Onan MJA Series Service Manual page 31

29
FUEL PUMP AND
FILTER
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FUEL SYSTEM
If fuel is stored for any great length of time, it can oxidize and form
gums - the fuel becomes stale. ONAN recommends changing fuel
stored as often as every season to insure fresh fuel, especially where
there is a great change in weather between seasons.
3.2.2 MAINTENANCE
On gasoline fuel systems, periodic maintenance should consist of clean,.
ing the fuel strainer, cleaning or replacing the air silencer, Sect 3.2.6,
carburetor adjustment, and complete carburetor cleaning. For service
periOds, see the periodic service chart.
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To clean the fuel strainer, re ­
move the fuel sediment bowl
and the screen (Fig 3.2. B)
and thoroughly wash the
screen. At the same time,
remove the carburetor float
bowl and clean it. Reassemble
and check for leaks.
3.2. 3 FUEL PUMP (Gasoline
Fuel System)
The fuel pump is located on the
left side of the engine near the
rear.
If
fuel doesn't reach the
carburetor, make the following
checks - ­
Check the fuel tank and see
that the shut-off valve is
open.
Remove the fuel line from the pump outlet and crank the engine over
several times. Fuel should spurt out of the pump. If not, remove
the pump for repair "r replacement.
3.2.3.1 Testing. -
If
tt".
fuel pump delivers fuel, test
it
with a pressure
gauge or manometer. Perform these tests before removing the pump
from the engine. Disconnect the pump outlet line and install the pressure
gauge, Fig
3~2.C.
Test the valves and diaphragm by operating the priming lever a few
times and watching the pressure.
It
shOuldn't drop off rapidly after
priming has stopped. .
Next, run the engine at governed speed On the fuel.remaining in the car ­
buretor and measure the fuel pump pressure developed. Pressure
FIG 3.2.B - FUEL STRAINER