Magneto spark

[Dirttracker]

Can the magneto spark get out of time with the flywheel. I can only keep my Merc 500 running with about 20 degrees of timing at idle. The distributor and TDC are correct and compression is good. The carbs are rebuilt, fuel line are new. I checked the dist and it was dirty but not cracked or burnt the rotor button did have a hair line crack running along it but it had not been tracking along it.

 

[JB]

Re: Magneto spark

Need year of your engine, tracker.

If the flywheel key is sheared and the flywheel slipped on the crank it can cause that. Check the flywheel key.

 

[Laddies]

Re: Magneto spark

Also check to see if the flywheel has been taken off at the hub and not installed properly. Put a screwdriver down #1 cyl. and roll it to TDC then check the timing marks.

 

[Dirttracker]

Re: Magneto spark

JB
I think it is a 1975 the S/N # is 4283897 The flywheel key looks fine. I didn't know if the magneto was key differently then the flywheel.

 

[Dirttracker]

Re: Magneto spark

Laddies
The timing mark matches TDC of the piston but the motor will only idle poorly at around 24 degress of timing. The timing belt is timed right according to the little arrow on the dist wheel and and the flywheel when it is at top dead center. I am thinking it should idle better and at a lower timing setting. I thought thayt maybe that the magneto was firing at a different time then the dist timing mark throwing everything off. Other words the magneto has slipped and to compensate for it I have to advance the timing.