Engine
Maintenance
4Clean Cooling System Grass or chaff may clog cooling sys- tem after prolonged service. Continued operation with a
clogged cooling system causes severe overheating and possi- ble engine damage. Remove blower housing and clean
regularly.
~Ir:===;
({J
9,
~ 
,
'==""'/
-~4d~[=.ifL.
5Spark Plug Clean and reset gap at .030" every 100 hours of
operation.
Caution: Blast cleaning of spark plugs in machines that use abrasive grit is not recom- mended. Spark plugs should be cleaned by scraping or wire brushing and washing with a commercial solvent or gaso-
line.
Refer to chart on page 19 for replacement spark plugs.
Refer to chart on page 19 for replacement spark plugs.
Adjustments
6Remove Carbon Deposits
Clean combustion chamber. top of piston and around both valves every
7 Carburetor Adjustment. Minor
carburetor adjustment may be required to compensate for differences in fuel, temperature, altitude and load.
To adjust the carburetor. turn the needle valve clockwise until it just closes.
Caution: Valve may be damaged by turning it in too far.
Now open the needle valve 1 Ys turns counter clockwise. Close the idle valve in the same manner and open 1 Ys turns. This initial adjustment will permit the engine to be started and warmed up prior to final adjustment.
Final Adjustment: Turn the needle valve in until the engine misses
(lean mixture) then turn it out past
smooth operating point until the engine runs unevenly (rich
mixture); now turn the needle valve
The use of unleaded gasoline is recommended because of less
to the