Poor Idle Or Low Speed Performance - Hisun HS700UTV-4 Maintenance Handbook

4. Check for retarded ignition timing. A decrease in power results when the plugs fire later than
normal
5. Check for one or more of the following problems
a. Low engine compression
b. Worn spark plug
c. Fouled spark plug
d. Incorrect spark plug heat range
e. Weak ignition coil
f. Incorrect ignition timing
g. Plugged throttle passages
h. Incorrect oil level (too high or too low)
i. Contaminated oil
j. Worn or damaged valve train assembly
k. Engine overheating
6. If the engine knocks when it is accelerated or when running at high speed. Check for one or more
of the following possible malfunctions:
a. Incorrect type of fuel
b. Lean fuel mixture
c. Advanced ignition timing
d. Excessive carbon buildup in combustion chamber
e. Worn pistons and/or cylinder bores

Poor Idle or Low Speed Performance

1. Check for an incorrect pilot screw adjustment
2. Check for damaged or loose intake pipe and air filter housing hose clamps. These conditions will
cause an air leak
3. Perform the spark test in this chapter. Note the following:
a. If the spark is good. Go to Step 4
b. If the spark is weak. Perform the Peak Voltage Testing
4. Check the ignition timing. If ignition timing is correct. Perform Step 5. If the timing is incorrect.
Perform the Peak Voltage Testing
5. Check the fuel system as described in this chapter
GENERAL INFORMATION
A clogged exhaust system will prevent some of the
burned exhaust gasses from exiting the exhaust
port at the end of the exhaust stroke. This condition
effects the incoming air/fuel mixture on the intake
stroke and reduces engine power
Other signs of advanced ignition timing are engine
overheating and hard or uneven engine starting
NOTE
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