Engine is idling rough then coughs and sputters and dies. Starts fine and runs perfect above say 1000rpms. Below that it seems to be missing. Boat will start and run on #1 and # 3 cylinders by themselves. Wont start on #2 solo.
So far I have replaced the fuel pump. I swapped out coils to #2 cylinder with no change. Carbs were redone last year so I took apart #2 carb and cleaned it and everything looked perfect. Also swapped out plugs with no change. boat has new plugs and fuel filters as well.
What else should I try? Any suggestions on what it could be?
Get It!
sounds just like mine!! It does the same thing, stalling at low rpms then starts right back up. It’s also been smoking a little when cold starting. I was thinking it’s just running too lean.
Don’t know a lot about working on motors, but I do know my 2001 motor was running, but I lost compression on one cylinder. I replaced motor and still have the other on for parts. I also have a 2006 2 stroke 90 yamaha for sale with less than 80 hours. If its not dirty carbs or spark plug, maybe check compression?
start with compression test
if compression is okay, add a little fuel to that cylinder and see if it runs better
have you checked for spark on that cylinder?
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