PRESSURE TEST - TM-10-3930-607-150083

FUEL

the adapter, insert the bolts with lockwashers in the

holes provided for them.

4. Start the bolts and turn them in finger tight. This

will prevent damage to the threads. Then tighten bolts

with a wrench.

5. Check the fuel lines for condition, cleanliness

and alignment with the pump outlet. Start the fitting

nuts and turn on finger tight. Using two wrenches, one

on the nut and one on the fuel pump fitting, tighten

enough to prevent vacuum and fuel leaks.

G. PRESSURE TEST

NOTE

The pressure test is made to check

for excessively high pressures

developed by the pump which may

cause rich fuel mixtures, and in a few

Figure 8.

cases, flooding of the carburetor. A

rich mixture is one of the causes of

CAUTION

excessive fuel consumption and

Disconnecting the line between the

poor performance.

carburetor and the pump removes

the normal pressure on the fuel

1. Disconnect the gasoline line at the carburetor,

pump diaphragm causing it to flex

and insert a "T" fitting between the carburetor and the

abruptly.

This may cause loose

fuel line. (Fig. 8)

particles of dirt to enter the

2. Start the engine and run it at low idle speed.

carburetor fuel line.

Therefore,

3. Read on the pressure scale the pounds pressure

before connecting the line to the

developed by the fuel pump and compare with the

carburetor, it is recommended that

specifications.

the fuel line and pump be flushed.

To do so, operate the starter until 1/4

H. CAPACITY TEST

to 1/2 pint of gasoline has been

flushed out into a container.

NOTE

The capacity test determines the

2. Start the engine, and measure the time required

ability of the pump to produce a

to pump one pint of fuel into the container, at 1800

sufficient amount of fuel within a

RPM. This should take one to 1-1/2 minutes.

specified time. It is important that

3. If the capacity of the fuel pump is low, it may be

both a pressure and a capacity test

due to leakage of air into the system. Check the vapor

be made to determine the condition

dome for looseness and also the gasoline line to the fuel

of the fuel pump.

tank and the inlet fitting on the pump for air leaks.

Restrictions in the fuel line will also reduce pump

capacity.

1. Disconnect the rubber hose at the tester and

insert it in a suitable container. The container must be

marked to show a one-pint level.

B-46