Posted by bobhil on 05/03/07 - 5:11 PM
#1
I have a 17 Montauk with a Honda 90, even in flat water it begins to begin porpoising motor trim does not have much effect, what can I do to stop this.
Edited by Tom W Clark on 05/05/07 - 8:27 AM
Posted by Joe Kriz on 05/03/07 - 5:35 PM
#2
bob,
2 things come to mind right off the top.
1. What height is your engine set at?
It might be too low.
2. You might need to try a different prop.
I would start off by looking at the height of your engine.
The anti-cavitation plate should be about an inch above the keel of the boat.
If so, raise your engine up one set of holes or whatever it takes.
Once you get the correct height of your engine and it still wants to porpoise, then the next step would be to look at different types of props...
Posted by RGT on 05/04/07 - 5:51 AM
#3
Too much weight aft could be the problem.
The solution for my 160 Dauntless, which are propoise prone, was a SE Sport 300 hydro-foil.
Posted by Tom W Clark on 05/05/07 - 8:31 AM
#4
Agreed. Porpoising is usually the result to a center of gravity too far aft. The problem can be exacerbated by an outboard motor set too low on the transom and a prop with poor grip.
The Honda 90 is a very heavy motor. If the battery(s) is in the stern this may contribute to the problem as could a large fuel tank, extra accessories and gear, etc. A hull that is somewhat waterlogged can put a lot of weight aft as well.