Fuel System.21 - Onan CCK Service Manual

Fuel System
Satisfactory engine performance is largely depend¬
ent upon correct fuel system adjustments. However,
adjustments cannot fully compensate for low engine
power due to wear, etc. If trouble develops, follow an
orderly procedure to determine the cause before
making any adjustment.
The carburetor idle and main mixture were set for
maximum efficiency at the factory and should nor¬
mally not be disturbed. If adjustments seem neces¬
sary, first be sure the ignition system is working
properly and governor sensitivity is properly adjusted.
Adjusting the carburetor is a means of obtaining the
correct fuel-to-air mixture for smooth, efficient
operation.
GASOLINE AND GAS-GASOLINE
CARBURETORS
CHOKELEVER
The carburetor has idle fuel and main fuel adjustment
screws (Figure 14). if engine runs unevenly at half or
full load due to faulty carburetion, the main fuel
adjustment needs adjusting.
If the carburetor is totally out of adjustment the mix¬
ture settings given below should be used as a preli¬
minary adjustment. Turn the mixture screws in until
lightly seated, then turn out the specified number of
turns.
Forcing the mixture adjustment
screw tight will damage the needle
and seat Turn in only untlf light tension can be left.
TABLE 1. CARBURETOR ADJUSTMENTS
ENGINE IDLE MAIN
MODEL
ADJUSTMENT ADJUSTMENT
CCK/CCKA
1 tO 1-1/4 1-1/4 to 1-1/2
CCKB
1-1/2 2 to 3
WARNING I T-handled main adjustment screws
■i ■ are locked in position with a packing
nut. This nut must be loosened before adjustments
are made and retightened afterward. Failure to tighten
the packing nut may resuit In leaking fuel, creating a
serious fire hazard.
CCK/CCKA DOWN DRAFT TYPE
IDLE FUEL
ADJUSTMENT
21