Yamaha 130 V4 Project Build.

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Originally Posted by Dave Strong

Don't use 5200 if bolt the motor directly to the transom.lol
25lbs less weight on the back of your boat could really screw up the balance.

Dave

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Thats my concern but if it does, putting the jackplate back on should fix it. The only issue I forsee is the slow/mid range hop might be worse. If it is, I can just move the motor back to get some more lift.

I took some measurements and bolting the motor right to the transom using the existing holes I end up 1/2" lower than it is now. I was going to drop it down a little anyway as its felt very loose at 85+. Even yesterday with a full tank and my smaller prop if starting feeling really loose back there at 85. I think between lowing it and losing the weight it might be a wash. The setback will be the same if I lose the jackplate..

If that were mine I would rework that lower bracket so the shifter goes down through the swivel as original.
For a tiller arm you could consider sandwiching an aluminum plate under the powerhead and have it protrude out the front as needed.

Time to widdle a custom clamp to solve your issues and loose another 15lbs

I dont know that losing weight back there is the answer. I would actually like the back to feel more planted and reduce the hop. My new 28 I had a lot of cup put in and the hop is almost gone. Im thinking it all over but I might even try more setback to settle the boat down at high speed.

I would think, and please feel free to comment, that increasing the distance between the prop and the back of the two sponsons (the only parts touching the water) would make the boat more stable. The boat would think its longer. But...it would also increase the crabbing effect as the prop would have more leverage as it paddle wheeled sideways. The paddle wheel effect / crabbing is my issue if anything.

I know that thing handles great but I don't care if Jesus is driving. A 13ft boat at nearly 100mph is never gonna feel planted! :D

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Originally Posted by baja200merk

I know that thing handles great but I don't care if Jesus is driving. A 13ft boat at nearly 100mph is never gonna feel planted! :D

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Ain't that the truth.lol
Maybe just best to mount it to the present plate and see how it goes, bit more set back than you wanted. But may run great and way less work than pulling the plate first and needing to put it back on. Easier to only change one thing at a time, cuz if change a couple your never sure just what didn't work out.

Dave

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Originally Posted by CharlieN

If that were mine I would rework that lower bracket so the shifter goes down through the swivel as original.
For a tiller arm you could consider sandwiching an aluminum plate under the powerhead and have it protrude out the front as needed.

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I really like the plate idea. Can a .250 thick SS plate be used
or is that to much.? Spline engagement issues.?

Dago

As long as the shaft length has not been set yet you have total freedom. My mind was on a piece of 7075 but the stainless would be tougher where the tiller bolt goes through.

Thats right. I love the plate idea.!

Dago

It gives you allot of freedom to get the clearances Chris is looking for without things getting out of hand with needing to change the steering cylinder or other components.

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Originally Posted by Mr. Demeanor

Decided to tear it apart and dry fit some parts before painting and ran into a pretty big issue.
The way the swivel was done in order to get the mid down to 15" also adds 1.5" of setback which is exactly what I dont want. Im going to have to get Marty Powell to look at it and see what he thinks. If we reduce the setback, the bracket at the bottom of the swivel will hit sooner reducing how far I can turn the wheel side to side.
Tuner is also an inch longer than the midsection.

Attachment 298694

You can see here with the bracket for the bottom motor mounts right against the mid, the top is about 1.5" out. would have to make some spacers and get longer upper motor mount bolts which isnt a big deal but I dont want the setback. It may also cause issues with my steering etc. but I can probably just make the new tiller arm longer.

Attachment 298695

The other option would be to simply remove the jack plate and see what happens. That would be another 20 pounds off the transom and my setback would be about the same in the end (my jackplate on has 1.5" of setback). The downside is if the boat doesnt like it, it would mean taking it all apart again.


As it sits, the new mid/swivel is 9 pounds lighter than the old. Lose the jackplate would be a total loss of about 25 pounds by the time I add back in a new tiller arm. Thats huge on this boat.

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i had to use trim stops and one inch transom wedges on mine to get it to tuck where it would come out of the hole and still turn all the way. if you just moved the bottom of the jack plate in as far as you can and left the top alone that shouldnt mess with the setback. you would loose the slot the bolts ride in but if you are happy with the height it is at now that shouldnt be a problem..........benji

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I would think, and please feel free to comment, that increasing the distance between the prop and the back of the two sponsons (the only parts touching the water) would make the boat more stable. The boat would think its longer. But...it would also increase the crabbing effect as the prop would have more leverage as it paddle wheeled sideways. The paddle wheel effect / crabbing is my issue if anything.

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EDITED my post, did not make sense:

Being more stable is a possibility I would think. Your points form a tripod so to speak. The farther those legs are apart they more planted it may feel.

I like that mid.
C

The prop is applying force sideways to the skeg in my case a lot of force because its so high. The further the prop is from the transom, the greater the the leverage the prop will have to crab the boat.
Ive thought about adding more skeg forward toward the front of the gearcase. Gordon actually mentioned it awhile back.

The plate idea is cool but more complicated IMO. Im about keeping it simple. Bolting on a new tiller using the top engine mount bolts or just welding on a new tiller arm is the simplest solution IMO.

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The plate idea is cool but more complicated IMO. Im about keeping it simple. Bolting on a new tiller using the top engine mount bolts or just welding on a new tiller arm is the simplest solution IMO.

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I am not sure that the plate is complicated especially if that mid has bearings that do not want undue heat from welding.
granted a bolt on tiller does not impose heat but your mounting points are narrow so the fabricated parts need to be beefy near the attachment.

The plate would just sandich under the powerhead. the bottom pan gets trimmed as needed to set in place.

One of my thoughts where the swivel point is moved forward is that this moves the prop further back increasing steering load at high speed. Granted it is not uncommon to move the swivel forwards in high performance applications.

I also wonder if a 1:1 gear ratio and short prop would work well for your needs. Much less side walking of the prop at speed.

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Originally Posted by Mr. Demeanor

The prop is applying force sideways to the skeg in my case a lot of force because its so high. The further the prop is from the transom, the greater the the leverage the prop will have to crab the boat.
Ive thought about adding more skeg forward toward the front of the gearcase. Gordon actually mentioned it awhile back.

The plate idea is cool but more complicated IMO. Im about keeping it simple. Bolting on a new tiller using the top engine mount bolts or just welding on a new tiller arm is the simplest solution IMO.

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Plate is far easier to machine and fab than a SS billet tiller. Just give me a print ill make what ever you want.
If it was about keeping it simple you would be happy with a 94mph 13' boat. That's out the window.:cool:

Dago.