27 HP PRO-DRIVE Engine surging

Discussion in 'Mud Motors' started by TxDuckman, Dec 4, 2016.

  1. TxDuckman

    TxDuckman New Member

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    Dec 20, 2015
    My engine was running fine until I ran over a sand flat at WOT for 200 yards, motor bouncing off bottom, then started surging to the point it would die at idle, but would smoothe out at WOT. Disassembled and cleaned carb. (Nikki). Checked all fuel line connections. Plugs are burning clean (light tan color). Put on a new fuel pump because I had one. Still surges, but smoothes out at WOT.
    Any ideas would be aprec
     
  2. GoodYr09

    GoodYr09 New Member

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    Feb 13, 2009
    Location:
    Iowa
    Sounds like the intake around the carburator is sucking some air. Therefore the carb is not controlling the air fuel mixture, it just revs up and down.

    Look for a drop dripping from around the carb. I have a mikkuni and saw the drop if gas drip off. took it iff, cleaned ut up, alcohol based carb or brake cleaner, (spray stuff), got that yellow gasket sealer in a tube. Replaced the rubber grommet that goes between carb and intake, tightened it up, night and day diff.

    Sounds like yours is a stock motor. Get a guy who works on small engines or a briggs dealer, they are usually pretty good. Something is not tight in your gas/air intake, with my limited knowledge. Get it fixed quick, it will tick you off and you will start to not like your motor etc. Its simething simple, but its not simple to find it, I understand your issue. Post back when you get it running good again.
     
  3. Olefart

    Olefart Senior Refuge Member

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    Non CDI motor with Mechanical governor ? If so governor Idle spring may have fell off.
     
  4. TxDuckman

    TxDuckman New Member

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    Dec 20, 2015
    Found the problem. I had installed a fuel shutoff valve before the pump 2 years ago, the ball inside broke away and was tumbling like a vortex inside, so I think that when the hole was aligned with the line,it would get fuel. Removed the valve, then fired right up and ran good to 3,900 rpm.
     
  5. bang you'r dead

    bang you'r dead Canada Forum Mod. Eh! Moderator Flyway Manager

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    Good work. Last thing you need is to lean the thing out at high speed (sounds good and runs great) just before the pistons melt and you paddle home. Been there and done that with a snowmobile...twice. Once was a partially closed fuel shut off valve, and I didn't change the jets when the temp dropped to -30. Could have retarded the timing, but wheres the fun in that...........boom........(sound of walking home in the snow at -30C insert here)
     
  6. TxDuckman

    TxDuckman New Member

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    Yep, didn't need that. I turned the engine off and trolled/push poled 5 miles back to the ramp, took all night to get back. Hunt ended before ot started on 2nd opener. Least I didn't burn a piston.
     
  7. TxDuckman

    TxDuckman New Member

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    Thanks guys for the info.
     
  8. GoodYr09

    GoodYr09 New Member

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    Iowa
    You paddled/push poled back 5 miles in the dark. Holy crap, on the 2nd opener. Doing that and missing the hunt had to be painful, but your still hanging in there. Sometimes I think duck hunting is a disease, all the work, lost sleep, and frustration we go thru. Great job on finding the problem.
     

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