RPM question.

[Wallyboss]

Will lifting (straight up ) the motor on the transom lower or raise my rpms?

[Half-hitch]

If you lift it high enough, it will greatly increase rpms for a few minutes, then decrease them to 0 indefinitely

[plncrzy]

Will lifting (straight up ) the motor on the transom lower or raise my rpms?

Raise RPM's ... less water density, easier cavitation, etc

[spinner]

-be careful, especially if you don't have a water pressure gauge as if you lift it too high and lose water pressure, you can blow your engine as there is a required water pressure needed to cool your engine properly and if you drop below it, trouble follows..........

[Wallyboss]

I am talking about just 3" higher and the anti- ventilation plate will still be level with bottom of boat. I am just trying to get some clearance so I can trim my motor all the way down when the boat is on the trailer. Now I am wondering if raising the motor if I will need a new prop different pitch.

just looking at what my options are

[Half-hitch]

Will lifting (straight up ) the motor on the transom lower or raise my rpms?

Raise RPM's ... less water density, easier cavitation, etc

Water is pretty much uncompressible - it won't change in density, and certainly not over a few inches in depth.

[mikemicropterus]

WallyBoss, it's an anti-ventilation plate, cavitation is the rapid collapse of air bubbles that cause a burning or erosion of area that the CAVITATION takes place. An airplane prop will cavitate but there's no water. Ventilation is the introducing of air into the water flow to the prop from stuff on the bottom of the prop or from outside the lower unit.

Cavitation and ventilation are commonly confused and missed used by most of the general public.

OK now if you place the ANTI-VENTILATION plate even with the bottom of the boat then you just put the motor at the right ENGINE HEIGHT for your boat, if it is flat or a slightly modidifed V bottom. Most dealerships DON"T KNOW this or just plain don't care. I do this adjustment to boats constantly. You will gain possibly 300rpm and speed and better boat handling.

ask around to people who have had this done.

Water pressure will not be a issue as you are not going up high enough. Are you running an aluminum prop?????

[Wallyboss]

Mike you have a pm.