Spark plug gap

[chas451]

Just installed new Champion L77JC4 spark plugs in a 1988 Johnson 70 HP. Champion calls for the gap to be set at .030" but the Clymer manual says to use .040". I understand the wider gap will foul less when trolling and the smaller gap best for high speed. Does that mean that using .035" gap would be the best all around setting? Anyone have any ideas on this?<br /><br />Thanks, Chas

 

[bubbakat]

Re: Spark plug gap

I run mine at 40 but you could set them at 35 I don't see any prob. with it.<br />One way to find out is run it a day with each of the settings and see what suits you.

 

[rickdb1boat]

Re: Spark plug gap

And you should be using QL77JC4 suppression plugs with that motor. Not just L77JC4.