Another cavitation plate question.

[cajun555]

I read all these post about the cavitation plat being even with the bottom of hull. Now is for newer motors or all? The c/p now is about 3 inches below the hull. I can raise the motor pretty easily, but my concern is on this 1956 30 hp Johnson seems it has 2 points where it picks up water for pump. 1 pick up point is on port side of motor directly above c/p. The other point is on front side of exhaust housing. Idleing in water I don't really see a problem, But once I get up on plane it seems that the port side water pick up will be just at the level of the water or above and the pump will try to pull the least resistance " air". <br />Someone correct me if I'm wrong or should I just try raising motor on a trial and errow.

 

[WillyBWright]

Re: Another cavitation plate question.

Those should run an inch or two below the hull. What you're referring to is the newer motors with water pickups on the side of the gearcase. Yours picks up just behind the prop where the exhaust comes out. I've never figured out the stuff above the plate.

 

[Chris1956]

Re: Another cavitation plate question.

Cajun555, The water pickup on top of the anti-ventilation plate is used when the motor is in reverse. I guess the manufacturer was concerned that the water supply pickup behing the prop would be starved if you drove in reverse fro a while.

 

[cajun555]

Re: Another cavitation plate question.

Maybe I'll try the c/p even with bottom of hull and have my first mate keep an eye on the water discharge at different speeds. I've got another l/u ad was looking at it with a bright light up the lower pickup area, it looks like a tube up to the side pickup then up to the pump. Thanks for the input.