GMC 1976 ZEO 6083 Maintenance Manual page 683

24C- 6
ONAN MOTOR GENERATOR
FUEL SYSTEM TROUBLE DIAGNOSIS
Problem Possible Cause Correction
Fuel leaks from carbu- 1 . Float level set too 1 . With fuel bowl removed and
retor when fuel shut-off high . carburetor inverted, set float
is open . parallel to bowl flange . (3/32"
clearance)
2. Dirt under inlet valve. 2. Remove inlet valve, clean seat
by rinsing in clean fuel and blow
off with compressed air.
3 . Bowl vent plugged. 3. Remove bowl and blow clean
with compressed air.
4. Collapsed float caused 4. Replace float.
by blowing assembled car-
buretor with compressed
air .
5 . Carburetor gummed from 5. Remove fuel bowl and clean.
storage. Float stuck to
screen .
Engine smokes and runs 1 . Dirty air filter . 1 . Clean or replace .
rich .
2. Improper adjustment . 2 . Set idle & power needles at 1
turn open . After engine starts and
runs, set for optimum performance.
3. Nozzle boss gasket 3 . Remove fuel bowl and replace
leaks. Engine runs with gasket . Tighten bowl retainer
power needle seated . securely .
4. Air bleeds in carbu- 4. Remove fuel bowl, idle & power
retor plugged.
needles. Clean thoroughly with
compressed air .
Engine runs lean . 1 . Improper adjustment .
1 . Set idle & power needles at 1
turn open . After engine starts and
runs set for optimum performance.
2. Idle holes plugged.
2. Remove fuel bowl, idle & power
Dirt in fuel delivery
needles. Clean thoroughly with com-
channels . Pressed air.
3. Float level set too
3 . With fuel bowl removed and
low. Low level in fuel
carburetor inverted, set float
bowl .
parallel to bowl flange (3/32"
clearance) .
4. Fuel filter in elec- 4. Remove filter and replace.
tric fuel um dirty.
5. Fuel filter screen in 5 . Remove fuel bowl . Invert bowl
fuel bowl plugged. and tap on flat surface. Clean
thoroughly and replace.