What spark plug to use?

[wordmaster]

I have 1982 Evinrude 90, E90TLCNB. I have read that I can use a UL77V centerfire plug and also that I can use a L77JC4 regular plug.

I do a lot of idle speed trolling. Of course I also do a lot of full speed running. I am pushing a 24 foot pontoon boat. Will the UL77V be worth while, or should I just get the regular plugs. A smooth long idle is very important as I catch most of my fish this way.

Any and all help greatly appreciated. Thank you

 

[joereeves]

The proper spark plugs to use would be Champion QL77JC4 plugs. The original recommended gap was .040 but that was changed at some point in the 1990's to .030 . The differnce being that one gap or the other might prove to be the better choice pertaining to idle (trolling) or full throttle running. Try both gaps for performance.

 

[jwbmarine]

i dont use surface gap,.....for a lawnmower......use what joe said

 

[wordmaster]

Thank you. I will try this plug and split the difference with a .035 spark gap and see how it does.