Thread: Prop blow out?

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  1. #1
    Member TheRubberDuck's Avatar
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    Prop blow out?

    All, I don't know if prop blow out is the correct term...

    2018 SDC with a 250 proXS two stroke on a 14" manual jack plate. 3/4" below pad

    I have been trying to run a 28 4 blade bravo. It has 4 PVS plugs. The hole shot is TERRIBLE! I've tried with all plugs, without plugs, half/half. About the time the nose of the boat gets up and the boat feels like it should take off, it feels like the prop blows out..... Or like the old school props, it would be slipping. I have to feather the throttle just to even get it to break over.

    Today, I tried a 26 4 blade bravo, 2 plugs out, 2 in. The hole shot seems like its about to be soooo much faster like you would expect, but then it blows out. The motor is trimmed all the way down every time.

    Is my motor too high on the jack plate? This issue is driving me crazy. It doesn't seem to improve with any combo of PVS plugs. Any info or suggestions is greatly appreciated. I'm still all new to the Bullet world, and this is my first boat since the late 90's. Thank yall
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  2. Member
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    #2
    Call Mark at http://www.marksprops.com/

    I had the same issues when I changed from an old 200EFI to the 250 Optimax on my 21XD. I was sick of my change until I got with Mark.

  3. Member
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    #3
    Motor might be to high. My fishing/tournament partner has a 2017 SDC with 250 2 stroke also. He runs a 28 Bravo xs with four holes plugged and four holes open. Great hole shot and 80-81mph solo, light. Very little blow out on break over. With all 8 holes plugged he has no blow out but hole shot is not as quick. He does has a hydraulic JP and lowers it all the way down for hole shot. If you want to talk to him let me know and I will PM you his phone number.
    2021 Bullet SDC
    Mercury 300R

  4. Member TheRubberDuck's Avatar
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    #4
    Thank y’all for the info. I was thinking about lowering the motor about an inch and see what happens.

    I will definitely take y’all up on the contacts if I can’t get it right. Thank you so much.
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  5. Member badmerc's Avatar
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    #5
    get a 28 bravo with the full flare, have mark add 8 pvs, and hang on

  6. Member
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    #6
    If you don't already have a foil on your cavitation plate I'd get one. The difference it made on my boat was dramatic. Before it I had to feather it for a while to get it to break over. 2 guys, tournament load and a full livewell and it took forever. Now it isn't so bad. It still doesn't like a full tank and a full livewell but it isn't bad.

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    #7
    I'd start with a foil. I ran mine about 1 to 1-1/4 below. I don't think that difference in motor height will help your holeshot though.
    SUSHII
    21XRS/SHO

  8. Member TheRubberDuck's Avatar
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    #8
    Where would I find this Foil yall are talking about. I'm certain I could find one, but if you have a specific one, I'm all ears. And thank yall again for the input.
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  9. Member
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    #9
    There is a guy on facebook by the name of Brent Comeaux he sells them. He is in south La.
    SUSHII
    21XRS/SHO

  10. Member TheRubberDuck's Avatar
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    #10
    Well, I have a foil coming from Brent. He also reminded me of something I read here a long time ago. I filled the jack plate with beach balls. That alone keeps the water from washing over when coming off plane.

    The balls and the motor one inch lower seemed to help a lot. But I’m still on the 26p Bravo. I need to put my 28p Bravo back on before the foil to see the difference.
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  11. Kllr bee
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    #11
    Put a foil on the jackplate also. It helps a lot.
    Richard aka Kllr Bee

  12. Member TheRubberDuck's Avatar
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    #12
    Quote Originally Posted by kllr bee View Post
    Put a foil on the jackplate also. It helps a lot.
    Richard aka Kllr Bee
    Richard, there is a plate/foil on the bottom. My transducer is on it. Still waiting on the foil for now. But lakes are so crazy and really too hot to get out anyway LOL.
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  13. Member
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    #13
    I had the same issue, the foil will take care of it. I couldn't believe the difference. I wouldn't raise the engine thinking it will kill your top end.

  14. Member TheRubberDuck's Avatar
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    #14
    Beach balls.jpegFoil 1.jpegFoil 2.jpeg

    So here's an update. After lowering the motor and filling the jack plate with beach balls, it would holeshot better once I put my 28 Bravo back on. BUT, I lost a lot of speed.

    Now, I got the foil on from Brent and I moved the jack plate back up so I'm 3/4" below the pad. (This is where it originally was when I bought it.) And I put 4 more small beach balls in the jack plate. I have not run it yet, I ran out of time and will be back on shift till Wedneday.

    And YES, I flipped the foil bolts so the smooth head was on the underside..... Hate how it looks, but it has a purpose. LOL

    I realize making too many changes at once usually doesn't help. BUT, I also spent my last night off re-balancing the boat. Anything with any weight is at the back of the boat. All that's in the front is my rods, tackle, seat for wife, life jackets, and net. So my next outing will either go really good, or really bad. Fingers crossed. LOL
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  15. Member TheRubberDuck's Avatar
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    #15
    Well I’m happy to report, the foil is AMAZING! Now it holeshots like it should! No feathering the throttle, it just keeps pulling up out of the water! So happy about that!

    However LOL, now when coming off plane, the washover literally covers the motor. I don’t know if that’s the foil or because I put all the weight in the back of the boat…. More to come.
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  16. Member
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    #16
    That’s awesome. Glad you got it figured out!
    2021 Bullet SDC
    Mercury 300R

  17. Member
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    #17
    You have to give it a little gas just as the boat is setting down to get out of the way of the wave that is coming.
    ‘17 Bullet 21 SDC ‘20 Merc 300R 1.60 SM 1E081012

  18. Member
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    #18
    Why do the bolt heads have to be on the underside? Never heard that before.

  19. Member TheRubberDuck's Avatar
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    #19
    Quote Originally Posted by rocketmanjp View Post
    You have to give it a little gas just as the boat is setting down to get out of the way of the wave that is coming.
    I was definately doing that, but I mean it's a heck of a wave and I couldn't get away from it.

    I've got a few things I want to try, but I may end up putting all my heavier items back where they were. I'll update once I figure this out.
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

  20. Member TheRubberDuck's Avatar
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    #20
    Quote Originally Posted by gehol View Post
    Why do the bolt heads have to be on the underside? Never heard that before.
    They are smooth rounded Allen bolt heads as opposed to the nut and bolt threads. Brent himself said it probably doesn't matter, but it's preference. Basically it makes a smoother surface for the water to move over (under the foil).
    Cody
    2018 Bullet 21SDC 250 ProXS
    2B526206

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