Motor mount position on transform

[dan1979]

Hello,

I own a 1986 Vhull power boat (same model as attached image), I have a 86 Force 50HP outboard for an engine. I recently put the motor on the boat and had to build a piece to raise the motor up about 2.5 inches in order to line up correctly with the bottom of the hull.

The boat is rated for a max of 135HP so Im guessing the original motor was a 100-115 Merc (or evn) which is much larger than my 50hp. What seems strange is the I had to build a plate to allow the motor to sit an additional 2.5 inches above the top of the transform in order to get the motor position correct and be able to clamp/bolt to the transform..

Just to clarify, the 'flair' that comes out above the prop is supposed to be within a 1 inch (from top or bottom) of the bottom of the hull correct?

Also, my motor is a manual tilt/trim (oh boy!) and there are 4 holes for the pin the be placed to change the operating position. Is it best to run the motor position closest to the transform, or in the hole furtherest away from the transform?

Thanks,

Dan

 

[roscoe]

Re: Motor mount position on transform

The bigger motor did not rest on the top of the transom. Neither did it "clamp" onto the transom.

It was raised to the proper height, then bolted thru the transom.

Since you are severely underpowered, I would think the best performance would be with the motor closest to the transom.

 

[john from md]

Re: Motor mount position on transform

I assume by the flair you are talking about the cavitation plate. This needs to be on the same level as possible to the bottom of your boat.

You are underpowered so expect to use alot of gas. If you have a speedometer and tachometer, you can try different tilt holes until you find the best for you. It may well be that the number one hole is the best but depending how you are loaded, the number two hole may prove better.

Good luck,

John

 

[dan1979]

Re: Motor mount position on transform

Hey thanks, I agree I am underpowered.. I am taking the boat out tomorrow to see what sort of speed I can get with doing some adjustments on the water.

Hopefully I can get 20mph out of it, then I'll be happy. If not, looks like I will need a bigger motor.

Thanks,

Dan

 

[john from md]

Re: Motor mount position on transform

Good luck, let us know how it turns out.

John