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  1. #1
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    1985 Evinrude 300 wont rev out

    Good evening, I have a 1985 evinrude 300 with the blue insert land and sea heads. I have been running a 21 pitch prop. I am located in Denver, CO. The boat will rev right up to 4500rpm and then slowly rev to around 5200 and stops reving. I have boysen reeds, new cdi coil packs and voltage regulator. I have deleted the VRO. Is there some electronic that would limit the rpm because of the vro being un plugged? I cannot figure out why it won't turn that small of a prop. Boat is a 21' Sanger Alley Cat
    Thanks
    Last edited by summitrider1; 08-25-2018 at 09:43 PM.

  2. #2
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    What's your elevation up there? Gotta be close to 6000' ASL? Not only will you need a smaller prop due to lower power output, the carbs will need to be adjusted to run at that elevation as well. Any idea what jets are in the carbs now?
    Keith-

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  4. #3
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    It currently has 78d jets. It came with 83d jets when I bought it. Yes somewhere just below 6k feet.

  5. #4
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    I have looked at plugs and they don't look overly wet. I would think that this motor would have no problem spinning a 21 pitch prop to 6k rpm at this altitude. It pulls extremely hard to 4500rpm about 45mph and then slowly goes up. I resynchronized the carbs and linkages last night, im going to check timing on the motor this weekend. Any other things I should look at? Could it be a stator issue? I have tried calling and emailing monte racing for the last few weeks but haven't gotten a response yet.

  6. #5
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    I'd wait for some input from some of the other builder/tuner guys that have done altitude stuff before, but I know in the automotive world, you can generally add about 2* of timing per 1000' elevation. 2-strokes might be a bit more sensitive to that though. Cylinder pressures will be lower due to lower atmospheric pressure, so adding timing helps.
    Keith-

  7. #6
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    how high is the prop shaft?

  8. #7
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    The motor does have a hydraulic jack plate.

  9. #8
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    Click image for larger version. 

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    Last edited by summitrider1; 08-25-2018 at 08:55 PM.

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  11. #9
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    From pix motor too low... get a 24 raker and bring it up 4 inches......Allys are full tunnel so the prop sees all water. But the RPM drop says you have problemes... sorry no spell check. Call RACER....

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