New Engine = Chine Walk

[blazerblobs]

I recently upgraded my 235 evinrude to a 225 v-max, and ever since I get insane chine walk at about 55mph I thought it might be the steering so I upgraded it to hydraulic steering, there is no play whatsoever, so it is not that, and the hull looks great underneath, plus it didn't do it with the old engine at speeds up to 70 never had any at all, so I don't think it is the hull. Is it possible my motor is mounted to low. Also it has a bob's low water pickup installed on the lower unit. could that have any thing to do with it?
Please help I've been wrestling with it all summer and I'm wracking my brain.
Thanks,
Jim

[blazerblobs]

P.S.
I forgot to mention it is on a 18'6" checkmate 1980.

Also would trim tabs help or stabilizers whatever you want to call them?

[jonp]

Hey BlazerBob,

This probably has something to do with a few things, engine height, weight, and prop. Do you know if the engine is at the same height as your Evenrude? If you are on jack plate you should experiment. How about the prop, what did you use before? I do not think a low water pickup would cause this. Up until this year I had a Hydrostream 20 ft w/ a merc 175 mounted on a CMC jack plate, About 3 inched above the transom. I Ran a 23-inch Laser, and on the nice dry day she would run 5800 RPM (mid 60's) trimmed out. It was a tad squirrelly but no dancing... Ran best in 4 to 6 inch light chop. Forget any tight turns at that speed, as a matter of fact, you really don’t to make any turns at that speed….J If engine height and prop type is the same. Could be a weight thing.

Good luck

Jon

[blazerblobs]

I had it mounted about the same height, I thought it was maybe to high, so I dropped it down a little, changed nothing. I guess I will try it up all the way is just about the only thing left to try.

I never thought about the weight thing, the motor is probably heavier it's definetly larger in size. If that is the case, what can be done. Any ideas?
Thanks,
Jim

[jonp]

First i would check the weight difference between the 2 engines. If significant like 50lb or more try a sand bag or something like it as far up in the bow as possible. Then see what happens. One other thing, are the trim angles the same. Other words, can you trim out the Yam much more than the Evenrude? I guessing that the 235 was a late 70 early 80s model. May not have been able to trim to the same angles, just a guess.

Jon

[blazerblobs]

The evinrude was an 85 and the vmax is a 2000. Ya, I will have to check the trim, and probably try the sandbag idea.
Do trim tabs help in this type of situation?
Thanks,
Jim

[jb123]

trim tabs will definately help, however ANY drag will slow you down...and i doubt you built that boat to slow down.i would try some bow weight,unless you learn he trick of countering the chime.

[jonp]

I Agree with JB, Trim tabs may not be the best option because it may add drag. You may be able to find small stationary ones which may add not add much drag. Drilling holes in the transon (which may not be needed) is not my favorite thing to do... I would try the sand bags to see what happens. Also watch the trim angle. I would bet the Yamaha is giving you more positive trim. Between added wieght and more trim, this could defintly be the isssue causing you boat china-walk.