Need help

Discussion in 'Boating and Boat Rigging' started by Smitty03, Apr 24, 2020.

  1. CHASINEYES

    CHASINEYES

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    Did you look down the throat of the carb to see if the throttle plate was perfectly vertical while the shifter was in the wide open position?
     
  2. Smitty03

    Smitty03

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    Not yet tonight I am
     

  3. Smitty03

    Smitty03

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    So I looked at it last night an feel like a momo I actually have a 2 barrel Rochester carb, on further investigation I checked the throttle plate it opens to wot position an closes all like it should, I did take the flame cover off the carb an found out my choke is not opening up all the way once the boat is warm, do I confident that is causing the way it acts after trolling. But for the not hitting over 3900 rpms I do not no
     
  4. Smitty03

    Smitty03

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    Also don’t know if this will change anything but I have a Pertronix electric ignition on it an i am going to change the old coil (original)
    With a flamer thrower 40011 will that help with the rpms?
     
  5. wildcoy73

    wildcoy73

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    Not really. Need to change the pitch on the prop. Basically in auto term that is your final gear ratio, your running to big of a prop to get the top rpm.
    If you read up on it you will see what different pitches will do for hole shot and wide open speed.

    Sent from my SM-N960U using Michigan Sportsman mobile app
     
  6. Smitty03

    Smitty03

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    So which size should I try? From what I read an been told don’t know if it’s accurate maybe you can help out, but I got told that the 15x15 should make the boat scream? Maybe it’s not achieving what it’s capable of due to being a Michigan wheel aluminum prop?
     
  7. wildcoy73

    wildcoy73

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    200 rpms per degree of pitch.
    I would probably try a 17 pitch first.
    The lower pitch number will also decrease speed at times, but increase hole shot.
    Alot of the boats went larger pitch trying to get a little speed
    Se a 15 pitch moves 15 inches per turn
    While a 21 moves 21 inches. That does not include slippage that all have.
    You may be able to find a marina near you that will loan out a prop.
    In addition stainless steel will have better performance than aluminum.
    Sent from my SM-N960U using Michigan Sportsman mobile app
     
  8. Smitty03

    Smitty03

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    I have a 14.5x17 on now steel prop maybe I’ll try get my hands on a 15x15 stainless
     
  9. wildcoy73

    wildcoy73

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    Should get you near top rpms.
    Sent from my SM-N960U using Michigan Sportsman mobile app
     
  10. magnum lure

    magnum lure

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    I would make sure you address this issue as it will cause a RICH condition during motor operation!
     
  11. textox

    textox

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    With limited information i would not assume prop is the problem.I would contact Crestliner and find out what prop came on boat when shipped,build sheet should be on record.If it is original prop(pitch/dia) only then can you know if engine or hull weight is the problem.A good engine diagnosis could tell you of other issues with the engine its self.Might take the guess work out of solving your problem..
     
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  12. kroppe

    kroppe

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    Agree with textox. Too many questions about fuel, spark and air before trying another prop. Questions remain unanswered about the prop also, such as did the boat ever perform acceptably in the current owner’s possession.
     
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  13. textox

    textox

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    Yes Kroppe,Too many systems come into play there,timing,compression,carb tune ,fuel pressure,and the possibility of water in the fuel or a leaking head or more commonly an intake gasket.Lots more to consider than the prop..
     
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  14. Alaby

    Alaby

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    I have a 1986 Sylvan with 4.3Cobra outdrive, I put a pertronix electronic ignition in it. It worked fine at first, then I took it to the Bay. It wouldn't rev over 3000 rpm's. Found out one of the magnets came off , so it was only hitting on 5 cylinders. Put the points back in it and it redlined. That is a glass 19' boat will do over 45 gps mph.
    The magnets are under the distributer cap, a piece of green tape is all that holds them in place,you might want to look there.


    Sent from my iPad using Michigan Sportsman mobile app
     
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  15. kroppe

    kroppe

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    @Smitty03 smitty did you get this sorted?