FOREST FIRE RESEARCH INSTITUTE

Canadian F~restry Service

Department of Fisheries and Forestry

PERFORMANCE TESTS ON

GORMAN-RUPP BACKPACK

PORTABLE FOREST FIRE PUMP

G. S. Ramsey, D. Higgins P. Lavigne

This isa Special Report prepared for The Associate Committee on Forest Fire Protection of the National

Reseapch Council. It should not be cited as a reference op peppoduced in whole or in papt without written

consent of the Committee.

Ottawa

TABLE OF CONTENTS

Page

List of Illustrations •..•.•.....••................•......•... .' •••.....•. (if) Introduction ............................................................ 1 General description ...•.••....••.....•.......•••.•...•••...•••...••..•.. 2' General examination..................................................... 2

(a) Weight of. pumping unit and accessories ....................... ', 2 (b) Dimensions of pumping unit ............•...•....••.••..•••••.. 3: (c) Pumping ·unit protrusions ...................................... 3' (d) Arrangements for carrying and back-packing .••.••..•. , ...•.••.. 3 (e) Adequacy of nameplate instructions'............................ 3 (f) Conformity to plans, specifications and manuals •......•....... 3'

Orientation Tests (Unit "AIf) ................ 0.' •••••••••••• ~. I •••••••••• • 6' (a) Horizontal test ................. ; .... 00' ....................... , 6 (b) Tilt test ..••......•..........•••....•..•• ,.................... 6'

Shut-off test (Unit nAn) ............•.••...•..•...•.•...•..•..•..••..... 6' Performance test at minimum suction lift (Unit "A") ..................... 6 Suction lift performance test (Unit IIA") ................................ 7 Series (tandem) operation (Units HA" and "B") ............................ 7 Hydrostatic test (Unit nAn) ......•.....••....••....••••.•..•••..•••.•.•• 7 Muddy water test (Unit "A") .......•.•..•.....•.......••.............•.•• 9' Performance at 5' suction lift before and after muddy water test.

, (Unit nAn) ..••...•.••.. , .•••........ : .......• " •••...••...••....••.• 9 Disassembly examination (Unit "A") ...................................... 9' uiiit: "A" adjustments, repairs and replacements .......................... 13 200 hour endurance test (Unit liB") ...................................... 13 Performance at 5' suction lift before and after endurance test (Unit liB") 15 Disassembly examination (Unit nBn) ............................... ; ...... 15 Operation record before endurance test (Unit nBn) ............••.....•... 16' Endurance test operation record (Unit "BII) .................••....••..••• 16 Operation record after endurance test (Unit "BII) ...••......•.......•.•.. 20 Appendix No.1 ...................................... ! ................... .

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List of Illustrations

Photo No.

Instrument pane l ........................................................ 1 Ca:rrier transporting Gorman-Rupp Backpack pwnp .......................... 2 Fuel inlet and control side of Gorman-Rupp Backpack pwnp ................ 3 Exhaust side of Gorman-Rupp Backpack pwnp ............................... 4 Appa:ratus for measuring fuel conswnption ................................ .5 Series (tandem) operation set-up ......................................... 6 Carbon sealing washers ...•............................................... 7

\ ·Irnpe Z ZeT's ............................................................... 8 Volute ....................................... : ........ .................. 9 Endurance test set-up ................................... ;'............... 10

Figure No.

Unit· "A" performance at minimum suction lift ................•..••••.•.•• 1 Unit "A" performance at· varied"suction lift............................. 2 Unit "A" performance at 5 ft. suction 1iJ;t before and after muddy

water test .......................................................... 3 Unit "B" performance at 5 ft. suction lift before and after

endurance test .. ' ................ ' ............... ,I' . . . . . . . . . . . .. . . . .. 4

Appendix No.

Comparison between equivalent and actual suction lift ................... 1

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Intruduction

Performance Tests on Gorman-Rupp Backpack Pump

Portable Forestry Fire Pump

During the summer of 1968 the Forest Fire Research Institute of 'the Canada, Dept. of Forestry and Rural Development conducted a series of performance and endurance tests on two Gorman-Rupp Backpack fire pumps. The tests, at the request of the National Research Councils' Associate Committee on Forest Fire Protection, were undertaken in compliance with the Canadian Government Specification Board specification, Standard Methods of Test for PortabZe Forestry Fire Pwnps, 28-GP-5, dated February 14, 1964.

Mr." G. W. shdrter, Head, Fire .Section, Division of Building Research~ N.R.C., very kindly made arrangements for the transfer to the,Institute of the instrumentation. used on-previous tests in this ser.ies. Thus, the same basic

') conditions and equipment were used on this test as on earlier ones. (Photo No.1) As mentioned in 28-GP-5, Section 13, other tests may be included in the 'test program as deemed useful. Thus, additional instrumentation was installed.and measurements obtained during the tests which will be used in other research projects of the Institute dealing with fire pump operation.

The specification covers procedures for conducting type and qu~lifi­cation tests .on portable forestry fire pumps, powered by internal combustion englnes. It is the intent of these methods of test that the Laboratory make such minor adju~tments, repairs and replacements as may oe needed to complete. the whole series of tests rather than discontinue the tests at the first malfunction or failure.

The CGSB Standard Methods of Test for PortabZe Forestry Fire Pumps, 28-GP-5 specifies that: "the fuel shall contain 2.5t 0.2 mI. Tetraethyl lead per Imperial gallon. It The intention of this requirement was to insure uniform~_ty in tests made at various times with different kinds of fuel. The basic characteristics of gasoline vary greatly depending on the particular. crude oil feedstock used at the refinery to produce the gasoline. The addition of this specified amount Tetraethyl lead would mask any difference in the basic fuel.

When arrangements were being made to purchase fuel for the test, no Oil Company could offer any that would exactly meet this .requirement from their normal supplies, on a continuing basis. The Shell Oil Company refinery staff were most helpful in this regard. They pointed out that the specification as written could be met by adding the required Tetraethyl lead to ordinary diesel fuel but felt this would not be' a satisfactory pump fuel. They offered to supply an unleaded naptha as a base fuel, which they···could blend for repeat orders to a standard

, ' 0 quality. This would have a vapour :pressure range of 6.5, a boiling range of 124 -238°F, with a specific gravity of 66.5° API and a consistent low gum content. To this they would add the required 2.5 ml Tetraethyl. Although meeting the specifi­cations) this fuel would not be typical of that used in most pu~ps.

The so called "regular" automotive gasolines sold in the Ottawa area have a Tetraethyl lead content in the 2 to 3 ml range. Thanks to the cooperation of Dr. R.B. Whyte of the fuels and Lubricants Laboratory, National Research Council, a number of samples of commercially available gasoline were checked. One was with­in the required Tetraethyl lead range. A q'!antity of this, sufficient for the test,

1

was purchased and a further sample tested by the Fuels and Lubricants Laboratory. The gasoline used had a vapour pressure of 10.7; boiling range 820

- 335+oF; existent gum, 1.6 mg/100 ml; and a lead content of 2.65 ml/Imperial gallon. To this was added Esso Outboard Oil. in the quantity recommended by the manufacturer.

Before future tests are made, it might be advisable to'review the section of eGSB 28-GP-5 relating to fuel. Normally, "regular" gasoline is used under field conditions and this is readily available. Unless more rigid specifications are included to cover such points as gum content and vapour pressure, this might be a , satisfactory fuel to use for tests.

Two pump units for testing, complete with accessories were submitted -by the Ottawa River Forest Protective Association to the Forest Fire Research Institute Hydrau~ics Laboratory situated on the Petawawa Forest Experiment Station, Chalk River, Ontario.

Prior to testing, representatives of Gorman-Rupp of Canada Limited; S"'t. Thomas, Ontario, were invited to view the test fCi;cilities and perform initial minor adjustments on the ~'!,mits. They were present during th.e shut-off test and part of the orientation tests-.

General Description

The type of pump submitted can be described as a Gorman-Rupp.Backpack pump, Model 61-1/2 DP. (Photo No. 's 3 & 4) It, is equipped with a single-stage centrifugal pump'powered by a West Bend, single-cylinder, 8 HP, two-cycle, air­cooled eng~ne. ' Rubber vibration mounts secure the unit to a tubular base frame. Both suction and discharge connections are 1 1/2 inch Standard Hose Connections compatable with CSA Standard B 89. Choices 9f fuel tanks (with fuel hose and quick connector) are as follows: 4 Imperial gallons backpacking fuel. tank, including carrying straps (furnished as standard equipment unless otherwise specified), 2 Impert'al gallons backpacking fuel tank, including carrying. straps or 3.5 Imperial gallons, side carry, fuel caddy. The 4-ga1lon tank was supplied for these tests.

The units were designated a; IiAIi and liB" unit and the report w~ll distinguish between them in this manner.

General Examination (Unit "AIt)

Unit "A" plus major accessories was examined as to weight, dimensions," conformity to plans etc.

(a) Weight of pumping unit and accessories

Dry pumping unit Suction hose (10') Foot valve and strainer 2" suction adapter Backpac~·Pu¢p .harness Fuel tank (in~luding fuel line and

carrying straps) Protective U-bar and carrying handle Field tool kit (Knock-off nut, spark plug

wrench, etc.)

Total

2

29 1b 8 1/2 oz. 12 lb 4 1/2 oz.

1 lb 8 1/2 oz. 6 oz.

2 lb 1 oz.

8 lb 4 oz. 1 lb 3 1/2 oZ'.

8 oz.

55 lb 12 oz.

(b) Dimensions of Backpack EUIDE

Height 13 1/2" Width 11 " Length 18 7/8"

( c) PumEing unit. protrusions

Unit ~IA" is free" of protrusions which might cause damage or be damaged when reasonable care is used in handling. The threads on both the suction and discharge are protected by slip-on caps. The cylinder, spark plug and flywheel are covered by a protective hood. The unit is provided with a tubular-__ p-rotective U-bar which passes over the top of the engine and may be bolted to the base frame to prevent damage during transport.

Cd) Arrangements for carrying and back-packing

For back-packing OVer long distances a padde.d canvas backpack p'~mp harness is. provided. (Fig. 2) The harness is designed to hold the unit in a vertical position by securing the base frame with four fasteners and a shallow pocket. A 211 belt fastens around the carriers 1 waist and supports the bottom of the backpack. Two 2" shoulder straps are attached to the top of the backpack and fasten to the waist belt. At breast height a belt buckles around the shoulder straps to keep them in position. Using this harness the pump may be transported over considerable distarices without undue strain or discomfort to the carrier. (Photo No.2)

The tubular base frame which arches up at each end of the pump acts as a natural handle for positioning the unit or carrying it over short distances. Also the tubular U-bar, if attached, can be used for this purpose.

The standard four-gallon backpacking fuel tank is provided with both a handle and carrying straps.

(e) Adequacy of nameplate instructions

Starting and operating procedures as well as the proper fuel mixture are well described on an instruction plate located on the engine shroud. Labe~s

indicate the choke position, ignition switch position, pump suction inlet and fill cap.

A label on the fuel tank indicates the proper fuel mixture, (1/2 pint of oil to 1 Imp. gallon of gasoline) and tank capacity in both French and English. The air vent is also labelled.

(f) Conformity to plans, specifications and manuals

The unit conforms well to all literature supplied by the manufacturer. The literature includes: a service manual with ample illustrations, parts list, trouble chart as well as a detailed operating, maintenance and servicing instructions. Thr9ughout the tests no difficulties were encountered in the interpretation of the literature.

3

Photo No.1 Instrument paneZ

Photo No.2

Carrier transporting Gorman-Rupp Backpack pump, Backpack pump harness (insert)

4

Photo No.3 Fuel inlet and control side of Gorman-Rupp

Backpack pump.

Photo No. 4 Exhaust side ol Gorman-Rupp

Backpack pump.

5

Orientation Tests (Unit "A") Spec. No.5

(a) Horizontal Test

Unit "A" was operated at various discharge pressures and flow rates with the base in a horizontal position for a total accumulated time of 40 min. During the test the unit stopped five times due to air entertng the carburetor from the fuel tank fuel line. This fault will be described later in the report. (p. 14) Periods when t~e fu.el flow was constant, the lIDit operated quite satisfactorily with no' undue vibrations or tendencies to creep. No difficulty was encountered in priming the pump or maintaining the prime. Priming could be accomplished equally-well by filling the pump at the fill cap or by plunging the suction hose and footvalve up and down in the water. The engine required an average of four pulls 'on the rewind starter for each restart.

(b) Tilt Test

Unit "A" was run with the base tilted from ~he horizontal appro'ximately 20

0 fo'r eight 5-minute periods, each edge and corner of the base being in the

IIdown" position successively. No irregularities in performance were noted at any of the tilt positions. However, excess air in the fuel line ~aused engine stoppage once and on one occasion it was.-necessary to shut down in order to tighten'loose muffler bolts.

Shut-off Test (Unit nAn) Spec. No.6

Unit IIAII was run at zero feet suction lift and full thottle with a

\

o water temperature ,of 25 C. The rate of flow was glowly decr.~ased to zero by closing a ball valve located four feet from the pump outlet. A maximum' shut-off pressure ~.

of 245 psi was attained. At the completion of the five minute shut-off period the pressure had dropped to 220 psi. Upon shutdown, steam and boiling water escaped from beneath the fill cap.

Performance test at minimum suction lift (Unit itA") Spec. No. 7.1

The relationship between discharge pressure in pounds per square inch and discharge flow rate in gallons per mfnute were recorded in 10 psi intervals between free flow and the shut-off pressure as determined in the shut-off test .. Discharge pressures were regulated by a ball valve located near the pump outlet and discharge flow rates were determined by weighing the quantity of water pumped during a set time interval.

The maximum flow rate of 43 gpm was attained between 0-40 psi where the flow rate" remained reasonably constant. As the discharge pressure was increased beyond 60 psi, the' discharge flow rate decreased in an approximate linear relationship until shut-off pressure of 245 psi- was reached. The results are plotted in fig. No. 1.

Fuel consumption was determined for each point .in the performance test by measuring f~r a predetermined time the fuel consumed in a 50 mI. burette. The burette was joined directly to the fuel tank fuel line with a 3-way valve, to enable fuel to be drawn f,rom either fuel tank or burette. (Photo No.5)

The results obtained showed a direct increase in fuel consumption as the pump discharge pressure increased. Fuel consumption rate ranged from a minimum

6

of 0.62 Imperial gallons per hour at,23 psi to a maximum of 0.96 Imperial gallons per hour at 230 psi. The results are given in Fig. No.1.

Suction lift perfonnance test (Unit HA") Spec. No. 7.2

This test was performed to determine the relation between discharge flow rate in gallons per minute and suction lift between minimum and 25 ft. The res,ults were obtained by using equivalent vacuum gauge readings in place of actual suction lifts. Equivalent suction lifts were attained by constricting the flow of water at the suction end with a 1 '1/2" ball valve and regulating the pump discharge pressure with a second 1 1/2" ball valve attached near the pump

',outlet. The equivalent suction lifts were varied from minimum to 20 ft. in 5 ft. increments for discharge pressures of 75, 100, 150 and 200 psi.

The results showed 'that a significant reduction in discharge flow rate occurred when the suction lift was higher than 10 ft. for discharge pressures of 75 and 100 psi; higher than 15 ft. for 150 psi and 20 ft. for 200 psi. The results are given in Fig. No.2.

During the summer of 1969 a series of tests using actual suction lifts were performed on a new Gorman-Rupp Backpack pump-' of the same model used in the specification tests. Comparison ell'rYes are plotted showing the relation in discharge flow rate between equivalent suction lifts and actual suction lifts for discharge pressures of 75, 150 and 200 psi. See Appendix 1.

Series (tandem) ope ration Spe c. No. 8 .'

Pump units "A" and "B" were set up a distance. of 3 ft. apart, joined by a short length of latex-lined hose. Pump Unit A was operated for one hour at.a discharge (ressure of 416 psi or 17,0 per cent of the pump 1 s shut-off pressure while being supplied with inlet water from Unit "B" at a pressure of 204 psi or approximately 85 per cent of Unit "A'''s shut-off pressure. (Photo No.6)

During initial adjustment, ~with Unit "A" discharging at a pressure of 350 .psi, one side of the rubber Fill Cap gasket slipped from beneath the Fill Cap releasing a spray of water. The gasket was repositioned and it stayed in place for the remainder of the test. Both pumps operated quite satisfactorily with no unusual signs of distr·ess. Unit "A" produced a discharge flow rate of 10.0 Imperial gallons per minute at the· discharge pressure of 416 psi.

Hydrostatic test (Unit "All) Spec. No. 10

This test was designed to subject the pump to a hydrostatic pressure of 250 per cent of the shut-off pressure for five minutes to measure any pump leakage. A Golden Arrow pump, driven by an ~lectric motor and coupled to a Silver Line Static Pressure Accumulator was used in an attempt to attain a hydrostatic pressure in pump Unit "A" of 617 psi (250% of shut-off pressure). During the test, the hydrostatic pressure was increased in increments of 100 psi and held for an interval of one minute while checking for leakage. On six consecutive attempts, one edge of the Fill Cap gasket slipped from beneath the Fill Cap causing a loss of water and pressure. The gasket slipped when the. following hydrostatic pressures were approached: 500, 275, 325, 600, 625 (pressure surge) and 450 psi. On one occasion a hydrostatic pressure of 500 psi -was maintained for 4 minutes without any detectable sign of leakage. Throughout the .test there was no detectable evidence of leakage other than around the Fill Cap.

7

Photo No.5

Apparatus for measuring fuel consumption.

Photo No.6

Series (tandem) operation set-up.

8

Muddy water test (Unit "A") Spec. No. 12

200 gallons of water were measured into a galvanized metal tank. 20 pounds of Standard Sand of the following composition were added:

20% less than 30 mesh ·30% less.than 40 mesh

30% less than 60 mesh 20% less than 100 mesh.

Unit "Au was operated at minimum suction lift and full throttle with both the suction hose (foot valve strainer removed) and the discharge hose immersed in the muddy water tank. The pump discharge Was used to keep the muddy water constantly agitated. Discharge pressure was regulated by a 1 1/2 inch gate valve located at the pump outlet.

The pump was run for 2 hrs. 46 min. at a discharge pressure of 163 psi (two-thirds of the shut-off pressure) when the pump seal failed. The test was discontinued immediately as the loss of water from around the pump seal and engine shaft was too great. The seal was examined and considerable scoring on the face of the carbon 'sealing washer was noted. (Photo No.7)

A replacement seal was supplied by' the manufacturer and installed in the pump. Using the same procedure as outlined above, the muddy water was circulated through the pump for a period of 8 hours, 4 hrs. at a discharge pressure of 163 psi and 4 hrs. at 49 psi (one-fifth of the shut-off pressure). No leakage was observed during the rerun.

The muddy water temperature was kept below 30De for the first test

whereas during the rerun the muddy water was allowed to heat up to a maximum of 34°C due to the lack of time available. The higher temperature did not seem to have any adverse effect upon the Unit's performance.

Performance at 5 ft. suction lift before and after muddy water test (Unit "A") Spec. No. 7.3

Unit "All was operated with an actual 5 ft. suction lift to determine the relation between discharge pressure in pounds per square inch and dis.charge flow rate in gallons 'per minute, both before and after the ruddy wa,ter test.

The results showed that there was an increase in discharge flow rate after the muddy water test for discharge pressures up to 81 psi and a decrease in discharge flow rate for pressures above tbat point. The results are plotted in Fig. No.3. Disassembly exarrlnation (Unit "A")

Prior to running the muddy water test and following a total accumulated operating time of 17 hr. 50 min. the pump was disassembled and examined for wear and damage. The component parts of the pump showed neither sign of wear or damage.

The disassembly time was approximately fifteen minutes as some difficulty was encountered when unscrewing the Unit's single impeller from the engine shaft. Reassembly was completed within a time of five minutes. No specializ.ed tools were required for this operation.

9

Photo No. 7

Photo No. 8

Carbon sealing washers. Left washer shows scoring resulting from the first muddy

water test. Right washer used in Unit "B" --200 hours, clean water.

Impellers. Right impeller show wear resulting from muddy water tests. Left

impeller used in Unit "B" -- 200 hours, clean water. No sign of wear.

10

The pump component parts were again examined following the pump seal failure at an elapsed time of 2 hr. 46 min. and at the completion of the test following a total elapsed time of 10 hr. 46 min. The observations are as follows:

Muddy water test No. 1 (2 hr. 46 min.)

Seal:

There were distinct grooves circling the face of the carbon sealing washer. These were caused by the abrasive action of sand particles getting between the washer and the stationary seal element on the impeller hub. The stationary seal element showed little sign of wear. (Photo No. 7)

Intermediate bracket:

The intermediate bracket is that "part which seals the back of the volute or casing. There was noticable wear around the outer face of this bracket. The outer edge was slightly rounded and the face was polished a distance of approximately 3/8 in. in from the outer circumference.

Impeller:

The impeller, which had been tinted a green colour by the manufacturer showed some loss of this tint around radial vanes and on the impeller hub.

Volute:

The fine machining circles within the volute had become partially obscured by the abrasive action of the sand particles. A shallow groove had formed where the outside circumference of the intermediate bracket touches the outer rim of the volute.

Muddy water test No.2 (8 hr.)

Seal:

The face of the carbon sealing washer was dulled on the outside half while the inner half retained its original lustre. No distinct scoring ".,as noted. The stationary seal element showed' no visible ~ign of additional wear.

Intermediate bracket:

The outer edge of the bracket had been bevelled and the face polished.

Impeller:

The muddy water caused considerable wear to the' impeller. A hole,hqd been sco~red through, the wall of every sixth or'main radial

'vane with, the intermediate vanes being worn to a lesser extent. Wear

11

Photo No.9

VA lute, unit "A ", after the muddy water tests. Note grooves "A" and "B" worn by the muddy water.

Photo No. 10 Endurance test set-up.

12

to the conical hub was substantial. (Photo No.8)

Volute:

Extensive wear had taken place within the volute. The discharge channel had been enlarged and two pronounced·groves had formed on the rim, one on each side of the discharge "channel. (Photo No.9)

Uni t "All, adj us tmen ts, repai rs and replacements

Backpack pump Unit "A" was operated for a total accumulated time of 31 hr. 23 min. in order ,to complete the assigned tests. Throughout this time the unit ran with a minimum of difficulty, It started consistently with less than five pulls on the rewind starter when the engine was' cold and one or two pulls when the engine was warm. Prior to each test the spark plug gap was checked and routine adjustments were ,made to the carburetor. The Unit requires no lubrication other than the fuel mixture for the i-cycle engirie. Repairs, adj us t~ents and replacements included the following:

the muffler bolts required retightening three times. (accumulated time -- 1 hr. 9 min., 2 hr. 23 min., and 28 hr. 55 min.) retorqued the cylinder head bolts after 5 hours as recommended in the service manual. replaced one rivet holding the pressure switch bracket (accumulated time -- 8 hr. 6 min.) re-tightened.air filter cap screws (accumulated time -- 8 hr. 6 min.) replaced ,carbon sealing washer (accumulated time -- 20 hr. 36 min.) repaired rewind starter (accumulated time -- 20 hr. 36 min.)

200 hour endurance tes t (Un'i t liB ") Spe c. No. 11 (Photo No. 10)

Unit" liB" was run at minimum suction lift at a discharge pressure of 147 psi and 184 psi or 60 and 70 per cent of shut-off pressure respectively. The pressure was alternated every 4 to 8 hours until 100 hours at each pressure was accumulated. Discharge pressure was regulated by a 1 1/2" ball valve located near the pump outlet. As a general practice, the main adjustment screw on the carburetor was adjusted following each warm up period and after a pressure change to ensure that the unit was operating at peak performance.

To complete the 200 hour endurance test, the unit consumed a total of 183.9 gallons of fuel at an average rate of consumption of 0.92 gallons per hour. This quanti tyincluded 10.8 gallons of oil combined wi th 173.1 gallons of gasoline.

Major endurance test problems:

The major difficulties encountered while performing the endurance test are as follows:

1. Carburetant leak aroun"d the magneto seal. 2. Air entering the fueline. 3. Rewind starter failure.

A carburetant leak at the magneto seal developed at the onset of the endurance test. The fuel mixture was escaping between the crankshaft and the magneto seal from the crankcas~. This resulted in the saturation with carburetant

13

of the breaker points and the other component parts of the magneto. The problem was alleviated to some extent by clipping a piece from the bottom of the breaker box cover gasket. This allowed increased drainage from the area' enclosed by the breaker box cover gasket and lessened the rate of accumulation of carburetant on the breaker points. After 44 hours of endurance operating time a new seal was installed. However, the replacement seal failed to stop the leak although there were intervals near the conclusion of the test where the leak stopped temporarily.

On many occasions the unit would only., start after the breaker points had been throughly dried. ,This necessitated the removal of both fan housing and flywheel. Once running, the unit would operate quite satisfactorily with only brief periods when the engine would misfire due to the saturation of the breaker points by the fuel/oil mixture.

The abrasive action of the carburetant which appeared to be contaminated with carbon caused accelerated wear to the.high point of the cam and the cam follower. This made it necessary to adjust the breaker points an excessive number of times.

The chief cause of premature engine stoppage was attributed to air entering the carburetor from the fuel line. It was noted that at all times a fine

, stream of bubbles flowed along the transparent plastic fuel line between the quick-connect coupling and the carburetor inlet. These bubbles did not appear to have any adverse effect upon the engine t s performance. However, on a number of occasions, the size of the bubbles would increase conSiderably, creating a substantial gap in the fuel entering the carburetor. If the quantity of air entering the carburetor was not sufficient to completely stall the engine, normal fuel flow would generally resume in a matter of seconds.

It was later discovered that the section of plastic fuel line within the fuel tank itself was loosely clamped to a short 3/8 in. nipple situated on the underside of the fuel tank top. The single wire clamp, securing the plastic tubing to the fuel tank outlet applied little direct pressure, as the fuel line could be easily slipped from the nipple. It was observed that the quantity of air entering the carburetor could be regulated by moving the plastic tubing at this point. This fault was present in both fuel tanks supplied for testing.

Engine starting Was also hampered by this fuel line problem. A 7 ft. 9 in. neoprene fuel line with a quick-connect coupling connects the fuel tank to the engine. It is provided_with a squeeze-type hand priming bulb used to pump fuel· to within 2 or 3 inches of the carburetor inlet. However, quite frequently, while cranking with the carburetor in the choke position, the engine fuel pump was unable to create sufficient vacuum to pull the fuel into the carburetor. When this occured, a small quantity of fuel poured directly into the cylinder through the spark plug opening was usually sufficient to start the unit. Once the engine Was running the fuel would flow normally. This problem did not occur while sta,rting the Unit when the engine was warm.

The unit is supplied with a Fairbanks - Morse reversible left or right hand operation automatic rewind starter. Periodically the starter would fail when cranking the engine. Generally, this would occur only after the rewind starter had been pulled many number of times.

It was found that the rotor was binding within the cover preventing the pull cord from rewinding. This necessitated the removal of the rewind st.arter from the fan housing. The tension· on the rotor was then released by removing the

14

friction shoe assembly and lifting the rotor up slightly on its shaft.

Performance at 5 ft. suction lift before and after the 200 hour endurance test (Unit "B") Spec. No. 7.3

Unit B was operated with a 5 ft. suction lift to determine the relation between discharge pressure in pounds per square inch and discharge flow rate in gallons per minute, both before and after the-200 hour endurance test.

Near the conclusion of the 200 hour endurance test the Unit's engine was showing signs of deterioration and was in need of overhaul. During the final performance test it was often difficult to maintain a constant discharge pressure as the engine was running quite roughly, causing pressure flucuations of up to 20 psi. However, the flowrate for each discharge pressure was established when the Unit Was performing in a reasonably sta~le manner.

The results showed that there wa's a drop in shut-off pressure from 245 psi to 205 psi between the beginning and the end of the endurance test.· There was also a corresponding drop in discharge flow rate at e-ach discharge pressure calibrated. The results are given in Fig. No.4.

Disassembly Examination (Unit IIB")

Pump Unit B was disassembled following a total accumulated operating time of 215 hr. 32 min. Upon examination, the pump's component parts showed no visible sign of wear or damage. The time required to disassemble the pump was approximat~ly 5 minut.es.

15

Date 1968

Unit "B" operation record

Total Accumulated Ease Stoppage and running running time per time

of reason start 1/

Adjustments, repairs and replacements ~

1------ __ ~'Iy~---- _____ ____ _ -_._------ -- -------------------+---------------j

hr. min.

Jul.19

0: 42

22

5: 13

24 1: 39

Jul. 24

2: 31 .--------- - ---

I 25

26 7 : 27

- - - - -- - - - - - -

30

5: 15

hr. min.

OPERATION RECORD BEFORE ENDURANCE TEST

0: 42

4: 15 4: 37

1

1 1

5: 55 2

daily shut-off

ran out of fuel temporary shut­off daily shut-off

--- --------~----

7: 34

1: 44

2: 31

8: 59

16 : 26

- - - -

17 : 08

21: 41

1 daily shut-off

ENDURANCE TEST OPERATION RECORD

- -

1 unknown,

1 - - -,- - - -

- -

3

3 daily shut-off

3 main adjustment screw adjustment

1 daily shut-off

Adjusted breaker points and spark plug gap. Performed minor adjust­ments on both main ' and idle adjustment screws after the Unit was started.

replaced one pressure switch bracket rivet.

--------------repaired rewi~d starter

replaced spark plug

retorqued cylinder head bolts and tightened air filter cap screws.

,____ _ ____ __ . _____ . _________________ . _______________ ----'--..L ____ ......J _______ ---4

16

31 r---- -... -I -- .- - - --.. .- ....... ------T ... - ._-21: 41 4

I

, . 2: 42 I 24: 23 1

1- - - -2 - - .- - ,- - - - - - - - - - - - - - - - - -

I

6: 16

3

4: 57 ------

4

6: 03 ------

5

0: 45

6

1: 35

7

9

0: 34

27: 27

28: 08

30: 39

31: 55

35: 36

35: 36

37: 44 41: 39

42: 24

42: 24

43: 59

43: 59

44: 33

1

3

1

2

3

4

1 1

1

4

3

1

17

not o"perated

daily shut-off

dried and adjusted breaker points.

-. - - - - - - - -1- ~ - - - - - - - - - - - - -

temporary shut­off

temporary shut­off daily shut­off

air in fuel line

temporary shut­off

did not start

unknown See note 'if

·1 dried breaker points, t retorqued cylinder head bolts.

rep laced b reake r points.

r~paired rewind starter, retorqued cylinder head bolts.

dried breaker points, retorqued cylinder head bolts.

repaired rewind starter, dried breaker points.

injected fuel into ,I

cylinder.

- - - - - - r - - - - - - - - '- - --wet breaker points

did not start

daily shut-off

not operated

daily shut-off

dried breaker points

adjusted breaker points tightened crankcase cover, injected fuel in to cylinder.

dried breaker points.

replaced magneto seal, breaker points and cam

10 i injected fuel into I cylinder.

47: 34 1 temporary shut-off

dried breaker points, replaced spark plug.

5: 06 49 : 39 1 daily shut-off - - - - - --- ---- ----------- --- -- ---- ------ --------- -- - ----

11 injected fuel into cylinder.

52: 13 1 temporary shut-off

5: 06 54: 45 1 daily shut-off -- - -- ------- ---------- - - -- ---- - - - - --- - -- -----------

12 repaired rewind starter, dried breaker points.

60: 54 3 temporary shut-off

dried breaker points, replaced spark plug, cleaned carburetor strainer, injected fuel into cylinder.

, 61: 10 1 temporary shut-ofLto replace tachometer tape

62: 36 1 air in fuel line

10: 53 65: 38 1 daily shut-off - - - - _. -------- --- ----- --\-::-, - - - - ~ - -- ------- - - - -- --- -------

13- dried breaker points, injected fuel into cylinder.

66: 06 3 unknown 70 : 56 1 air in fuel

line. 77: 44 1 air in fuel

line. 12: 50 78: 28 1 daily shut-

off - - - -- -------- ------------ - ---- ---------- ---------------

14 dried and adjusted breaker points, injected fuel into cylinder.

2: 27 80: 55 1 daily shut-off

----- -------- ------------- - - --- - _._- -------- ----------------15 injected fuel into

3/ cylinder.

1: 16 82: 11 1 See note - ---- --- - --_. ------- - - - - - -- ---------- - ------_._---- -~-

16 83: 43 unknown 85 : 18 1 temporary shut-

off L--_ -

18

13: 51

86: 21 88: 25

96: 02

1 1

1

loss of prime temporary shut­off daily shut-off

dried breaker points, injected fuel into cylinder,

- - - -_. - - - - - - - - - - - - .- - - - - - - ~ - - - - - - - - - - - - -- - - - - - - -- - - .- - - - - - - - .- -17

97: 21

98: 52 100: 00 101: 13

103: 44 10: 09 106: 11

---ii-I--------,----------- --

6: 48

. 19

13: 21

106: 48

Ill: 21 112: 59

116: 47 120: 41

124: 25 126: 20

1

1 1 1

air in fuel linE

air in fuel linE air in fuel line temporary shut-off

1 unknown 1 daily shut-off

replaced flywheel hex nut, cup and screen. The cup and screen was damaged after the flywheel hex nut loosened.

injected fuel into cylinder

-----------------------------,---

1

1 1

1 1

air in fuel line. unknown daily shut-off

unknown air in fuel lin

1 unknown 1 daily shut-off

dried breaker points, replaced spark plug,

dried and adjusted breaker points, injected fuel into cYlinder'1

-------------------------_._--------------- ------- ----- T--20

14: 33

21

7: 31

22

135: 32

140: 53

1 main adjustment screw adjustmen

1 daily shut-off -------------------------------------------

146: 47 147: 01 148: 24

148: 31

1 1 1

3

19

unknown unknown daily shut-off

temporary shut­off to tighten

dried and adjusted breaker points, regap­ped spark plug,

dried and adjusted breaker points, injected fuel into cylinder,

U-\

.

151: 33 ,

155 : 24

9: 08 157: 32 __ .1 ___ ----- _. --------- -

23 1159

: 17

I

1160 : 59 ,

167: 20 11:05 168: 37

-- --- ------- --- -- ------24

·170 : 13

9: 42 178: 19

1

1

1

----1

1

3 1

- ---

3

1

loose muffler bolts. teptporary shut-off temporary shut-off daily shut-QU __ .. ____ . air in fuel line

, temporary shut­off

unknown daily shut-off

broken coil primary lead.

daily shut-off

adjusted fuel line.

replaced spark plug.

replaced b~eaker points, condenser and spark plug.

replaced coil primary lead.

25 dried and adjusted breaker points.

10: 36 1188: 55 1

- - -26· -- ---- t------ ----- -----I I

190: 20 1

11: 41 200: 36 1

daily shut-off

temporary shut­off shut-off -- end of endurance test,

OPERATION RECORD AFTER ENDURANCE TEST

2: 48 2: 48 1 daily shut-off

28 ,

I 2: 07 I 4: 55 1 daily shut-off

20

replaced vibration mounts,· reinstalled retainer ring and brake retainer washer (slipped off of the rewind starter) J

regapped spark plug.

dried breaker points, replaced rewind start­er friction shoe assembly, regapped spark plug.

tightened muffler bolts.

--------~-------,-----~-------~--------,---------, , Oct. 1 I 4: 55

--~ - ~ 'I ~ -~ --- --, -- ~~ -- ~ -.. ~ ~ 7 2: 27 1.7: 22 1

not operated

shut-off -- end of tests.

Total accumulated operating time - 215 hr. 32 imino ~ __ L-______ _

NQte ~ Ease of start:

(1) - easy, 1-10 pulls (2) moderate, 11~20 pulls (3) difficult, 2l+ pulls (4) would not start without repair.

replaced ground lead, coil wedge spring, breaker points, condenser and spark plug.

In mos t cases the uni t 'would not start prio'r to drying the breaker points or injecting fuel into the cylinder (See page -l3 and page 14). In these instances, the ease of start given applies after these procedures were followed.

Note Y Note '}j

All adjustments, repairs and replacements listed were made just prior to engine, start. No stoppage is listed as the unit was operated past midnight.

.

1.0 ~

0 " W 0 0.9

~ I ::>-41 (J) z 0 U .J w J IL

Q.

.; til

(!)

ri. E

Q) -" c

~

Q)

Q.

VI

0.8

0.7

0.6

50

40

til 30 (!)

a. E

UJ (!) 0:: « I

20

U 10 (J)

o

o 20 40

Figure No.1

. \ •

FUEL CONSUMPTION

VS

DISCHARGE PRESSURE

DISCHARGE FLOW RATE VS

DISCHARGE PRESSURE

60 80 100 120 140 160 180

DISCHARGE PRESSURE - Lbs. Per Sq. Inch

GORMAN _ RUPP BACKPACK PUMP

UNIT"A" PERFORMANCE AT MINIMUM SUCTION LIFT. SPEC. 7.1

200 220 260

40 _

30

'" ~ :> c

::E .. ~

'" a. I/)

ttl (!)

c. 20 E

LU (!)

.0:: <l: I U (J)

0

10

o 5

Figure No.2

10

DISCHARGE PRESSURE

® 75 PSI

100 PSI

.. 150 PSI

.. 200 PSI

15 20

SUCTION LIFT - Ft. of Water

GORMAN - RUPP BACKPACK PUMP

UNIT "A" PERFORMANCE AT VARIED SUCTION LIFT. SPEC. 7.2

25

~

" a. I/J

50

40

" 30 (!)

0-E

w (!) a: ~ I U Ul o

20

10

o

x

20

Figure No.3

" 40 60 80 100 120 140 160 180 200 220 240 260 ,

D1SCHARGE PRESSURE - Lbs. Per Sq. Inch

GORMAN _ RUPP BACKPACK PUMP

UNIT"A"PERFORMANCE AT 5FT. SUCTION LIFT BEFOREANDAFTER MUDDY WATER TEST. SPEC. 7.3

50

" ~ :J C

~ 40

~

" n. Ul

'" 30 (.'J

"-E

w 20 (.'J c:: « I U (f)

10

Cl

o 20 40 60

Figure No.4

80 100 120 140 160 180

DISCHARGE PRESSURE - Lbs. Per Sq. Inch

GORMAN - RUPP BACKPACK PUMP

200 220

UNIT ·'B" PERFORMANCE AT 5 FT. SUCTION LIFT BEFORE AND AFTER ENDURANCE TEST. SPEC. 7.2

240 260

" -" c

::i: ~

" a. U) .. (!)

c. E

I w I-<l: a:: ~ 0 ...J U.

40t--___ -==""Ir-'_~_:_:::_:_= __ :::::=_----__ I --

Appendix 1

DISCHARGE PRESSURE 75 PSI - ----..... ACTUAL SUCTION LIFT, UNIT "C", 1969 _

30

20

.....

------

.... .... .... ,

" " " , " ,

\ \

\

\ It

~---x------__ _ --,...----------~-DISCHARGE PRESSURE 1:>0 PSI'

-~--------~---------- -)$- -- ------

"

EQUIVALENT SUCTION LIFT, UNIT "A", 1968,...._-«

" , \

\ \

\ \ \ ~

f~~~~~~~~~~~~~;s~------------=-~-~::~~~~~~~~~~~~~~ ____ __ DISCHARGE PRESSURE 200 PSI ""-_ 10 -- __ _ ---

o 5 10 15 20 25 30

SUCTION LIFT -.Ft. of Water

GORMAN - RUPP BACKPACK PUMP

COMPARISON BETWEEN EQUIVALENT AND ACTUAL SUCTION LIFT. SPEC. 7.2