1998 90hp force by mercury stalling when shifted into gear


New member
Hi everyone. I’m probably not posting in the correct place because my force motor is a ‘98, after mercury took over. The motor is the exact same thing as a 90 hp mercury 2 stroke from what I can tell. We used to run the 2 stroke mercury’s where I work and when I lift the hood on my force it’s pretty much an exact copy. We are now switched to 4 strokes, so I’m not certain cause it’s been a while. but it looks very similar to the old 2 stroke Mercs.
Anyway on with my issue. It’s a ‘98 2 stroke 90 hp force by mercury. Just had a guy tune it up. He’s a trustworthy guy, so I don’t really think he is ripping me off but he did a regular tune up, new plugs, wires, cleaned carbs, and rebuilt starter. I put it in the water it worked great. I sailed it from where I launched it to my local dock by my house. Probably about 2 miles. When I almost got there it started bogging down like it was losing fuel. I shut it off and realized I needed gas so I put a mixed can in that I had. First off that was totally my bad. I saw the gas gauge and I thought I had enough to make it. You would think after 27 years of working on the water that would have been the first thing I did but for some reason I was too concerned with getting it there cause I had people waiting and I just brought the premixed can “ just incase”. So I get the can poured in and start it back up, everything working fine, and I power to the dock, and when I’m almost there it is bogging down in forward barely running, can’t give it much throttle but I make it to the dock and tie up. Put it in neutral, it runs fine, revs up wide open, but as soon as it’s under load in gear it stalls. And now my starter will barely turn. But that’s completely random. I went down one day and it fired right up, still would stall in gear though. I shut it off and the starter would barely turn the engine. Battery is good, I can wrap a rope around the flywheel and it’ll fire up.
But back to the stalling, I’m guessing I possibly picked up some water or something off the bottom of the tank possibly? I don’t have a fuel water separator, but I have one coming I ordered online. Would that be my stalling problem? I can’t get at the tank, it’s fibreglassed into the hull. I took the carbs off, drained the bowls and made sure floats weren’t sticking, made sure the filter wasn’t plugged. Then I find out that my father mixed the gas and put too much oil in. Would that foul up my plugs? I mean it will run, and like I said rev wide open in neutral, it just stalls in gear. And my starter is most likely screwed again? I think I might just by a new starter and be done with that issue, but I’m stumped on the stalling under load problem. Thank you in advance for any advice.