I have a 21 ft Gregor aluminum boat with an 85hp Suzuki and i can only go 30mph top speed. doesn't that seem slow, like there is something wrong with the motor. The boat is rated for a 70hp and i have an extra 15hp with the 85hp. any thoughts....
when i am going down swell my motor gains about 200 rpms and going up swell it seems to slow down 200 rpms. I can cruise all day long at 3600rpms at 20mph at 3/4 throtle, but when i give it WOT it only goes 500-600 rpms more and only gets 26-30 mph. any idea on what the redline is for the motor?
What kind of load are you running and what prop?
It could even be the way it is set up on the boat or the motor is not running properly.
It should get to 5500 RPM or more, but I do not know the specs on that motor
not sure on the weight but two people(350lbs) 24 gals of gas(190-200lbs) and cc, with two home made wood seats, on a 21 foot gregor aluminum. with a prop that says 13.5x15 it is a solas rubex, i also have a prop that says 13.25x17 and this prop is alot smallar than the 13.5x15. the 13.5x15 has big fins and the 13.25x17 has smallar fins but i need to repair the smallar prop.
Hey sk, i also have the same motor on a 18' South fork aluminum boat. i am guessing the boat, motor and two passengers weigh about 1100-1300 pounds. It's a semi v boat. I run about 35-38 mph with the same prop at about 4300 rpms. i am going to drop down to the next size on the prop hoping it gives me more rpms. I had the 13.5 x 17 on there and it came out of the hole slower and ran about 500-700 rpms slower. My top speed didn't change much. Good luck!
