My 1982 evinrude came with UL77V gapless plugs. It starts and idles fine but the motor vibrates bad at idle speed when in gear but smooths out after adding a couple hundred more rpm. The plugs were all oil fouled so I changed over to QL77JC4 which came gapped at .030. I have read on forums that the gap was originally .040 but omc changed it over to .030 in the '90's. Was this just for newer models with upgraded ignitions? So, what should the gap be for this 150hp 1982 evinrude?
