200 HPDI Yamaha on 20' w/ bracket ?

[fdcityronco]

I'll try to make this a short story. I am a brand new 1970 20' SeaCraft owner. I love the boat, The boat was redone aprrox three years before I bought it. It came with a bracket and a 1989 Johnson 150 GT. After buying I took the motor off and found a great deal on an Yamaha HPDI 200 with 25" shaft. I mounted the motor my self and found out after the fact that obviuosly the motor was way to low in the water. So I put a bobsmachine manual jackplate and raised the motor. Took it out for its maiden voyage and it ran great, 51 mph @ 5400 rpm. Now the questions, first the there isn't enough trim to keep the bow from jumping unless I'm going a pretty good speed, what to do? Second, At a stand still the bottom of the bracket is approx 2 to 2.5 inches above the water line, as you start to go, a little bit of water comes over the edges of the platform, when on plane bracket is out of water again, Do I need more flotation and if so what's the best way? or just any suggestions. Thanks Rick

[kwluis]

Do you have trim tabs?

How much weight do you have forward? batteries, oil tank, etc...

[warthog5]

What Luis said and how big is the tub/body on the bracket.

Sound's like you have a small one? I would alway's opt for a large one to add flotation to offset the weight of the motor.

[fdcityronco]

As far as weight the fuel tank has approx 1/4 tank, oil tank is in the rear, other than the center console the only weight up front is what ever the boat it self weighs. No I do not have Trim tabs, the weight distribution from port to starboard is really good even when the weight is unbalanced the boat doens't favor one side or the other. After doing a little online research it's seems I might need a wedge to fix the bow hop but I might be able to fix it with adjustments in the jack plate, I haven't checked. As far as the flotation on the bracket I don't have exact measurments with me but it is about the same size as all the other single motor mount brackets I've seen. One idea I had but I don't know that it will work is to have two aluminum boxes fabricated and put one on either side of the the main flotation. Only problem is I can bolt it and seal it or have it welded like it was always there, but then I would have to take the whole bracket off and remount it. Something I would really like to avoid if at all possible.

[warthog5]

Do yourself a favor and put a set of Bennett Tab's on the boat. That will help the boat nose over and make the boat ride like a totally diffrent boat.

Ask anyone here that ran their boat without them and then installed them. I'd suggest a set of M-120's.

Tab's have other purpose's beside's a lean to one side or the other.

[fdcityronco]

Thanks for the info! Rick

[Bigshrimpin]

In addition to a big set of trim tabs, transom wedges and a low rake prop will help keep the bow down.

[eggsuckindog]

3 items may also help, raiseing the motor on mine helped and this was mentioned earlier. If your batteries are in the stern move them under the console and the wedges will give you enough trim to keep the bow down.