need help

[7816mike]

i have a 1979 hydrostream viking with a 1979 175 merc. the old owner told me that he had the boat at 83mph with a 30p prop. the boat has a 24p prop on it now. is that a line of b.s. or can that speed be set with my set up? the boat has a hydraulic jacker with @2 inch set back but it pulls the motor way up. other than that i do know the power head was just rebuilt with some (i dont know what) performance parts. can my boat do 80mph?

[gregpro50]

A '79 175 will only put out about 150hp to the prop. Those were the crank rated motors.

I don't think that motor could push that boat that fast.

[Water_Dog]

In theory, a 30p prop should be able to do 83 MPH without over revving the engine. That said, :iagree: a stock 175 (crank rated) most likely couldn't turn such a big wheel to the kind of rpm it would take. I would also guess that the quoted 83 is a speedo speed and could be substantially higher than actually speed.

[phil blomquist]

wow, I just blew up a77 merc 175 on my valero yt it ran strong with a 24 chopper but could only get 65 mph gps best day somebody is blowing smoke:D