cavitation problem

[buddhaboy]

took my viper out today for the first time after the new motor. 150 johnson. at 65 it starts to cavitate bad . any advice?

[ccrick]

What kinda set up ya got?

[buddhaboy]

i have a new johnson 150 with 5 inch jack plate everythings standard and original except a 12 gallon fuel cell located in the front and a 3 gallon oil pick up tank mounted in the stern of the boat.There is also a sound system. this makes me carry 2 batt. for comfort also mounted in the front running on a switch.

[ccrick]

how high is the engine jacked and what prop?

[buddhaboy]

its a turbo prop 14 1/4 25 pitch stainless steel, and my motor is at its highest setting on the jack plate.

[buddhaboy]

heres some pics

[77viper]

You need a shorter midsection. You have a 25" and need a 20".

[Hippie459MN]

That motor is way to low. Get the prop shaft even with the pad. I bet you really bring that boat to life then and get a lot more speed out of it. That looks like a 25 inch motor to me but I could be wrong. A 20 inch would be ideal. Can you raise your jackplate anymore to Get the motor up more? Also, is it just me or is your jackplate on upside down?

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[buddhaboy]

yes its a 25 , but its all i have for now. the jack plate i had a friend make for me . i can drill some more holes and move the motor up about three inches , if you think this would help. at 65 its got alot more , but the cavitation at that speed is scary! i was thinking maybe it had to go down? good thing there is a great site like this one to help first time hydrostream owners like myself get the help we need and make a boats perform to there fullest.

[buddhaboy]

Do you think moving the motor up a couple inches and adding a hydrofoil would help ?

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