Plug gap 1990 Johnson 30 HP

[Johnnielund]

I have a 1990 Johnson 30 hp motor. According to the OMC service manual the recommended spark plugs should be either QL77JC4 or L77JC4 gapped at .030.<br />After speaking with Bombardier tech support I was told that QL82JC4 gapped at .030 should be used if there would be extended idling. I have also heard from some OMC techs that the gap should be .040. Bombardier says they have no technical bulletin reflecting the change from .030 to .040. Can anyone offer some information on the proper gap and why?

 

[JB]

Re: Plug gap 1990 Johnson 30 HP

Hi, Johnnielund.<br /><br />Many of the old OMC manuals call for .040, but they put out a Service Bulletin in the 80s that said to change to .030.<br /><br />The "standard" has been .030 since then.<br /><br />Good luck.