Whats my best Plug

[dew2]

1988 Evinrude 15 HP,Plugs foul out trolling,Run it wide open then it will troll then foul out.Suggested plugs are Champion L77J4 also listed are the radio noise suppessor QL77J4 and then QL16V.
I am running the L77J4,What plug will help burn the fuel and keep trolling? One of the suggested or one not listed on BPRs site? Thanks

 

[run out]

Re: Whats my best Plug

use autolite # 2643 i had the same problem with champion plugs fouling [part of the problem was my old mtr too] so i changed to autolite plugs and what a big difference. i also torqued them in at 18 foot lbs and gapped them at 35 thou; switch them around the pistons from time to time to burn them more evenly. the mtr started a heck of a lot better too, and if they have them in stock, pick em up at any auto parts store cheaper. good luck.

 

[run out]

Re: Whats my best Plug

Sorry Chief my bad. i re-checked that # and it is 2634 not the one above

 

[Monte1961]

Re: Whats my best Plug

One thing to keep in mind. You didnt say what hp you running. If it's a 25 hp or more, it has been my experience that they dont like long idle and troll speeds. Changing to a hotter plug should help from fouling, but they still will just not as fast. To anyone who reads this post, always specify year, model # and hp. That takes a lot of guess work out of the equation. good luck!

 

[dew2]

Re: Whats my best Plug

One thing to keep in mind. You didnt say what hp you running. If it's a 25 hp or more, it has been my experience that they dont like long idle and troll speeds. Changing to a hotter plug should help from fouling, but they still will just not as fast. To anyone who reads this post, always specify year, model # and hp. That takes a lot of guess work out of the equation. good luck!

I should have known better HaHaHa 15HP.Maybe cause I had 1 hour sleep last night??

 

[watergecko]

Re: Whats my best Plug

Try ngk br6hs or br7hs. I use them on my '76 15hp and '89 25hp and get significantly smoother low speed operation with no fouling. Although many johnnyrudes are quite picky about liking ngks. two identical motors, one may like them the other not.