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  1. #1

    Default 90hp Merc ELPO bogs under load

    I took our pontoon boat with a 90hp Merc. 2 stroke outboard out for it's first Spring run and it kept dying under load and was hard to re-start. I assumed there was water in the gas as the tank was left 1/2 full, so I added drygas and filled balance of tank with fresh gas. It started a little better and idles in gear OK, but when I call for any more speed/power, it just stalls/bogs down; re-starts fine. What's more likely, dirty carburetor/chokes or fouled plugs? I'm not familiar with 2-stroke outboards, but am familiar with 2-stroke snowmobiles; that's why it seems like either fouled plugs or dirty/sticking chokes - however, neither ever seem to stall/kill the motor in a snowmobile. Please help!! Thanks!!! Nelson

  2. #2
    Join Date
    May 2013

    Default Re: 90hp Merc ELPO bogs under load

    Nelson I know nothing of your rig other than the comment above. So as a general answer from the owner of the same engine: You answered your own question. My solution, and ask a hundred people and you'll probably get that many different answers, to really solve that problem get rid of that tank of fuel. I doubt you'll get satisfactory performance continuing to dope up bad fuel with additives.

    Then get a few cans of Sea Foam (at most automotive stores, white can red label) and read the label. It says 1 oz per gallon of gas is the maintenance dose but for your initial run after you get new gas, I'd use at least 2 oz per gallon. It won't hurt anything as the engine can run on it....when troubleshooting if needed. I learned of it on a site such as this and since using it I have had zero fuel problems.

    The SF will clean up your fuel system and get rid of any residual goo that may be there from prior operations over the years. Until you have given this solution time to clean things up, I wouldn't touch a thing IF your engine was running to suit you last season. You probably will clean things up to suit you on your first outing. Usually takes awhile, 30 minutes or so for the SF to get in and start working.....if you have crud it takes a little time to dissolve it. So load up and just putt around enjoying the scenery till it clears up.

    Then when you finish for the season, ensure you have your tank topped off and a fuel stabilizer like Stabil or just use Sea Foam. States on the can it's a fuel stabilizer.

    If it doesn't clean up then more drastic measures can be implemented, but you will need a manual for that phase.


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