Engine Backfires, Cuts Out Or Misfires During Acceleration; Engine Backfires On Deceleration - Hisun HS700UTV-4 Maintenance Handbook

8. Contaminated or stale fuel.
9. Clogged air filter.
10. Intake pipe air leak.
11. Plugged exhaust system. Check the silencer or muffler, especially if the utility terrain vehicle was
just returned from storage.
12. Faulty ignition system component.

Engine Backfires, Cuts Out or Misfires During Acceleration

A backfire occurs when fuel is burned or ignited in the exhaust system.
1. A lean air/fuel mixture can cause these engine performance problems. Check for the following
conditions:
a. Incorrect float level adjustment.
b. Plugged pilot jet or pilot system.
2. Faulty accelerator pump.
3. Loose exhaust pipe-to-cylinder head connection.
4. Intake air leak.
5. Incorrect ignition timing or a damaged ignition system can cause these conditions. Perform the
Peak Voltage Tests to isolate the damaged ignition system component. Check the ignition timing
as described.
6. Check the following engine components:
a. Broken valve springs.
b. Stuck or leaking valves.
c. Worn or damaged camshaft lobes.
d. Incorrect valve timing due to incorrect camshaft installation or a mechanical failure.

Engine Backfires on Deceleration

If the engine backfires when the throttle is released, check the following:
1. Lean throttle pilot system.
2. Loose exhaust pipe-to-cylinder head connection.
3. Faulty ignition system component.
4. Check the following engine components:
a. Broken valve springs.
b. Stuck or leaking valves.
c. Worn or damaged camshaft lobes.
d. Incorrect valve timing due to incorrect camshaft installation or a mechanical failure.
GENERAL INFORMATION
The ignition timing is controlled by the ICM and
cannot be adjusted. However, checking the ignition
timing can be used to diagnose problems.
NOTE
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