# tecumseh ignition coil on 6.5hp engine



## WildcatKY (Sep 28, 2012)

Anyone - Is it possible that an ignition coil can check out okay with good spark when cold, and fail once mower reaches operating temp? Doesn't make sense to me, but I think I have read somewhere that it can. Thanks all.


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## finaprint (Jan 29, 2006)

Yes. 

The heat swells up coil windings to then touch/short at a rub spot from vibration. Anything electronic firing that coil can do the same thing but for a different reason.

As well, any small cracks on the outside case can be small enough to pass over or disregard as harmless when they are not. Humidity leads to moisture getting in and then the high voltage of the secondary shorts windings due to the moisture having corroded on an almost microscopic level but it doesn't take much, secondary winding wire is very thin and fine. The coil then works fine until hot then faults in 50 different ways. 

I drive 2 ford Focus cars and the compact motorcycle-like coils on them fault like that left and right, the most common ignition failure on the cars. You change coils on them faster then you do plugs for sure. I've had new ones fault in less than 6 months and all you see is a very miniscule short hairline crack in the plastic case, the evidence of bad. 

I have repaired cars, bikes, and lawn equipment for 40 years and there are a lot of ways coils can go bad, and almost different symptoms every time they do.


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