Don't have a manual in front of me or easy access to one at the moment but typically there's a sticker on the engine that mentions what the plug gap should be.
What gap? Merc uses surface gap plugs in most of the engines I have owned and they are the recommended plug in the manual. If you are running a gapped alternate plug also listed in the manual the gap is on the order of 0.040" but don't quote me on that. Some CDI's are up to 0.060, not necessarily marine 2 strokers.
Aren't surface gap plugs best for outboards, like NGK surface gap plugs, they say there better for heat. What plugs are in the motor now? If there surface gap I would got to NGK website and find your plug,and return the gapped plugs.
Aren't surface gap plugs best for outboards, like NGK surface gap plugs, they say there better for heat. What plugs are in the motor now? If there surface gap I would got to NGK website and find your plug,and return the gapped plugs.
I had surface gaps in OMC and Mercs. On my late 1980's Merc 115 tower, I went 7 years on the same set of SG, NGK plugs. Yes I didn't go out every minute I had off, but I got a lot of use out of them. Engine started right up, ran out at 6k rpm ("on the pad") at WOT, smooth as silk, why change them? Yes they had carbon streaks on them but that's what the 40kv (open circuit) Merc CDI ignition was all about.....firing plugs regardless of their condition.
