how fast

[leafs]

i have a 1974 fiberglass trihull open front with i 1976 70hp johnston on it,i'm not sure what it weighs for sure but boat, motor and trailor weighs 1960lbs. when i put the trottle all the way down at the very in it slows down a little if i back it off a little the speed picks up.last weekend a friend with a gps came with me and he clocked the boat going at 30mph with 3 adults and some other gear in it. does this seem a good speed for this boat or does it not go faster because of the way the trottle works

 

[ob]

Re: how fast

leafs,Not knowing the specific lenghth of the tri-hull involved and assuming that yours is 15ft + in lenghth ,I would say 30mph is acceptable.What you need to verify is what rpm the "engine" is running at WOT.This will insure that the boat and engine is propped correctly.If you experience a lull in rpms when throttle is buried wide open ,it could be that the throttle stop is backed off too far.This will cause rpm lull at wide open due to overshooting throttle position and timing.