OK, so I converted my little Johnson 1996 25hp 2 stroke 3 cylinder to a 35 HP this past year. As part of the conversion we put 35 HP jets in the carbs., went from the stock 25 HP low speed jet #31 to a #32 and high speed jet from #36 to a #38. Should I bump them up (drill them out) a little more? Not sure where the limit is or at what point your flirting with disaster. My buddy has a set of "jet bits", old mechanic!
I should probably just leave it alone!
Pull the spark plugs after a good run and a quick shut-down. If the plugs are a nice chocolate brown, leave everything alone. If they are a grey-white, better open the high speed jets up a little (engine is running lean) . You may also look at the piston tops to see if the engine is running lean/rich. Opening the idle jets actually leans the engine at ldle as these jets are controlling air intake. The high speed jets control fuel intake. I would recommend replacing the jets as preferable to drilling. You can learn much on the internet by typing in "reading spark plugs". Hope this helps you a little. I didn't know OMC ever made a 3 cylinder 25 hp engine.
They did, but I've never seen one.
Jeff
Thanks for the "eye opener" . I would have never guessed! Rod