Undrivable over 65

[illinicobra]

So I got this boat last fall. Set it up to my liking over the winter by adding hydraulic steering and a 6" atlas hydraulic jackplate. I posted before about my motor looking 1/4" higher on the right than the left. Several said it should be fine. Well it's a 2007 nitro 591 with a 200 optimax on it. Brand new 25 fury. Great till 65ish. Then gets scary squirrelly. Propshaft to pad all the way down which is how I was running it is 4 1/8th inches below the pad. So I came home and did some checking and found these pics.. pics are of the deck, top of transom and then top of jackplate..

[jarhead175]

Now check the level of the pad to the motor.

Boats are put together in two pieces a vast majority of the time they are not mounted truly square together.

I have seen a few mounted crooked never heard of one causing a issue not saying it isn't possible. Since you have no issues till 65 mph my guess is that your experiencing "chine walk" and need a lesson from a experienced driver to learn how to drive at those speeds. You can't drive through it you either have to learn how to stop it from happening with the correct driver input or change you setup to slow down.

[illinicobra]

It is possible to chine walk that bad with the motor that low? It's not like I was trying to run 2" below the pad..
This seems way more violent and the boat seems to start pivoting. I can believe that the top cap can be off 1/4". But that's over 80"+, not 16" across the jackplate.. There is all of 1/4" of the jackplate exposed over the top of the transom on the driver's side

[illinicobra]

Plus the guy I got it from before the jackplate said he could only get to 64 before he got scared. Also a different prop than now.. I chalked that up to the cable steering that was on it. Guess that maybe that wasn't the issue? Idk

[pmgoffjr]

Tons written on chine walk.
Raising the motor will help but getting a good driving lesson is the only real answer.

[Elmer Swan]

I Would Think There's something wrong being that much of a difference. I have a manual jack plate and I Was at my prop place and right away he noticed that the motor wasn't level he measured and it was 1/16 inch difference from side to side I got Home and leveled it and it made a big difference. Just Saying

[John Jackson]

It is possible to chine walk that bad with the motor that low? It's not like I was trying to run 2" below the pad..
This seems way more violent and the boat seems to start pivoting. I can believe that the top cap can be off 1/4". But that's over 80"+, not 16" across the jackplate.. There is all of 1/4" of the jackplate exposed over the top of the transom on the driver's side

Yes, the lower you run a prop, the worse it can chine walk.
Is the motor centered at the bolts and at the foot? It should be centered and vertical. Either off will affect driving.
2nd, did you put the level on it on land, or in the water. It should be in the water loaded,people and all, how you normally run.

[illinicobra]

Here's what it looks like...

KIMG3455_06.JPG

[John Jackson]

I've never seen one that far off. I don't know what is exactly off without seeing it in person, but it looks like someone misdrilled the starboard holes half an inch, or mislocated the template that far off. That needs to be fixed. And I would remove the jackplate and inspect the holes in the transom for damage that might be hidden. If the transom is OK, I would change the plate to transom height about 2" higher and completely redrill and remount the jackplate. And you might consider 6 bolt mounting. That far off would make almost any bassboat a bitch to drive at speed.

[pmgoffjr]

You should eliminate the variable. Find a seasoned rigger that has a laser rigging light or knows how to arc your pad. Then you’ll know if the motor is off to the pad, which is what matters. Top of the transom really doesn’t matter. I agree it looks bad but it very well could be correct. A quick and fairly easy way to at least get close is to use the two mold marks (bumps) in the center of the transom. Use a straight edge to draw a line between them and measure to each side of your plate. That’ll be close.

I have seen some awful transom angles before and you might have one, but you have to verify from the bottom not the top.

[Elmer Swan]

WOW looks almost like it's 1 hole difference between the sides and I will Second about getting an experienced rigger to at least look at it

[rgsauger]

And.......don't forget solid mounts on your motor if you're going to run 60 mph plus

[Bandone]

WOW looks almost like it's 1 hole difference between the sides and I will Second about getting an experienced rigger to at least look at it

Yep

[illinicobra]

96162425_10223331388052455_636189153091911680_n.jpg95796309_10223331388572468_1523361738102145024_n.jpg

So here's before and after. I took the jackplate off. Took it apart. Made a template to lower the right side 1/4" out of some plastic sheet I had. Had my buddy who's a certified welder at a fab shop fill the holes then re-drill to my template. It may not be perfect, but I feel it couldn't hurt and I feel I have a better chance now.. I will post after I get to drive it.

[digthemup]

It does look better in reference to the top of transom, but as Pat Goff pointed out "I have seen some awful transom angles before and you might have one, but you have to verify from the bottom not the top."
Your motor should be plum to the centerline of your hull's keel line. Did your friend find the holes to be 1/4" off after the JP was verified as squared?
BTW, 3/4" would be the distance from center to center of holes on your motor mount, and try NOT TO OVER TRIM your motor once you are on plane, which will aggravate your chine walk. Once you are on plane, start trimming up in very small tap increments until you feel the oscillations, now tap down 1 or 2, if it stopped, stay there and get some seat time.
Here is a link that may help you:
https://www.screamandfly.com/content...-How-To-Fix-It

[shafer22]

Jack plate is crooked

[illinicobra]

It does look better in reference to the top of transom, but as Pat Goff pointed out "I have seen some awful transom angles before and you might have one, but you have to verify from the bottom not the top."
Your motor should be plum to the centerline of your hull's keel line. Did your friend find the holes to be 1/4" off after the JP was verified as squared?
BTW, 3/4" would be the distance from center to center of holes on your motor mount, and try NOT TO OVER TRIM your motor once you are on plane, which will aggravate your chine walk. Once you are on plane, start trimming up in very small tap increments until you feel the oscillations, now tap down 1 or 2, if it stopped, stay there and get some seat time.
Here is a link that may help you:
https://www.screamandfly.com/content...-How-To-Fix-It

I hung 2 plumb bobs, one off the keel at the front and one off the transom center(the factory marks I found). I shot a laser through the 2 strings and found the laser hit the passenger side of the gear case. It was off somewhere between 1/4-1/2" from center. Will post more after I get the chance to drive it. With what it was doing, there's no way I made it worse

[digthemup]

I hung 2 plumb bobs, one off the keel at the front and one off the transom center(the factory marks I found). I shot a laser through the 2 strings and found the laser hit the passenger side of the gear case. It was off somewhere between 1/4-1/2" from center. Will post more after I get the chance to drive it. With what it was doing, there's no way I made it worse

icobra,
Sounds like you took quantifiable steps to assure the work needed to be done, and I am sure you check the actual JP for square prior to redrilling it. I bought a Vance JP few years back that was about as square as a 3 legged dog, and had to loosen every bolt on it to resquare it, though afterwards had to replace with a better quality Slidemaster.
I hope you read the link, which will help you understanding chine walk.
Be well and be safe

[mdtritn21]

Did you verify that it was not the holes in the transom that were drilled wrong or enlarged by the blots being lose allowing the jack plate to move?

[illinicobra]

Did you verify that it was not the holes in the transom that were drilled wrong or enlarged by the blots being lose allowing the jack plate to move?

The holes in the transom were off. Not enlarged. Just crooked. I had the jackplate modified to correct the issue.