I have the BUCK!

[Robsauto2]

So after some changes I made last weekend I now have the "buck" problem. Here is what I changed:

1. Trued the hull using a 16" hand board sander, 80 grit.

2. Installed a used stock pump shoe after destroying my old one trying to remove it.

3. Sanded the intake grate flat with the shoe.

4. Installed the FF modded plate at about .990"

My speeds were about the same as 2 weeks ago before any of these mods, 76 mph, but now it bucks. So I started swapping parts back to my old setup to see what caused it. I installed my old modded plate and it bucked worse, could not keep it in the water at over 74 mph. Then I removed my modded 800 grate installed a bone stock 800 grate. It got better. Installed the FF plate, speed was 76 and much less buck, but it is still there. So the Jim's FF plate is a keeper. Installed 1 shim under the rear plate pads, no buck at all but lost 1 full mph. So What is different that caused it? My old shoe had .035 removed from the mounting surface allowing it to ride higher in the hull. I am going to try and fix my old modded shoe and see if the buck goes away and still runs 76+ mph. So my question: Is there anybody who has fixed this problem for sure? After much searching I saw where many of you have shimmed the tabs down, but I think Spud did that and he still has the buck. Then after all that I sucked a rock and had to perform pump surgery 20 miles from my truck...see pic. And then fried my 3rd advent in the middle of the river. Luckily I keep the stocker on board, changed it while floating down the river. Oh well, live and learn as they say.

[IowanGPR]

this is on your 1200?? what kind of mods are you running. I am at 7400 rpms having trouble finding speed. usually average just under 71. I did have my setup to 74.8... next time out it didn't run nearly as fast and I hadn't done anything to it. I think I need a new prop from IR but he won't respond to my PMs good numbers and good LUCK with tha BUCK.


Ben

[Insanediego Joe]

PM hydrotoys, he may have an answer for you Rob.

[Chrisrokc]

this is on your 1200?? what kind of mods are you running. I am at 7400 rpms having trouble finding speed. usually average just under 71. I did have my setup to 74.8... next time out it didn't run nearly as fast and I hadn't done anything to it. I think I need a new prop from IR but he won't respond to my PMs good numbers and good LUCK with tha BUCK.


Ben

That 7400 rpms is your problem. I think you want to be closer to 7150.

[Chrisrokc]

Oh and the buck problem...


I haven't had this happen to me yet but I am positive it will happen by years end. I plan to try the hole drilling method to stop it. Put two holes in the shoe to releave pressure and stop buck.

[YudLuz2]

Oh and the buck problem...


I haven't had this happen to me yet but I am positive it will happen by years end. I plan to try the hole drilling method to stop it. Put two holes in the shoe to releave pressure and stop buck.

No need to drill holes on your pump shoe unless you are running close to 90 or above. And there is a better way to relieve the pressure than this setup. His buck started because of one thing for sure. Pump shoe
placement. He probably let it slip foward, needs to be all the way back
against the rear. Second is the height that the shoe is up in the hull.
Ben

[Chrisrokc]

No need to drill holes on your pump shoe unless you are running close to 90 or above. And there is a better way to relieve the pressure than this setup. His buck started because of one thing for sure. Pump shoe
placement. He probably let it slip foward, needs to be all the way back
against the rear. Second is the height that the shoe is up in the hull.
Ben

Good info to know. I have always been told the nickle, dime thing for height in the hole, and pull the shoe all the way back when putting it in.

Would that save me from the buck? Or is it kind of the luck of the draw?

[YudLuz2]

Its all about the angle of the water being directed to the prop.
You can find tune stuff like, ride plate height, grate placement
and pump shoe placement to change the flow of the water to
the prop. Also the way the prop is pitched. And leaving the nose
cone off, can also help. It spreads the water more evenly
across the blades of the prop. Your just changing the way the water is coming in without the boat overstuffing the pump. Finding what works
best on your boat is trial and error, your speed has a lot to do with
the way your setup needs to be. Sometimes a 10 thous. shim is
all you need. Drilling holes in your shoe will cause the boat to suck down
harder to the water, than you get more drag and you start loosing speed
on the slower boats. You need to go way loose, no tabs and a lot
more angle to get your speed up. But then you get to that point
you start over stuffing again. So you need to find that edge without
going to far for your best speed. Rider weight and riding position must
also be consider when you are setting up for peak speed.

[Robsauto2]

this is on your 1200?? what kind of mods are you running. I am at 7400 rpms having trouble finding speed. usually average just under 71. I did have my setup to 74.8... next time out it didn't run nearly as fast and I hadn't done anything to it. I think I need a new prop from IR but he won't respond to my PMs good numbers and good LUCK with tha BUCK.


Ben

Ben this is a Dan Lamey ported 1300 BB with vf2's 05 pump 14/24 dynafly. I have never seen the speeds others claim with similer setups. But these numbers were in 112 degree air temp also.

[Hydrotoys]

Call me Wed sometime Rob.