Help !! Mercury enginge set up

[melaniew9]

I have a sanger alley cat tunnel boat with a new Mercury 250 Pro XS motor with 1.62 Sports Master gear case. I have a new HUB kit in the Ron Hill Prop with 19inch spline.

When motor is jacked high in water, the engine is going only 10 miles a hour at 4000 RPM. Cavitation of plate is 4 inches from bottom of boat

What is the problem?
Is the HUB kit slipping?

PLEASE NOTE ADDTL INFO:
prop shaft is even with center pad of boat? Is this alright????

prop shaft is 2 inches above the outer sponsons of boat

inner tunnel pad is 5inches above bottom of boat.
cavitation plate is 7 inches above outer sponsons of tunnel boat.



Please call me at 718-607-8938
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[noots]

Motor is way too high. Prop shaft should be even with outer sponsons or below. Try a couple inches below and mess with it from there. With your current setup the prop is barely in the water!

[gm250]

[QUOTE=noots;2370043]Motor is way too high. Prop shaft should be even with outer sponsons or below. Try a couple inches below and mess with it from there. With your current setup the prop is barely in the water![/QUOTE he sent me pics becouse this is my old boat the prop shaft is even .jack has to run a smaller wheel for break in.he was not giving it time or more rpm to come over cleaver 15/28.need to buy break in prop i ran 1 1/2 above bottom