Robin EY15 - Engine Knocking Causes; Engine Backfire Troubleshooting

11-5 ENGINE KNOCKS
1) Low-quahty gasoline.
2) Engine operating under heavy load at low speed.
3) Carbon or lead deposits in the cylinder head.
4) Spark timing incorrect.
5) Loose connecting rod bearing due to wear.
6) Loose piston pin due to wear.
7) Causes of engine overheat.
11-6 ENGINE BACKFIRES through CARBURETOR
1) Water or dirt in gasoline, or low-grade gasoline.
2) Intake valve stuck.
3) Valves overheated, or red-hot carbon particles in the combustion chamber.
4) Engine cold.
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