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 Outboard swap speeds 
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Post Outboard swap speeds
Finally got my outboard swapped out. Have a 2 stroke yamaha 70 tiller. Currently the motor is mounted with the cavitation plate about .75" above bottom of hull. Is currently has a 18p 3 blade. Had about 10 gallons of gas up front, and when I hammer it, jumps out water like a hydrostream. It hits 40 quick, but can't trim, bounces to much. Will prob have to move battery up front under deck to add weight up front. I also noticed that my trim tabs on my hull were bent down slightly to keep my kawasaki from porpoising.

What kind of speeds are you guys getting with outboards on these hulls? And if someone has a yamaha 70 2 stroke, what pitch prop you running?

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Sun Dec 10, 2017 8:02 pm
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Post Re: Outboard swap speeds
if u getting 40 out of that 70, u need to just be happy and run it.


Wed Dec 13, 2017 7:48 pm
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Post Re: Outboard swap speeds
Its going to cost a jackplate and a good prop to gain speed. See if that cost is worth it.

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Thu Dec 14, 2017 7:50 am
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Post Re: Outboard swap speeds
My outboard bounces also above 50 mph. With 9 adults and 3 kids it will only get to 47 mph problem solved! :lol:

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Thu Dec 14, 2017 8:23 am
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Post Re: Outboard swap speeds
It could very well be my trim tab that I tweeked to work with the PD. I just haven't had the time to hammer it straight and see if it helped. From 3/4 to WFO is really no change in speed due to I can't trim.

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Fri Dec 15, 2017 10:11 am
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Post Re: Outboard swap speeds
banded-mallard wrote:
Finally got my outboard swapped out. Have a 2 stroke yamaha 70 tiller. Currently the motor is mounted with the cavitation plate about .75" above bottom of hull. Is currently has a 18p 3 blade. Had about 10 gallons of gas up front, and when I hammer it, jumps out water like a hydrostream. It hits 40 quick, but can't trim, bounces to much. Will prob have to move battery up front under deck to add weight up front. I also noticed that my trim tabs on my hull were bent down slightly to keep my kawasaki from porpoising.

What kind of speeds are you guys getting with outboards on these hulls? And if someone has a yamaha 70 2 stroke, what pitch prop you running?


I was running a 40hp Mercury on a 1648 riveted MV hull and ended up filling the live well up in the mid seat to keep the bow down and bounce out of it. Tried running props with less rake and it helped in the end.


Fri Dec 15, 2017 11:01 am
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