Hello All,

I am in need of a little professional help. I have a 1993 350l. The other day It was running great. I took it for a ride around the house and pulled back into the garage. This is when it all happened. It was idling fine for a few min when all of a sudden it back fired (sounded like a shot gun going off) I could not get it started. I left it for several days and tried to start again with no luck. The only way I could get it to even pop was to spray starting fluid in the carb. I figured it was a carb issue so I rebuilt it again with no luck. Tore top of engine down to discover a hair line crack in the bottom of the piston skirt. Rebuilt top end with a wiseco piston. Had it bored and matched to the new piston .5mm over. I have great compression 125psi. However the engine will still not start same simptoms. Is it possible that when the engine back fired it took out a crank seal? What else could be the issue. I have good spark, fuel, and compression.

Thank you

 

bump please help

 

Please any help or ideas?

 

If it took out a seal it would be probably on the clutch side. Crack in piston skirt you say? What clearance did they allow? Also even if it does have fire,disconnect black wire from reverse over ride module and check. Keep us posted

 

Thank you for the response old polaris tech,

I am still waiting on new seals and gaskets to arrive. I plan on replacing all outer seals along with water pump seals and gaskets.

Just to clarify, the piston with the crack in it was the original OEM piston. It was replaced with a wiesco piston and ring kit once I found the crack. The clearances were provided with the piston kit and matched to the cylinder. I believe the piston specs from Wiesco said .0015 clearance.

I have already pulled the seals so cant test the reverse over ride black wire. It will be the next test I do if the seals do not fix the issue. I take it this is a known issue with the over ride module?

Have you seen the seals go bad due to a back fire?

I will keep you posted

Thanks again!!!!

 

One thing I did notice while removing the flywheel was a small amount of surface rust on the pickups of the stator. Can I take light sand paper to clean them up?

 

Reverse over ride modules are bad about going out on the older models,can cause backfiring,dying when putting in gear,etc. You can clean pick up surface rust with emory cloth and clean around flywheel.

 

Awesome!! I will clean up the pickups and flywheel during reassembly. I will keep you posted.

Thank you!

 

I think that would do. good luck with it!

 

Let us know how it goes and what you find.