Re: SU 310-Planes well but bow too high at low speed
Nightstalker,
Your boat is acting normally. Most small boats will initially "plow", bow high, at partial throttle as you described. The suggestions for weight redistribution are good ones.
You'll need to experiment to find the throttle setting that will be less than maximum, while still keeping the boat on plane. You'll probably find you have to use wide open throttle for the first several seconds. That will help the boat quickly get "over the hump" and flatten out in full planing mode. Then, reduce throttle a bit at a time to find the setting that lets you cruise comfortably while still on plane. If you reduce throttle too much, the boat falls off plane, the bow points skyward, and you have to start all over. Part of the fun of learning your boats characteristics.
note: the bow high attitude is when the engine is likely getting the poorest fuel usage per mile. It pays to get on plane, then throttle back a bit to approx. 3/4 throttle.
Larry