I think my motor may be to low?

[dmoriarty51]

So, I'm thinking my motor might be mounted a little low. I get this great little fountain of water shooting straight up at the motor, some lands in the boat of course, and once I trim up enough to stop it the thing porpoises and i trim it back down enough to stop that yet keep this water fountain out of the boat.

Cavitation plate is basically even with the keel, looking at other boats with similar hulls they all seem higher. I have had someone look over the back while on plane and the cavitation plate is indeed submerged and it appeared to them that water was running at the next plate up. Not sure how accurate that test was since moving a grown adult to the extreme rear of a 16 ft boat on plane does change its attitude.

Near as I can tell this motor has been with the boat from day one, and is mounted as low as the transom will allow. Of course that doesnt mean its setup right. Lets see what you guys think

 

[metriccrescentwrench]

Re: I think my motor may be to low?

OOPS, double post. I got ahead of our slow internet at work.

 

[metriccrescentwrench]

Re: I think my motor may be to low?

I have had someone look over the back while on plane and the cavitation plate is indeed submerged and it appeared to them that water was running at the next plate up.

Right there's your answer - it's too low. Try raising it one hole at a time, my guess is that you can go up a couple of holes (but I'd still try one at a time). With each change make sure you have good cooling water flow through the engine.

Not sure how accurate that test was since moving a grown adult to the extreme rear of a 16 ft boat on plane does change its attitude.

Can you have a second grown adult move to the front to balance things out? Or else move some weight to the front while you do your tests. (I don't think this changes the fact that your engine is low).

 

[BonairII]

Re: I think my motor may be to low?

At WOT the anti-ventilation(cavitation) plate should be running just on the surface of the water.

 

[Woodonglass]

Re: I think my motor may be to low?

This might help...

 

[sublauxation]

Re: I think my motor may be to low?

I'd agree it's a bit low but to me it looks about even with the bottom now, maybe just a bit lower. I'm no expert but many here would say take the fin off and run it that way first.

 

[dmoriarty51]

Re: I think my motor may be to low?

foil or no foil this issue still exists.... think i will try raising it up a hole or 2 and see what happens, i do have a water pressure guage so i can keep an eye on cooling flow

 

[dmoriarty51]

Re: I think my motor may be to low?

no new pics, but i raised the motor 2 holes to get the antivent plate event with the hull.. and the water fountain is gone and it seems more responsive, cooling is still good. i doubt i will go more but i think i could go to the last hole easily beyond that is going to require a drill and i dont need it that bad