NetDoc
Chief Petty Officer
- Joined
- Aug 20, 2011
- Messages
- 517
Re: 3L Runs On/Dieseling
Dieseling is a sign of overheating of the combustion area. This could mean that the engine is running significantly hotter, leaner or too advanced. Have you checked for a vacuum leak yet? That could really heat up the combustion chamber and cause the hunting you are complaining about. There are a few ways to do this, and you should pay attention to the throttle shafts in the carb as well as any gasketed areas (manifold and carb). 4 spark plugs are relatively inexpensive and easy to change. The colder spark plug just won't self clean as well if there is any oil consumption. I say it's worth a try as it may be the ignition source once the spark has been removed from the combustion chamber. As a temporary work-a-round, you might floor the accelerator AFTER you turn it off. The sudden over abundant supply of air often quenches the hot combustion chamber to stop the dieseling. This is only a stop gap method and you should identify and fix the problem rather than rely on this.
As for setting the engine speed higher: that will make this condition WORSE. The lower the better. The richer at idle the better, especially if you idle for a minute or three before you switch off.
Final note... change your gas. Go for a higher octane which will burn a bit cooler. It won't give you quite the economy as the cheap stuff, but it may rectify your problem.
Dieseling is a sign of overheating of the combustion area. This could mean that the engine is running significantly hotter, leaner or too advanced. Have you checked for a vacuum leak yet? That could really heat up the combustion chamber and cause the hunting you are complaining about. There are a few ways to do this, and you should pay attention to the throttle shafts in the carb as well as any gasketed areas (manifold and carb). 4 spark plugs are relatively inexpensive and easy to change. The colder spark plug just won't self clean as well if there is any oil consumption. I say it's worth a try as it may be the ignition source once the spark has been removed from the combustion chamber. As a temporary work-a-round, you might floor the accelerator AFTER you turn it off. The sudden over abundant supply of air often quenches the hot combustion chamber to stop the dieseling. This is only a stop gap method and you should identify and fix the problem rather than rely on this.
As for setting the engine speed higher: that will make this condition WORSE. The lower the better. The richer at idle the better, especially if you idle for a minute or three before you switch off.
Final note... change your gas. Go for a higher octane which will burn a bit cooler. It won't give you quite the economy as the cheap stuff, but it may rectify your problem.
