-inch (6.35 mm) or more, installservice bushing, part number 23513. Toinstall bushing, remove bearing supportfrom engine, then ream bore using B&Sreamer, part number 19056, drivebushing in flush with outer end ofplunger bore with B&S driver, partnumber 19057 and use B&S reamer,part number 19058, to finish ream insideof bushing.

When reinstalling flywheel, inspectthe soft metal key and renew if damagedin any way.

NOTE: Renew key with correct B&Spart. DO NOT substitute a steel key.

After flywheel is installed and retain-ing nut tightened, check armature airgap and adjust as necessary to0.022-0.026 inch (0.5588-0.6604 mm).

MODELS 19, 23 & 23A ANDSERIES 191000 & 231000 MAGNETO.Refer to Fig. B40 for exploded view ofmagneto used on these models.

Condenser and breaker points aremounted externally in a breaker boxlocated on carburetor side of engine andare accessible after removing breakerbox cover (18-Fig. B40).


When renewing breaker points, or ifoil leak is noted, breaker shaft oil seal(16) should be renewed. To renew pointsand/or seal, turn engine so breaker pointgap is at maximum. Remove terminaland breaker spring screws and loosenbreaker arm retaining nut (19) so it isflush with end of shaft (29). Tap loosen-ed nut lightly to free breaker arm (21)from taper on shaft, then removebreaker arm, breaker plate (22), pivot(23), insulating plate (24) and eccentric(17). Pry oil seal out and press new oilseal in with metal side out. Placebreaker plate on insulating plate withdowel on breaker plate entering hole ininsulator. Then, install unit with edgesof plates parallel with breaker box asshown in Fig. B41. Turn breaker shaftclockwise as far as possible and installbreaker arm while holding shaft in thisposition.

Breaker box can be removed withoutremoving points or condenser. Refer toFig. B42. Disassembly of unit is evidentafter removal from engine.

To renew ignition coil, engine flywheelmust be removed. Disconnect coilground and primary wires and pullspark plug wire from hole in back plate.Disengage clips (8-Fig. B40) retainingcoil core (9) to armature (14) and push



core from coil. Insert core in new coilwith rounded side of core towards sparkplug wire. Place coil and core on ar-mature with retainer (7) between coil

and armature. Reinstall core retainingclips, connect coil ground and primarywires and insert spark plug wirethrough hole in back plate.

15 16

1 2 3

7 11 18 17Fig. B39-Expioded view of magneto ignition system used on 23C modei engines. Breaker points andcondenser are mounted on bearing support (i7) and are endosed by cover (7) and fiywheei. Points areactuated by piunger (i3) which rides against breaker cam machined on engine crankshaft.1. Flywheel nut2. Nut retainer3. Starter pulley4. Blower housing5. Flywheel key6. Flywheel

7. Breaker cover8. Spark plug wire9. Breaker point base

10. Breaker point arm11. Breaker spring12. Coil & armature

13. Plunger14. Armature support15. Back plate16. Shim gasket17. Bearing supfx)rt18. Condenser

9 . 10

Fig, B40-Exploded view of magneto ignition system used on 19,23 and 23A models and i9i000 and231000 series engines. Fiywheei is not keyed to crankshaft and may be instailed in any position;however, on crank start modeis, fiywheei shouid be instaiied as shown in Fig. B47. Breaker arm (2i) ismounted on shaft (29) which Is actuated by a csm on engine cam gear. See Fig. B48. Two differentmethods of attaching magneto rotor (5) to engine crankshaft have been used. Refer to Figs, B43 and

B44,1. Starter pulley2. Blower housing3. Flywheel4. Rotor clamp5. Magneto rotor6. Ignition coil7. Coil clip

9.10.U.12.13.14.15.

Coil coreBack plateBearing supportShim gasketRotor keyArmaturePrimary coil knid

16. Shaft seal17. Eccentric18. Breaker IK)X c{)ver1<). Nut20. Washer21. Breaker K̂)int arm22. Breaker iH>int Inise

23.24.25.26.27.28.29.

PivotInsulatorCondenserSeal retainerBreaker IKIXGasketShaft

Two types of magnetic rotors havebeen used. Refer to Fig. B43 for view ofrotor retained by set screw and to Fig.B44 for rotor retained by clamp ring. Ifrotor is as shown in Fig. B44, refer toFig. B45 when installing rotor on crank-shaft.

If armature coil has been loosened orremoved, rotor timing must be read-

^ «— PARALLEL

Fig. B4i — When instaiiing breaker points on 79,23 and 23A modeis and T9T000 and 23i000series engines, be sure dowei on breaker pointbase enters hoie in insuiator. Piace sides ofbase and insuiating piate paraiiei with edge of

breaker box.

Fig, B42- To remove breaker box on f9, 23 and23A modeis and i9i000 and 231000 seriesengines it is not necessary to remove points andcondenser as unit may be removed as an

assembly.

SET SCREW

ROTOR

KEY

Fig. B43 — On some modeis, magneto rotor istfastened to crankshaft by a S9t screw whichenters hoie in shaft. Set screw is iocked inplace

by a second screw. Refer to Fig. B44 aiso.

•

276 Illustrations courtesy of Briggs & Stratton Corp.


\CLAMP WITH CLAMP SCREW. ANO LOCK WASHER

KEY

Ffg. B44-View showing magneto rotor fastenedto crankshaft with ciamp. Make certain spUt inclamp is t>etween two slots in rotor as shownand check ciearance between rotor and shoulder

on crankshaft as shown In Fig. 845.

justed. With point gap adjusted to 0.020inch (0.508 mm), connect a static timinglight from breaker point terminal toground (coil primary wire must bedisconnected) and turn engine in normaldirection of rotation until light goes on.Then, turn engine very slowly in samedirection until light just goes out(breaker points start to open). At thistime, engine model number on magnetorotor should be aligned with arrow onarmature as shown in Fig. B46. If not,loosen armature core retaining capscrews and turn armature in slotted

FEELER CAUCE

lELER CAUCE

Fig. B47- On f 9,23 and 23A modeis and i9iOOOand 23i000 series engines equipped with crankstarter, mount flywheel with pin in position

shown with armature timing marks aligned,

mounting holes so arrow is aligned withappropriate engine model number onrotor. Tighten armature mountingscrews.

To install flywheel on models withcrank starter, place flywheel on crank-shaft as shown in Fig. B47 with magnetotiming marks aligned as in previousparagraph. On models not having acrank starter, flywheel may be installedin any position.

Magneto breaker points are actuatedby a cam on a centrifugal weightmounted on engine camshaft (Fig. B48).When engine is being overhauled, orcam gear is removed, check action of ad-vance spring and centrifugal weight unitby holding cam gear in position shownand pressing weight down. When weightis released, spring should return weightto its original position. If weight doesnot return to its original position, checkweight for binding and renew spring.

MODELS 19D & 23D MAGNETO.Refer to Fig. B49 for exploded view ofmagneto system.

Fig, B45-Modeis having magneto rotorclamped to crankshaft, position rotor 0,025 inch i A A(0.635 mm) from shouider on shaft, then tighten 1 2 3

clamping screw.

Fig. B48-Check timing advance weight andspring on 19,23 and23A models and i9i000 and

23i000 series engines. Refer to text.

Condenser and breaker points aremounted externally in a breaker boxlocated on carburetor side of engine andare accessible after removing cover(8-Fig, B49).


Installation of new breaker points ismade easier by turning engine so pointsare open to their widest gap beforeremoving old points. For method of ad-justing breaker point gap, refer to Fig.B50.

NOTE: When installing points, applyPermatex or equivalent sealer to retainingscrew threads to prevent engine oii fromleaking into breaicer box.

U 15 16 17

13 :•

8 9 10 il 12

Fig. B46-With engine turned so breaker pointsare just starting to open, align model numberiine on rotor with arrow on armature by rotating

armature in slotted mounting holes.

Fig. B49-Exploded view of magneto ignition system used on I9D and 23D models. Magneto rotor(flywheei) to armature timing is adjustabie as shown in Figs. B51 and B52. Adjust breaker points as in

Fig. B50., ^ ^ , 7. Flywheel1. Flywhee nut g. Breaker box cover 14. Coil & armature assy.2. Nutj^tainer 9. Gasket 15. Armature mounting3. Starter pulley 10. Condenser bracket4. Blower housing n . Breaker points 16. Back platea ^^ l ^ lY*""̂ ^2. Breaker spring 17. Bearing support6. Flywheel key 13. Lock nut 18. Shim gasket



Breaker points are actuated by aplunger that rides against breaker camon engine cam gear. Plunger andplunger bushing in crankcase arerenewable after removing cam gear andbreaker points.

Magneto armature and ignition coilare mounted outside engine flywheel.Adjust armature air gap to 0.022-0.026inch (0.5588-0.6604 mm).

If flywheel has been removed,magneto edge gap (armature timing)must be adjusted. With point gap ad-justed to 0.020 inch (0.508 mm) andflywheel loosely installed on crankshaft,install flywheel key leaving retainingcap screw loose. Disconnect magnetoprimary wire and connect test lightacross breaker points. Turn flywheel inclockwise direction until breaker pointsjust start to open (timing light goes out).Now, while making sure enginecrankshaft does not turn, turn flywheelback slightly in counter-clockwise direc-tion so edge of flywheel insert lines upwith edge of armature as shown in Fig.B53. Tighten flywheel key screw, thentighten flywheel retaining nut to110-118 ft.-lbs, (149-160 N-m) torque for19D model and to 138-150 ft.-lbs.(187-203 N-m) torque on 23D model.Readjust armature air gap as necessary.

SERIES 193000, 200000, 233000,243000, 300000, 301000, 302000,320000, 325000 & 326000 MAGNETO.Refer to Fig. 54 for exploded view ofmagneto system.

Condenser and breaker points aremounted externally in a breaker boxlocated on carburetor side of engine andare accessible after removing cover(8-Fig. B54).

Breaker point gap is 0.020 inch (0.508mm) and condenser capacity is 0,18-0.24mfd.

Installation of new breaker points ismade easier by turning engine so points

FLYWHEELINSERT

TURN BREAKERPOINT SCREWCLCXKWISETO INCREASE

GAP

WASHER

,020"GAP

CONDENSER

Fig. B50- On aii modeis equipped with this typeof breaker points, ioosen iock nut and turn ad-justing screw to obtain 0,020 inch (0.508 mm)

gap.

Fig. B5i-0n i9D and 23pmodeis, magneto timing isadjusted by repositioningfiywheel on crankshaft,Flywheei is then iocked intoproper position by tighten-ing key screw and flywheelretaining nut. Refer aiso to

Figs. B52 and B53.

Fig. B52- Turning engine innormai direction of rotationwith flywheel and flywheeikey ioose. Turn engine siow-iy untii breaker points arejust starting to open. Referto text and Figs. B51 and

B5X

Fig. B53-Turn fiywheeicounter-clockwise on crank-shaft until edge of flywheeiinsert is aiigned with edge ofarmature as shown in insert.Then, tighten fiywheei key

screw and retaining nut.

6 8 9 10 11 12Fig, B54-Expioded view of i93000, 200000, 233iHiO and 243000 series magneto ignition system.Magneto used on 300000,301000, 302000, 320000, i25000 and 326000 series is simiiar. Position of ar-mature is adjustabie to time armature with magnsto rotor (flywheel) by moving armature mounting

bracket (15) on slotted mounting holeti. Refer to text and Figs. 855 and B56,1. Flywheel nut 8. Breaker box cover 14. Coil & armature assy.

9. Gasket 15. Armature mounting2. Nut retainer3. Starter pulley4. Blower housing6. Flywheel key7. Flywheel

10. Condenser11. Breaker points12. Breaker spring13. Lock nut

bracket16. Back plate17. Bearing support18. Shim gasket

278 Illustrations courtesy of Briggs & Stratton Coip.


ARMATURE

ALIGNMENT ARROWS

Fig. BBS-On 193000, 200000, 233000, 243000,300000, 301000, 302000, 320000, 325000 and32$000 series, time magneto by aiigning ar-mature core support so arrow on support isaiigned with arrow on flywheel when breakerpoints are just starting to open. Refer to text for

procedure.

are open to their widest gap beforeremoving old points. For method of ad-justing breaker point gap, refer to Fig.B50.

NOTE: When installing points, appiyPermatex or equivaient sealer to retainingscrew threads to prevent engine oii fromieaking into breaicer box.

Breaker points are actuated by aplunger that rides against breaker camon engine cam gear. Plunger (43-Fig.B62) and plunger bushing (PB) arerenewable after removing engine camgear and breaker points. On 300000,301000, 302000, 320000, 325000 and326000 series engines breaker plungerand plunger bushing are similar to thoseshown in Fig. B62.

Magneto armature and ignition coilare mounted outside engine flywheel.Adjust armature air gap to 0.010-0.014inch (0.254-0.3556 mm).

If flywheel has been removed,magneto edge gap (armature timing)must be adjusted. With point gap ad-

ARMATURE MOUNTINGBRACKET

MOUNTING SCREWSFig. BS$~Vi0w with fiywheei removed on193000, 200000, 233000, 243000, 300000, 301000,302000, 320000, 325000 and 326000 seriesengines. Magneto Is timed by shifting armaturemounting bracket on siotted mounting holes.

Refer to Fig. B55 aiso.

MOUNTINGBRACKET

Fig. B57~ After mountingbracket is properly instaiied(Fig. B56k Install armatureand coii assembiy so thereis a 0.010-0.014 inch(0.254-0.35S6 mm} air gapbetween armature and

fiywheei.

justed to 0.020 inch (0.508 mm) and ar-mature ignition coil assembly removedfrom bracket connect a test light acrossbreaker points. Disconnect coil primarywire and slowly turn flywheel in aclockwise direction until light just goesout (breaker points start to open). Atthis time, arrow on flywheel should beexactly aligned with arrow on armaturemounting bracket (Fig. B55). If not,mark position of bracket, removeflywheel and shift bracket on slottedmounting holes (Fig. B56) to bring ar-rows into alignment.

Reinstall flywheel, make certain ar-rows are aligned and tighten flywheelnut to 110-118 ft.-lbs. (149-160 N-m) tor-que on 193000 and 200000 seriesengines and 138-150 ft.-lbs. (187-203N-m) torque on all remaining models.Readjust armature air gap as necessary.

MAGNETRON IGNITION. Magne-tron ignition is a self-containedbreakerless ignition system. Flywheeldoes not need to be removed except tochange timing by moving armaturebracket or to service crankshaft key orkeyway.

.010" - .014"AIR GAP

To check spark, remove spark plugand connect spark plug cable to B&Stester, part number 19051 and groundremaining tester lead to engine cylinderhead. Spin engine at 350 rpm or more. Ifspark jumps the 0.166 inch (4.2 mm)tester gap, system is functioning proper-ly.

To remove armature and Magnetronmodule, remove flywheel shroud and ar-mature retaining screws. Use a3/16-inch diameter pin punch to releasestop switch wire from module. Toremove module, unsolder wires, pushmodule retainer away from laminationsand push module off. See Fig. B57A.

Resolder wires for reinstallation anduse Permatex or equivalent gasket seal-er to hold ground wires in position.

To set timing for gasoline fuel opera-tion, install armature bracket so moun-ting screws are centered in slots (Fig.B57B).

To set timing for kerosene fuel opera-tion, install armature bracket as far toleft as possible (Fig. B57B).

Adjust a rmature air gap to0.010-0.014 inch (0.25-0.36 mm).

Fig. B57A-Wires must beunsoidered to remove

Magnetron module.



IGNITION ARMATUREWITH MAGNETRON"MOOULE ASSEMBLY

MOUNTINGSCREWS

"CENTERED"

IGNITION ARMATUREWITH "MAGNETRON"MOOULE ASSEMBLY

MOUNTINGSCREWSTO FARLEFT"

Fig. B57B-Upper viewshows position of armaturebracket for gasoline fuelsand iower view shows posi-tion of armature bracket forkerosene fuels for correct ig-

nition timing.

LUBRICATION. All models aresplash lubricated by an oil dipper attach-ed to connecting rod.

Oils approved by manufacturer mustmeet requirements of API service clas-sification SE or SF.

Use SAE lOW-40 oil for temperaturesabove 20*̂ F (-7° C) and SAE 5W-30 oilfor temperatures below 20° F (-7° C).

Check oil level at five hour intervalsand maintain at bottom edge of fillerplug. DO NOT overfill.

Recommended oil change interval forall models is every 25 hours of normaloperation.

Crankcase oil capacity for 18.56 and20.32 cubic inch models is 3 pints (1.4 L)and crankcase oil capacity for all re-maining models is 4 pints (1.9 L).

REPAIRS

CYLINDER HEAD. When removingcylinder head note location from whichdifferent cap screws are removed asthey must be reinstalled in their originalpositions.

Always use a new gasket whenreinstalling cylinder head. Do not usesealer on gasket. Lubricate cylinderhead bolt threads with graphite grease,install in correct locations and tighten inseveral even steps in sequence shown inFig. B58 according to type head used.Tighten cap screws to 190 in.-lbs. (22N*m) torque. Start and run engine untilnormal operating temperature is reach-ed, stop engine and retighten head boltsas outlined.

Fig. B58-View of two dif-ferent cylinder heads used.Tighten cylinder head capscrews in sequence shownto 190 in.lbs. (22 N-m) tor-que. Refer to text for tighten-

ing procedure.

^ CAM GEAR SIDE

FLAT

Fig. B59—Drawing of iower end of connectingrod showing ciearance fiat and assembly marks.

It is recommended carbon and leacideposits be removed at 100 to 300 hourintervals, or whenever cylinder head isremoved.

CONNECTING ROD. Connecting rodand piston are removed from cylindei:*head end of block as an assembly.Aluminum alloy connecting rod ridesdirectly on induction hardened crank-shaft crankpin journal. Rod should b<?renewed if crankpin bore is scored orout-of-round more than 0.0007 inch(0.0178 mm) or if piston pin bore isscored or out-of-round more than 0.0005inch (0.0127 mm).

Model19, 19D190000

200000

23, 23A,23C, 23D,230000

240000

300000,320000

REJECT SIZES FORCONNECTING ROD

Crankpinbore

1.001 in.(25.43 mm)

1.127 in.(28.63 mm)

1.189 in.(30.20 mm)

1.314 in.(33.38 mm)

Pin bore*

0.674 in.(17.12 mm)

0.674 in.(17.12 mm)

0.736 in.(18.69 mm)

0.674 in.(17.12 mm)

1.314 in. 0.802 in.(33.38 mm) (20.37 mm)

*Piston pins of 0.005 inch (0.127 mm)oversize are available for service.Piston pin bore in rod can be reamed tothis size if crankpin Jbore is withinspecification.

Connecting rod running clearance tocrankpin is 0.0015-0.0045 inch (0.0381-0.1143 mm) and piston pin to rod pinbore clearance is 0.0005-0.0015 inch(0.0127-0.0381 mm).

On 300000, 301000, 302000, 320000,325000 or 326000 series engines, notchon top of piston and letter "F" on sideof piston must be on the same side asassembly marks on connecting rod


SERVICE MANUAL

MOTCH

ASSEMBLY MARKS FLYWHEEL SIDE

Fig. B60-On 300000, 301000, 302000, 320000,325000 and 326000 series, assembie piston toconnecting rod with notch and stamped ietter"F" on piston to same side as assembiy markson rod. Install assembiy In cylinder withassembly marks to fiywheei side of crankcase.

(Fig. B60). Install assembly in cylinderwith assembly marks to flywheel sideof crankcase.

On all remaining models connectingrod position in crankcase is determinedby clearance flat on rod as shown inFig. B59. Assemble cap to rod bymatching assembly marks.

Tighten connecting rod cap screwson all models to 190 in.-lbs. (22 N-m)torque.

END PLAY . 0 0 2 " - . 0 0 8 "

Fig. B61 — Crankshaft end play can be checkedas shown on models with main bearings whichare an integrai part of bearing support plates.

PISTON, PIN AND RINGS. Alumi-num alloy piston has two compressionand one oil control ring and pistonshould be renewed if top ring sideclearance in groove exceeds 0.007 inch(0.178 mm) or if piston is visibly scoredor damaged. Piston should also berenewed or pin bore reamed for 0.005inch (0.127 mm) oversize pin if pin boreis worn to, or greater than rejectiondiameter shown in chart.

PISTON PIN BOREREJECTION SIZES

Model Pin bore19, 19D, 191000, 193000,

200000,243000 0.673 in.(17.09 mm)

Briggs & Stratton

23, 23A, 23C, 23D,231000,233000 0,736 in,

(18.69 mm)300000, 301000, 302000,

320000, 325000,326000 . . . 0.801 in.(20.35 mm)

Renew piston pin if pin is 0.0005 inch(0.0127 mm) out-of-round or if pin isworn to, or below, rejection diametershown in chart.

PISTON PIN REJECTION SIZESModel Pin diameter19, 19D, 191000, 193000,

200000,243000 0.671 in.(17.04 mm)

23, 23A, 23C, 23D,231000, 233000 0.734 in.

(18.64 m m )300000, 301,000, 302,000,320000, 325000, 326000 0.799 in.

(20,30 m m )

Ring end gap should be 0.010-0.025 inch (0,245-0,635 mm) and com-pression ring should be renewed if endgap is greater than 0.030 inch (0.75mm). Oil control ring should be renewedif end gap is greater than 0,035 inch(0.90 mm).

Pistons used in 300000, 301000,302000, 320000, 325000 and 326000series engines have a notch and a letter"F" stamped in piston (Fig. B60) which

19.20.21.22.23.24.25.26.27.

28.29.

30.31.32.33.34.35.36.37.38.39.

40.41.42.43.44.

45.46.47.48.49.50.51.52.

53.54.55.56.

57.58.59.

Spark plug

Cylinder headGasketBreather tubeBreatherMain bearing plateGasketEngine crankcase &cylinder blockGovernor shaftGovernor gear &weight unitCamshaftCam gearTappetsCamshaft plugEngine baseGasketValvesValve spring washersValve springsSpring retainers or"Roto-Caps"KeepersGasketTappet chamber coverBreaker point plungerGovernor controlleverGovernor springGovernor crankGovernor control rodGovernor linkGovernor leverOutput drive keyCrankshaftBall bearings (onmodels so equipped)Oil dipperRod bolt lockConnecting rodPiston pin retainingringsPiston pinPistonPiston rings

21 20 19

47

Fig. B62—Exploded view of typical 19D, 23D, 193000, 2(H>000, 233000 and 243000 engines. Breaker piunger bushing (PB) and governor crank bushing (GB}in engine crankcase (27) are renewable. Breaker piunger (43) rides against a lobe on cam gear (31),


Briggs & Stratton

must face flywheel side of engine afterinstallation.

Pistons and rings are available in avariety of oversizes as well as standard.

CYLINDER. Standard cylinder borediameters are listed in following chart.

STANDARD CYLINDERB O R E SIZES

Model Standard bore19, 19D, 191000, 193000,23, 23A, 230, 23D, 200000231000, 233000 2.999-3.000 in.

(76.18-76.23 m m )243000 3.0615-3.0625 in.

(76.79-76.82 m m )300000, 301000,302000 3.4365-3.4375 in.

(87.287-87.313 m m )320000, 325000,326000 3.5615-3.5625 in.

(90.462-90.488 m m )

If cylinder is worn 0.003 inch (0.076mm) or more, or out-of-round 0.0025inch (0.0635 mm) or more, it should beresized to nearest oversize for whichpiston and rings are available.

NOTE: A chrome piston ring set is

availabie for siightiy worn standard bore

cylinders. No honing or cyiinder degiazing

is required for these rings. Cyiinder bore

can be a maximum of 0.005 inch (0.127

mm) oversize when using chrome rings.

CRANKSHAFT AND MAIN BEAR-INGS. Crankshaft may be supported ateach end in main bearings which are anintegral part of crankcase and sump orball bearing mains which are a press fiton crankshaft and fit into machinedbores in main bearing support plates.

Crankshaft for models with mainbearings as an integral part of mainbearing support plates should be renew-ed or reground if journals are out-of-round 0.0007 inch (0.0178 mm) or moreor if main bearing journals are worn to adiameter of 1,179 inch (29.95 mm) orless for 19, 19D models and 191000,193000 and 200000 series engines or1.3759 inch (34.95 mm) or less for 23,23A, 23C, 23D models and 231000 and233000 series engines.

Crankshaft for models with ball bear-ing main bearings should be renewed if

GENERATOR

new bearings are loose on journals.Bearings should be a press fit.

Crankshaft for all models should berenewed or reground if connecting rodcrankpin journal diameter is worn to, orbeyond crankshaft rejection specifica-tions as listed in following chart.

CRANKSHAFTREJECTION SIZES

Model Crankpin journal19,19D, 190000,193000 0.996 in.

(25.30 m m )200000 1.122 in.

(28.5 m m )23, 23A, 23C, 23D, 230000 .... 1.184 in.

(30.07 m m )243000, 300000, 301000,302000, 320000, 325000,326000 1.309 in.

(33.25 m m )

Connecting rod is available forcrankshaft which has had connectingrod crankpin journal reground to 0.020inch (0.508 mm) undersize.

Crankshaft main bearing supportplates should be renewed if integral type

21 20 1923 36

24

48

30

Fig. B63-^xpioded view of typicai modei 19, 23, 23A, 191000 and 231000 engines equipped with "Magna-Matic" ignition system; note ignition advanceweight (A W). Refer to Fig. B40 for ignition system.

AW.19.20.21.22.23.24.25.

^5H.

Advance weightSpark pluÂir baffleCylinder headHeJwJ ^LsketBreather tulK>BreatherHearing plate (plaintuishin^)Bearing plate (\v.i\\In-urin^)

2H. Cuisket27. F^n^ne ixankca.^' &

cylin(ier l)l(H'k28. (fovernor shaft21 >. (Governor êar &

weight unit3(», Camshaft31. Cum êar32. TapfH'ts33. ('amshaft plu^

34.35.3fi.37.

38.39.

40.41.

Knj^ne baseGiwketValvesValve spring;washersValve springesS|irinjj retainers or"Roto-('aps"KeefHTS(IjLsket

42.

44.

45.4(i.47.

48.49.

TapjH't chamUrcovCio\

lev(K)\

(tO\(rt)\

rcMi

(IO^

()o\

er'ernor control

erntvr spring;ernor crankernor control

iTnor link•ernor lever

50.51.52.

53.54.55.5(i.57.58.51>.

Ou tpu t dr ive ke>CrankshaftBall U'arin^rs (onnKMk'ls so e(iiiip(Oil (iipjKTKtMl lH)lt l(K-k(înntH'tinjj nxlRi'Uiininj; rinp*I*isU)n pinPistonFîston rinjrs



36 35 34 33

54 53 42Fig. B64 - Expioded view of typical 300000, 30i000, 302000,320000, 325000 and 326000 engines. Balance weights, ball bearings and cover assemblies (2

1. Oil seal2. Cover & balance assy,

(pto end)3. (iasket4. "E" ring5. Idler gear6. Bearing support plate7. Cylinder block8. Head gasket9. Cylinder head

10. Spark plug11. Valves

and Z4) are serviced only as assemblies.23. Gasket

12. Spring caps 24. Cover & balance assy.13. Valve springs (nriagneto end)14. Spring retainer or 25. Oil se^

rotator 26. Retaining rings15. Keepers 27. Piston pin16. Breather assy. 28. Piston rings17. Breather tube 29. Piston18. Idler gear 30. Connecting rod19. "E" ring 31. Oil dipper20. Shim 32. Rod bolt lock21. Cam bearing 33. Ball bearing22. Balancer drive gear 34. Crankshaft

35. Key36. Ball bearing37. Drive gear bolt38. Belleville washer39. Govemor control

lever40. Bearing support plate41. Shim42. Control rod43. Link44. Governor lever45. Govemor springs

46. (Governor crank assy.47. Gasket48. Engine base49. Valve lifters50. Govemor gear &

weight unit51. Govemor shaft52. Cam gear53. Camshaft54. Balancer drive gear55. Belleville washer56. Drive gear bolt

main bearing bores are 0.0007 inch(0.0178 mm) or more out-of-round or ifbearing bore diameter is 1.185 inches(30.1 mm) or more for 19,19D models or191000, 193000 and 200000 seriesengines, 1.382 inches (34.1 mm) or morefor 23, 23A, 23C, 23D models or 243000,300000, 301000, 302000,320000, 325000and 326000 series engines. No servicebushings for main bearings are avail-able.

Ball bearing mains are a press fit oncrankshaft and must be removed bypressing crankshaft out of bearing.Renew ball bearing if worn or rough.Expand new bearing by heating in oiland install on crankshaft with shield sidetowards crankpin journal.

Crankshaft end play should be0.002-0.008 inch (0.0508-0.2032 mm)and is adjusted by varying thickness ofgaskets between flywheel main bearingsupport plate and crankcase. Gasketsare available in a variety of thicknesses.

When reinstalling crankshaft, makecertain timing marks are aligned (Fig.B66 or B67).

CAM GEAR AND CAMSHAFT. On19, 19D, 23, 23A, 23C, 23D models or

191000, 193000, 200000, 233000 and243000 series engines timing gear andcamshaft lobes are cast as an integralpart and are referred to as a "cam gear".Cam gear turns on a stationary shaft re-ferred to as a "camshaft". Reject cam-shaft if it is worn to, or less than, adiameter of 0.4968 inch (12.62 mm).

On all remaining models cam gear andlobes are an integral part referred to asa "cam gear". Camshaft (53-Fig. B64)rotates with cam gear (52). Camshaftrides in a bearing in cylinder block onpto end of engine and journal on cam-gear rides in renewable cam bearing (21)

on magneto end of engine.Renew camshaft if worn to 0.6145

inch (15.6 mm) or less and renew camgear (52) if journal diameter is 0.8105inch (20.6 mm) or less or if lobes areworn to a diameter of 1.184 inches (30.1mm) or less for 300000, 301000 and302000 series engines or 1.215 inches(30.9 mm) or less for 320000,325000 and326000 series engines.

When installing cam gear in 300000,301000, 302000, 320000, 325000 and326000 series engines, cam gear endplay should be 0.002-0.008 inch(0.0508-0.2032 mm) and is controlled by

Fig, B6S — Synchro-Balanceweights rotate in oppositedirection of crankshaftcounterweights on 300000,30i000, 302000, 320000,325000 and 326000 series

engines.

A B CLllustrations courtesy of Briggs & Stratton Corp. 283


using different thickness shims (20) bet-ween cam gear bearing (21) andcrankcase. Shims are available in avariety of thicknesses. Tighten cam gearbearing cap screws to 85 in.-lbs. (10N*m) torque.

On models with "Magna-Matic" igni-tion system, cam gear is equipped withan ignition advance weight (AW-Fig.B63). A tang on advance weight con-tacts breaker shaft lever (29-Fig. B40)each camshaft revolution. On all othermodels, breaker plunger rides against alobe on cam gear.

On models with "Easy-Spin" startingintake cam lobe is machined to hold in-take valve slightly open during part ofcompression stroke, thereby relievingcompression and making engine easierto start due to increased cranking speed.

NOTE: To check compression onmodels with "Easy-Spin" starting, enginemust be turned bacicwards.

"Easy-Spin" cam gears can be identi-fied by two holes drilled in web of gear.If part number of older cam gear and"Easy-Spin" cam gear are the same ex-cept for an "E" following new partnumber, gears are interchangeable.

On all models, align timing marks oncrankshaft gear and cam gear whenreassembling engine.

GOVERNOR WEIGHT UNIT. Tangson governor weights should be squareand smooth and weights should operatefreely. If not, renew gear and weightassembly (29-Figs. B62 and B63) or(50-Fig. B64). Renew governor shaft ifworn or scored.

GOVERNOR CRANK. With gover-nor weight and gear unit removed,

AND BELLEVILLE WASHERTORQUE 700 IN.-LBV

V S ^ I V E CEAR

\ \ IDLER GEAR

Fig. B66—View showing baiancer drive gear(magneto end) being timed. With piston at TDC,insert i/4'inch (6.35 mm) rod through timing hoie

in crankshaft bearing support plate.

Fig, B67— View showing balancer drive gear onpto end of crankshaft being timed. With pistonat TDC, insert 1/4-inch (6,35 mm) rod through tim-ing hoie in gear and into iocating hoie in

crankshaft bearing support piate.

remove and inspect governor crank;renew if worn, (governor crank shouldbe free fit in bushing in engine crankcasewith minimum bushing to crank clear-ance. Renew bushing if new crank fitsloosely. Bushing should be finish reamedto 0.2385-0.239 inch (6.0579-6.0706 mm)after installation.

VALVE SYSTEM. All models areequipped with renewable exhaust valveseat inserts and intake valve seats aremachined directly into cylinder block.Seats are ground at a 45° angle and seatwidth should be 3/64 to 1/16-inch (1.2 to1.6 mm). Service exhaust and intakevalve seat inserts are available and areinstalled using special tools availablefrom Briggs & Stratton.

Valve face is ground at a 45° angleand valve should be renewed if margin is1/64-inch (0.4 mm) or less after refacing.

Valve guides should be checked forwear using valve guide gage number19151. If gage enters valve guide5/16-inch (7.9 mm) or more, guidesshould be reamed using reamer number19183 and bushing number 19192 shouldbe installed.

Briggs & Stratton also had a tool kit,part number 19232, available for remov-

Fig. B68 —Insert f/8-/nc/i(3.19 mm) rod through timinghole in covers and into hoiein balance weights when in-staiiing cover assembiies.

Piston must be at TDC,

ing factory or field installed guidebushings so new bushing, part number231218 may be installed.

Valve tappet gap (cold) for 19, 19Dmodels or 191000, 193000 and 200000series engines is 0.007-0.009 inch(0.18-0.23 mm) for intake valves and0.014-0.016 inch (0.36-0.41 mm) for ex-haust valves.

Valve tappet gap (cold) for all othermodels is 0.007-0.009 inch (0.18-0.23mm) for intake valves and 0.17-0.19 inch(0.43-0.48 mm) for exhaust valves.

To adjust valves, piston must be at"top dead center" on compressionstroke. Grind end of valve stem offsquarely to obtain clearance.

SYNCHRO-BALANCER. 300000,301000, 302000, 320000, 325000 and326000 series engines are equipped withrotating balance weights at each end ofcrankshaft. Balancers are geared torotate in opposite direction ofcrankshaft counterweights (Fig. B6Ei).Balance weights, ball bearings andcovers (2 and 24 - Fig. B64) are servicedas assemblies only.

Balancers are driven from idler geai-s(5 and 18) which are driven by gears (22and 54). Drive gears (22 and 54) arebolted to camshaft. To time balancers,first remove cover and balancerassemblies (2 and 24). Position piston atTDC. Loosen bolts (37 and 56) untildrive gears will rotate on cam gear andcamshaft. Insert a V4-inch (6.35 mm) rodthrough timing hole in each drive gearand into locating holes in main bearingsupport plates as shown in Figs. B66and B67. With piston at TDC and V4-inc h(6.35 mm) rods in place, tighten dri\̂ egear bolts to a torque of 200 in.-lbs. (23N-m). Remove V4-inch (6.35 mm) rods.Remove timing hole screws (Fig. B63)and insert Vs-inch (3.18 mm) rodsthrough timing holes and into hole inbalance weights. Then, with piston atTDC, carefully slide cover assemblies in-to position. Tighten cap screws in ptoend cover to 200 in.-lbs. (23 N-m) torqueand tighten magneto end cover capscrews to 120 in.-lbs. (14 N'm) torque.Remove Vs-inch (3.18 mm) rods. Coatthreads of timing hole screws with Per-matex or equivalent and install screwswith fiber sealing washers.

284 Illustrations courtesy of Briggs & Stratton Co rp.

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