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  1. #1

    Default Problem With New Tohatsu 3.5

    Hello, I bought a new Tohatsu 3.5 4 stroke for my sailboat about 2 months ago. It always starts right up but after letting it warm up a couple of minutes and pushing the choke back in it struggles to remain idling. If it dies completely, it's almost impossible to start back up. It seems like the engine is flooding but that's just a guess. I always use fresh gas with Sta-bil in it. Thanks for any suggestions.

  2. #2

    Default Re: Problem With New Tohatsu 3.5

    Hi,

    Try adjusting the idle screw on the carburettor. Make sure you note the original position of the screw and count the number of half turns/turns. You'll probably find it'll only take 1/4 turn or so to adjust. Turn the screw clockwise to increase idle speed.

    If that doesn't work it could be the mixture screw so try turning that one aswell but again be very careful to count the turns so you can restore to original position. Try the mixture screw clockwise and anti clockwise to find a point where the engine runs smoothly without the choke.
    Good luck!

  3. #3

    Default Re: Problem With New Tohatsu 3.5

    Quote Originally Posted by shezza250 View Post
    Hi,

    Try adjusting the idle screw on the carburettor. Make sure you note the original position of the screw and count the number of half turns/turns. You'll probably find it'll only take 1/4 turn or so to adjust. Turn the screw clockwise to increase idle speed.

    If that doesn't work it could be the mixture screw so try turning that one aswell but again be very careful to count the turns so you can restore to original position. Try the mixture screw clockwise and anti clockwise to find a point where the engine runs smoothly without the choke.
    Good luck!
    Thanks. Do you happen to know to where these adjustments screws are on this engine? I don't see any reference to them in the manual.

  4. #4

    Default Re: Problem With New Tohatsu 3.5

    Quote Originally Posted by bernieVT View Post
    Thanks. Do you happen to know to where these adjustments screws are on this engine? I don't see any reference to them in the manual.
    No sorry I don't know exact location but should be pretty obvious. They'll be on the carb. Could you post a pic or 2?

  5. #5

    Default Re: Problem With New Tohatsu 3.5

    Click image for larger version. 

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    Looks like idle screw there. Not sure if that's same as your carb?

  6. #6
    Join Date
    Mar 2010
    Location
    Buffalo, NY, USA
    Posts
    2,054

    Default Re: Problem With New Tohatsu 3.5

    You are probably not flooding, but rather leaning out. The 2/2.5/3.5 does require a fairly quick idle to stay running when going into gear (because of low mass of the small single piston), but if it was OK originally, odds are that you did not run the carb dry at the end of each and every day. Because the fuel that remains in the carb bowl leaves a residue as it evaporates, the EPA-required very tiny passages get varnishing in them. Just adding stabilizer does not prevent that issue. At this point, if the varnishing is very minor, you may be able to dissolve it by just running for a long time. Otherwise, you will need to have someone pull the carb, completely disassemble it, and soak it in a cleaner bath for about 4 hours, then blow it out with generic carb cleaner and reinstall.
    Paul
    Buffalo NY USA

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