Bolens 248-645A - Manual (Page 14)

I
CLEANING ENGINE
Dirt, leaves and other debris must not be left to
accumulate around the cooling fins (figure 29) or
the engine.
The blower housing is held in place with three
screws. One on the top of the engine and two on
the bottom. See figure 29.
Clean Out
Chaff And
Dirt
Cooling
Fins
FIGURE 29
SPARK PLUG
The spark plug gap should be cleaned and reset to
a 0.030-inch clearance every 25 hours of engine
operation. See figure 30. Spark plug replacement is
recommended at the start of each tiller season;
check engine parts list for correct plug type.
FIGURE 30
GASOLINE FILTER AND SHUT-OFF VALVE
Refer to figure 31.
1. Close the shut-off valve.
2. Loosen the thumb screw below the bowl.
3. Remove and clean the screen.
4. Open the shut-off valve to see if gasoline flows
freely from the gasoline tank.
5. Clean the bowl and screen. Use alcohol or
acetone to clean the parts if you find a gummy,
varnish-like substance in the bowl.
6. Reassemble.
7. Open the shut-off valve.
Thumb Scr«w
FIGURE 31
CARBURETOR ADJUSTMENT See figure 31
Minor carburetor adjustment may be required to
compensate for differences in fuel, temperature,
altitude and load. To adjust:
1. Turn needle valve clockwise until it just closes.
A
CAUTION
14
Valve may be damaged by turning
too far.
2. Open needle valve 1-1/8 turns counterclock­
wise.
3. Close the idler valve in the same manner and
open 1-1/8 turns.
4. Start the engine.
5. Turn the needle valve in until the engine misses.
6. Then turn it out past smooth operating point
until the engine runs unevenly.
7. Turn the needle valve mid-point between the
two settings so the engine runs smoothly.
8. Set the throttle in the idle (slow) position and
set the idle speed adjusting screw until a fas“
idle is obtained.
9. With the throttle still in the idle position, turn
the idle valve in and out until the engine idles
smoothly.