proper mounting of older motor on inflatable.

[courson515]

I have a 16' zodiac style inflatable with inflatable keel. It has a 1982 40hp evinrude on it. I am wondering how it should be mounted. Right now the cavitation plate is about 1.5" below the bottom of the boat. I have read that it should be even with or 1-2 inches above the bottom. But I also read that older motors were supposed to be like that. Someone please enlighten me. Right now I can go about 14mph and I know it should he faster. But when I throttle it into high I can hear it Rev faster but don't really see much more speed and then it tends to over-rev and lose all thrust. Was possibly thinking of getting a hydrofoil and maybe a jacking plate. Any help would be greatly appreciated. I'm new to this stuff. Thanks in advance.

 

[Sea Rider]

Welcome to Iboats,

All you wanted to know in a condensed version....

http://www.rib.net/forum/f50/abc-sib...nes-58373.html

If any of the points not clear, simply ask..

If engine is that old as inflatable, you could have already a kaputt prop with spun hub condition.

Happy Boating

 

[courson515]

Thanks Sea Rider. That helped me understand a lot more. I will try those different things out and see what happens. Looks like it might be a lot of trial and error. I'm gonna be upgrading the motor to a new e-tec this winter but wanted to see what this motor will do first too.

 

[Sea Rider]

Proper engine/transom height & proper pressure on all tubes and keel acccounts for most of an inflatable best performance, trim and deck balance should be taken into consideration too, Engine and prop must be in opt working cond to work nicely along those 4 parameters.

Happy Boating