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Shaft length

frog

New member
" Ok, heres the deal I picked

" Ok, heres the deal I picked up a 25" motor to find out that I have a 20" transom
I was going to put a 5" lift on the transom but I was wondering how much differance is there going to be if I left at 20"? "
 
" frog,

If you have


" frog,

If you have a boat that is meant to plane, it's going to make quite a bit of difference, it may not even get up on a plane. I get an extra 4 MPH just by trimming my engine up a little, and it's a 20 inch shaft on a 21 inch transom. There is a post somewhere down the line discussing the same thing, but what I reccomend is to check out a West Marine, if you have one in your area, or check out www.westmarine.com . They carry a manual jacking plate (adjustable engine mount), rated for 225 HP, with 5+ inches of lift for $90.

Jon "
 
"Frog.... Running a 25" sh

"Frog.... Running a 25" shaft engine on a 20" transom will result in quite a bit of drag. The extra 5" length will endanger the lower unit due to underwater obstacles. Another bad feature is that the extended length will, at higher speeds, create what is called a dual rooster tail, a high wall of water spraying upwards and backwards from both sides of the engine.

Joe
"
 
" ok guys thanks I didn't

" ok guys thanks I didn't think it would be a good idea. I already started the transom work. It pays in more than one way to be a auto body tech
"
 
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