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

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.

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.

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.

get a 28 bravo with the full flare, have mark add 8 pvs, and hang on

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.

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.

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.

There is a guy on facebook by the name of Brent Comeaux he sells them. He is in south La.

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.

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

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Originally Posted by kllr bee

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

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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.

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.

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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

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.

That’s awesome. Glad you got it figured out!

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.

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

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Originally Posted by rocketmanjp

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.

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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.

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Originally Posted by gehol

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

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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).

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Originally Posted by TheRubberDuck

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).

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The water is so turbulent under that foil during take off I doubt there is a bit of difference. I run mine (300R) on top, it sure looks better, even though they are much harder to get in due to the hollow anti ventilation plate on the sporty. In fact I had to drop my lower unit down to get the two bolts most forward to go in. JMO. Thanks for the reply.

Edit: Adding some information for clarification and accuracy. First of all there is no cavitation or anti cavitation plate on an outboard motor. Cavitation occurs when the pressure on the low pressure side(front side) gets low enough to cause the water to boil. This will cause blade slip and pitting of the metal on the blade surface. This would be an exceedingly rare event.
What you do have is an anti ventilation plate. Ventilation occurs when the prop is pulling air from the surface (and or exhaust) causing the prop to slip. The anti ventilation plate "shades" or blocks some of the surface air lessoning ventilation. When you add the foil, even though you are getting a little lift from the angle of the foil, the main thing you are doing is increasing the effectiveness of the anti ventilation plate. The higher you run the motor the more likely excess ventilation will occur. Those of us that run the sportmaster with P to P above the pad, some approaching 2 inches above, have a hard time taming ventilation. In my particular set up (XRS and 300R) I had to lower my motor from 1-7/8" above to 1-1/2" above. I was getting tired of slinging blades and struggling with ventilation a little. Mark Croxton strongly suggested I lower the motor and give up a few MPH to help prevent ear slinging.

To the OP: If there comes a time you tire of seeing those multi colored balls in your jackplate, I have an alternative method. You will need a top plate also for my method. Go to Lowe's or similar and buy a pack of 1"x12"x48" styrofoam boards. You can cut this up into appropriate size pieces and fit them into the jackplate. You will have to cut foam into pieces you can fit under and around the rods and nuts but, with a little effort you can stack it one layer at a time to completely fill the jackplate. Add the top plate and you have a neat installation that is out of sight and you get rid of the clown look of the balls, no offense intended. Feel free to PM if you need more information on the styrofoam installation.

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Originally Posted by gehol

Add the top plate and you have a neat installation that is out of sight and you get rid of the clown look of the balls, no offense intended. Feel free to PM if you need more information on the styrofoam installation.

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Believe me, I've been on Brent about a top plate with the Bullet logo. Not only does it not look clown-ish LOL but the balls won't slip out.

I also thought about cutting a bunch of pool noodles and stacking them in the jack plate. But I wasn't sure it would give the lift the balls do.

I love my top and bottom plates

I really like using a large exercise/yoga ball in the same color as your jackplate to fill the area. It conforms to the shape and size of the volume and it's almost impossible to see. Of course you have to have the top and bottom plates for this to work.

just try to make sure you cover up all the sharp edges to keep from puncturing the ball, like I did, but they do work fairly well

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Originally Posted by Bullet 250

just try to make sure you cover up all the sharp edges to keep from puncturing the ball, like I did, but they do work fairly well

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Yes, watch those edges. :thumb up2:

I put heat shrink on all the bolt threads and sharp edges. But they are cheap balls so if one fails, no big deal.

This my results w/a 21XD. 12" Rapid Jack w/top and bottom plates. Filled the plate
w/blue sheet foam from Lowes. The foils was from Beman( out of business).
The prop was a 26 TXP. Holeshot was exceptional. The boat just literally pushed
forward w/very little bow rise. Shut down was just as good. I could chop the throttle
and the boat would rise and move away from the wave. I was running 3/4" below the pad
w/a250 XB. Top end 83.5 w/ 1/2 tank and light tackle load. This was near to perfect setup
as one could ask for. LDS

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No more clown balls!! LOL

Looks sharp, now tell me about that truck.

Attachment 534571
My pulling truck
95 F350 (yes 7.3 powerstroke)

what would you like
to know about it?

Just wanted to see a better pic of it I love those body styles. I built my son a 93 flairside 4x4 150.