QL78yc vs. L77jc4 sparkplug for '94 Evinrude 60hp, E60TLERV

[nautihabits]

Bought the referenced motor and it came with QL78YC champions. The manual calls for L77JC4 plugs. Seems to be running OK. Use the boat for recreational purposes. Any advise on what I should be using?

 

[Dhadley]

Re: QL78yc vs. L77jc4 sparkplug for '94 Evinrude 60hp, E60TLERV

Welcome!!<br /><br />I dont think I'd run the 78's because they are a bit hotter and with the longer reach bring the flame closer to the piston dome. Not a good situation especially if the motor is being lugged at all. Or if youre using something other than 87 octane.<br /><br />We'd like to see the motor set up for 5800-6000 rpm with an average load for long life. The QL77JC4's would be the best choice.

 

[nautihabits]

Re: QL78yc vs. L77jc4 sparkplug for '94 Evinrude 60hp, E60TLERV

Don't know what "lugged" is? but thanks for the info. The 78s are coming out. Running 87 octane on a 16'7" whaler newport.

 

[Dhadley]

Re: QL78yc vs. L77jc4 sparkplug for '94 Evinrude 60hp, E60TLERV

That motor will live the longest if its set up at 5800-6000. If its at say, 5200, the combustion temps are higher than they should be. That leads to sticking rings. The closer you get to 5800 as the top rpm, the longer it takes for the rings to stick.

 

[nautihabits]

Re: QL78yc vs. L77jc4 sparkplug for '94 Evinrude 60hp, E60TLERV

Thank you so much, is that a 30 gap.