Prop Slip

Discussion in 'Bubba's Outboards' started by BAM, Dec 29, 2005.

  1. BAM

    BAM New Member

    Messages:
    827
    State:
    Tennessee
    Mr Bobpaul, Is there a way to check a prop to make sure the hub is not slipping?
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    I hope he dosen't mind me trying to help with this.

    Take your prop off and take a magic marker ( water proof one perferred) and make you a mark from the inside of the hub where the shaft comes thru to the outer edge of the prop housing. Should be a hub where the shaft fits and rubber bushing and then outer hub.
    Reinstall prop and take out on the water and run. If it slips then the marks won't be lined up.

    One good sign of of prop slip is you will get an increase of engine rpm's but less forward motion.
    Bam if your prop is sliping let me know and I can give you a mans name that has a prop shop over in soddy daisey and he is good and reasonable to. You can normanly rehub a prop for about half the price of a new one.
     

  3. BAM

    BAM New Member

    Messages:
    827
    State:
    Tennessee
    Thanks Bubbacat, don't know why I didn't think of that. DUH Will give it a try tomorrow.
     
  4. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    If it is just get a new rubber hub prressed in and ready to go again. But Bubbakat is right mark it and then check it.
    Pete

     
  5. Bobpaul

    Bobpaul New Member

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    Good info guys. I never mind good help or input in this section.

    Another indication of a slipping prop is some grains of rubber on the inside where the hub meets the prop.

    All the slipping props I've ever seen, won't let you get past trolling speed, but the engine will over rev.
     
  6. BAM

    BAM New Member

    Messages:
    827
    State:
    Tennessee
    Thanks BP, the boat will get up on plane and run good but cant run about 3/4 throttle or RPMs get to high. Current prop is a 13x21pitch, tried a 23 pitch RPMs at WOT was below 5k. If Current prop is not slipping will try a larger dia. 21 pitch. Thanks guys
     
  7. Bobpaul

    Bobpaul New Member

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    Bam, it sure sounds like you need more pitch than a 21. The larger Dia, might help, or get your 21 pitch cupped to add a bit more resistance and not go to a 23 pitch.
     
  8. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    Buck you can try one of the 4 baldes props. They will take moer to turn. I think my Johnson lost aorund 800 RPM with the 4 blade composit props.
    I need to drop down to a 19 on the 140 Suzuki, The 21" is only turning 5200 and the motor is rated for 6200. But sure like the light fuel usage with the 21"
    PEte
     
  9. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    I agree with bopaul on this. A cupped 21 would more then likely keep you within your rpm range and give you good bite and fuel efficiency.
    Bam tell me what you are running there and estimate load and we might just figure it out for yea.
     
  10. BAM

    BAM New Member

    Messages:
    827
    State:
    Tennessee
    Thanks Guys for the replies. Prop is slipping, was more noticable yesterday. The marks were not lined up when I got back. So I will be off to the local prop shop monday to get the situation fixed. Thanks again guys
     
  11. Bubbakat

    Bubbakat New Member

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    4,532
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    McMinnvill
    Awh another happey fisherman. Good deal Bam. Thanks for letting us know. :)
     
  12. Bobpaul

    Bobpaul New Member

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    And if you don't quite like it after it's rehubbed, get it cupped :)

    Happy New Year Guys!
     
  13. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    BobPaul
    I'm running a 21" on the Suzuki 140 4-stroke. And it only turns 5200 rated for 6200. Will the 19" let it turn over the 6200? I like the 21" now for the fuel. But its getting burn marks on it..Where its slipping its a three blade alumiunim porp.
    May go to a SS later on.
    PEte

     
  14. bearcat

    bearcat Member

    Messages:
    925
    State:
    Nokomis, Illinois
    Hey Bob correct me if I am wrong. Doesnt a drop of pitch on the prop add around 400 to 500 rpm and an increase in pitch decrease the rpm by around 400 to 500 rpm.

    I know when I changed props on my boat that is what happened.
     
  15. Bobpaul

    Bobpaul New Member

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    Yup, that's about right. It could be as much as 800 rpm's depending on the running condition and hp of the engine.
     
  16. Bobpaul

    Bobpaul New Member

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    Pete, if your doing 5200 and it can run at 6200, I'm thinking your straining the engine and loosing gas per hr.

    The 19 should get you up to or nearer the 6200 rpm's, and if it goes over, getting it cupped will help to hold the rpm's closer. You should get a better hole shot with the 19 too.

    If your prop's getting burn marks, you might try slowing down in the turns. I've seen cavitation burns on big hp Yamaha props and you can't really turn those boats with a 200 really fast, so it just might be the nature of your set up to burn the prop a bit.
     
  17. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    Thanks BobPaul. Most of the times I only run around 4000 RPM's and the hole shot is great as it is. But I do think I will move to a 19" prop.

    I bet that is where the burn marks are coming from. But then again the most turns I make most of the time is on bends on the river.
    So looks like I will be getting a 19"
    Pete

     
  18. Bobpaul

    Bobpaul New Member

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    Pete, let us know how it turns out.