I have a 1999 Mach Z......The PTO cylinder is not firing.....Took the head off....all cylinders look to be perfect...Compression checked and is right where is should be (135 psi)....Cleaned all carbs.....Put all new spart plugs in....There is no weird colors on the spark plugs....What might be causing this to happen?? :cussing:

Is there good spark on that cylinder ?

That is a good point....but before i did all the work to try and find this problem, it had good spark....It keep fouling that plug after 5 min of riding....thats why i got into this was due to that problem

In my experience with electrical - it could act up after it's warm (especially coils), then all together quit working.. Since it's only 1 cylinder, I'd be looking at the coil first.. I'm not 100% sure, but I think if any of the other components were not working, then there'd be no spark on any cylinder.. ??

Thanks for the replys.....Now that cylinder isnt firing...but before it would then foul the PTO plug.....Why isnt it doing the same as before is what i find weird....it should still blow plugs like it did before i cleaned everything...

Anytime something seems weird like that, I suspect electrical. :bash:

Originally posted by Cinch@Dec 9 2004, 10:53 PM
Anytime something seems weird like that, I suspect electrical. :bash:
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Have you tried a new set of plugs or are you just cleaning and re-using the fouled ones? Are you using BR9ES's or BR10ES's? Is the plug gap correct (it should be 0.018"). I've had similar problems before and it turned out to be plugs (popped a a new set in an the problem was gone).

i second other replys. try a new secondary coil. i have had mine also act up AFTER the sled is warm, not on cold startup.i have read before that some machs like odd ngk plugs...not always just the br9es.do a web search on mach spark plug picks. new coil,plug and crank her up to see. i would not go any further into the motor work yet. you may think its a crank seal, but it is probably something more simple. always check electrical first when fouling plugs. then the carb,then the motor.

If there is no spark from that coil, but other two cylinders fire fine, then it's the coil.

Have you yet to check for spark yet, or are you still assuming there's spark, because there was last time you "did all the work"?

To verify if it is the coil just switch any two plug caps and see if the problem moves to another cylinder as they all fire at the 120 degrees so it doesnt matter which wire is on which plug!!!!!!!!!!

I would check the plug cap, try swaping plug caps.

I found the problem with my sled.....Its turns out when u change the gas line off the PTO side and put it on the middle cyl carb, and put the middle cyl. gas line on the PTO side, now that cylinder gets gas.....The engine was jsut rebuilt and maybe it was put on wrong....But does a specific carb need a specific line...You wouldnt think so?? But it solved the problem :cool: