'89 J60TLCE .030 or .035 plug gap?? Any takers?

[rebuilt]

No problems with the motor, thanks to a lot of good advice from this forum. She runs great. Prepping some plugs for a trip this w/e and ran up on the obvious question........ the J/E manual states .030 plug gap, yet I seem to remember somewhere in the posts that .035 is really better. If .035 really is better, why is that the case? Is it that the coils are strong enough to push fire the extra 5 thousandths, making for a taller spark? I just got over a bad case of plug fouling, thanks to trash in the carbs, so if the extra .005 is gonna make them run any cooler, I don't necessarily want that. I tend to run her from 3,000 to 5,000 rpm, and don't like to just idle around. I run it pretty hard every chance I get. It's my understanding and belief that running a 2 stroker like ya mean it is the best for the motor anyway. Thanks in advance, Kevin.

 

[Daviet]

Re: '89 J60TLCE .030 or .035 plug gap?? Any takers?

Set the plugs to .030, thats the way the engine was designed.

 

[rebuilt]

Re: '89 J60TLCE .030 or .035 plug gap?? Any takers?

Thanks, that was my feeling on the issue. J/E came up with those #'s for a reason. KR

 

[JB]

Re: '89 J60TLCE .030 or .035 plug gap?? Any takers?

Actually, plug gap is sort of like fuel mix ratio. They both get "corrected" from time to time. OMC used to specify .030" because the magnetos ran better there. Then someone discovered that the plugs were a lot less likely to foul in low speed operation if gapped at .040". Well, just like the guys who invented 35:1 fuel mix to violate all specifications for fuel ratios, someone decided that .035" was a better spark plug gap than either .030" or .040".

The truth is that an engine with plugs gapped at .035" and running 35:1 fuel ratio will run and survive pretty well, but current "wisdom" says gap your plugs at .030" and run 50:1 fuel mix ratio for best longevity and performance.