u/j-rock_Snow

▲ 4 r/Outboards+1 crossposts

2007 OptiMax 90 rough idle

Looking for some insight here. My OptiMax seems to have an intermittent missfire. At idle and higher revs. Compression 120/115/120. See photos for brand new spark plugs after 10 minutes at idle. 1-2-3 from left to right. Video shows cold start and cutting out. After it does that it idles continuously but still seems to miss - but doesn’t die. It seems like after it warms up a bit it keeps on going, but the hesitation / missfire is concerning to me.

I pulled each plug cap off one at a time and it dies when I do that…. So spark seems good to me. I also pulled each injector connector in the same fashion….. dies when I pull each one. Fuel pressure is over 100 psi (current gage only goes up to 100, waiting for new gage in the mail) and air pressure is 92 psi.

I do have a whole new fuel rail as a spare, wondering if I should replace the air regulator? My 100psi gage seemed like it was showing probably 110 psi fuel psi so my guess is air is low??? But hard to tell.

Any thoughts?

*** spark plug photos in comments. Can’t attach photo and video at same time

u/j-rock_Snow — 1 day ago

Oil on drive shaft

After changing oil on my 2007 Mercury 75HP EFI, I pulled the lower unit to change the water pump. I ran the engine on muffs after the oil change and before pulling the lower unit. I noticed fresh oil on the top of the drive shaft (see photo). Does this concern any of the experts out there? Do I have an issue???

TIA

u/j-rock_Snow — 2 days ago