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  1. #1

    Default 1986 Evinrude 25 with a hitch in its step...

    First, many thanks to all of you who have contributed to this resource. I have a 1985 Evinrude 25 that came with a Boston Whaler I purchased. The engine needed work and with searches from this and other pages I have:
    1- cleaned and rebuilt the carburetor
    2- installed a new starter
    3- link and sync
    4- Joe Reeves WOT timing
    The spark appears strong jumping 7/16ths easily and brightly.

    The engine has an occasional miss that occurs at low and high power settings. (Apologies for the camera work)

    Low Speed Miss:
    https://youtu.be/tgJc2TComoY

    High Speed Miss:
    https://youtu.be/OMw00Bv2EAg


    Where should I look to fix this?
    Thank you,
    Stephan Sloan

  2. #2

    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Check out OM fishing on youtube, he did a retune with info from a service bulletin for his 30hp someone gave him on doing the link sync for low speed lean coughs.You could have multiple problems.Never know with these old motors.Fuel pump, plug wires,coil dropping out.Have you checked for any air leaks.I just found one in my 20hp 1985, but it did not behave like yours.You can spray carb. cleaner or something around hoses or gaskets or primer and see if engine changes idle speed. I found a leak at the fuel pump gasket.Caused lean at slow speed/idle.Spark may be strong sitting still or in garage but drop out as you get it going on water.Good luck.Let us know if you resolve it.My motor is like yours so it may help me some day.
    Last edited by newyota; 07-20-2018 at 12:26 AM.

  3. #3
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    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Exactly how did you do the sync and link? With the engine off in forward gear clip a alligator clip with a straight wire on the throttle shaft of the carb. Slowly advance the timing until the wire just begins to move the line on the throttle cam must be center of the roller at that point. Double triple check the wire just begins to move at that point. Then loosen the collar on the link rod and take it WOT. With one finger hold the carb fully open and push the collar up tight to the pivot pin and and tighten the screw in the collar. That holds the carb fully open at WOT

  4. #4
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    Default Re: 1986 Evinrude 25 with a hitch in its step...

    The low speed cough sounds like its loading up or too much fuel and the high speed sounds like its too lean. Do you know the high speed jet size is it possible the motor was set up for high altitude operation?
    Last edited by kimcrwbr1; 07-20-2018 at 02:25 AM.

  5. #5

    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Kimcrwbr1- I agree that it sound like too much fuel down low and maybe lean at high speed.
    I'm going to try another gas tank as I don't like the WestMarine stuff and may also cut out the transom mounted fuel filter.
    I did the link and sync as best I could and was thinking that because I was getting good idle and good full throttle rpm I had gotten it close enough.
    I do not have a service manual and believe I'm looking for 30 deg. timing. So I did the Joe Reeves method at 26 deg.
    Best,
    Stephan

  6. #6
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    Default Re: 1986 Evinrude 25 with a hitch in its step...

    If you did not mess with the max spark advance it should be good. Every time you pull the carb you must check throttle pickup or sync. With a alligator clip and a straight wire you can get it exact. Just clip the wire to the throttle shaft on the carb, the throttle butterfly should just begin to open as the mark on the throttle cam passes center of the follower roller.

  7. #7
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    Default Re: 1986 Evinrude 25 with a hitch in its step...

    One of those gas welding tip cleaners works good for cleaning the high speed jet. A soft copper wire works good also just pull the plug on the bottom of the float bowl and run the wire into the jet and wiggle it around as you push in and out.

  8. #8
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    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Youcan get a aceteline torch tip cleaner for around $5 at home depot.

  9. #9

    Default Re: 1986 Evinrude 25 with a hitch in its step...

    I did remove and clean the carb. Because I do get sustained operation at high RPM I am thinking it is not clogged. Am I wrong?
    Stephan

  10. #10
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    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Is the sync correct?
    did you pull and clean the high speed jet?
    there is a big difference between cleaning and rebuilding a carb.
    did you replace the float needle and seat?
    is the float set properly?

  11. #11

    Default Re: 1986 Evinrude 25 with a hitch in its step...

    I believe the sync is correct. The carburetor was disassembled cleaned with carb cleaner and then each part was dunked and cleaned in an ultrasonic cleaning tank. I purchased a carb rebuild kit and replaced the float, needle and seat all gaskets and knock-out plugs. I set the float to parallel.

    With the engine making full power what is it about the cough that makes you think it's a carb setting?

  12. #12

    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Hey there. You said that you set the float to parallel. There is also another setting. If you hold the carb upside down the float should be hanging at a certain distance from the bowl of the carb. Mine was 3/4” I think. There is a little tab on the back of the pivot point. Read the directions in the kit to get your measurement.

    The cleaning thing...I couldn’t see the stuff in mine but cleaning them out made a huge difference on my engine.

  13. #13
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    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Until you confirm engine sync is correct your spinning your wheels you cannot properly set the slow needle.

  14. #14

    Default Re: 1986 Evinrude 25 with a hitch in its step...

    Ok- Please see below for what I understand from your directions on setting the sync. I put a wire on an aligator clip on the throttle shaft on the carb it is the silver wire next to the starter on the right hand side. I think you will see that it begins to move as the cam passes the mark.

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