1992 J70TLEND Puzzled

[jasperdog032469]

Ok, like most people on here, I'm about to pull my hair out!!! lol!

I have a 1992 J70TLEND. My problem is that the bottom cylinder is not working properly. It seems to be firing fine now, put on all three new ignition coils and a new power pack. When I place my hand over the bottom carborator, it does not kill the engine, likewise when I spray starting fluid in, it changes nothing. The other two cylinders respond to both, and seem to run fine. Running compression is same in all three, as well as standard compression is the same on all three..140lbs. I checked the reed valves, and they seem to be in good shape. All three carbs have been rebuilt. ?????? We even switched the top and bottom carborator, and the same problem still occurs at the bottom cylinder. Any guesses?????
I hate to take it to the shop.

Dave

 

[CharlieB]

Re: 1992 J70TLEND Puzzled

The ignition trigger may not be working, triggering the module to fire # 3

I didn't notice if you had checked spark.

 

[CharlieB]

Re: 1992 J70TLEND Puzzled

Or the lower main seal could be bad, allowing that cyl to suck air and blow enough of each intake charge out into the exhaust that the cyl will not fire.