I have a 2002 90hp 2-stroke Johnson on a pontoon & the motor jumps. I have not had the boat long & this is teh first time i have really been able to run it for a long time. It feels like I hit something with the foot as I’m going across the water. It seems to only happen a 10mph or higher. If I keep speed at 15-20 & hold that it does not happen very often but when I get over 20 it seems to happen more opten. It also happens when I adjust the tilt & trim as I am moving along at higher speeds. I usually keep it trimmed all the way down & seems to happen less then.
I had some older gas in it so I ran it as low as I could then filled up with mid grade ethenol free & ran it out & still doing it. Prop seemed a little loose so I tightened nut one round & still doing it.
Could it be a bad prop, gas issue, or could the motor mount part of the pontoon be flexing & making it feel like the motor is hitting something.
Any help would be appreciated…
had the exact same issue with my 150 Merc 2 stroke last summer. Rented a house with dock at Edisto with the intent of fishing day and night. First day out, as soon as i tried to get on plane, the motor jumped like the prop was missing a fin. Didnt get to do much fishing needless to say. Anyway, ended up taking it to the shop when I got back home, turns out had an issue with one of the ignition banks. The left bank was shot and not firing correctly. $500 later, all was well. Hope that helps.
Your issue sounds more like a timing issue. I hope not, as the ignition system on these motors is not cheap.
Power pack, my parents have a 2000 model on their pontoon boat. At low speeds it idles fine and when you tried to run it would skip like crazy. Very easy to replace and cost about $130.
It doesn’t skip all the time. Just here & there but does it more often at speeds over 20mph or when you mess with the tilt & trim running at faster speeds, or as you are gunning it to pick up speed sometimes. Strange…
I had some one look back at the motor & when it did it they said teh motor actually did “jump” as if I hit something floating in teh water.
Curious as to where you found a power pack for $130. All I have seen is $230.