17' Bayliner Trophy w/85 force

I recently purchased an 1985 bayliner trophy with 85 force. boat runs excellent and has 140 psi in all cylinders.......i have a question about performance and props. The boat came with a spare prop that is 21 degrees pitch. the prop on the boat has no markings. the boat gets on plane fast and seems comfortable at about 25mph at a little over half throttle. When i open her up the motor makes more noisy and rpm but the speed only increases to about 30 mph. My question is would the 21 pitch give me more top end? I'm
not concerned with hole shot because i just fish and don't ski or pull anything. Seems to me maybe the prop on the boat is more for hole shot and not top end....is 21 degrees better for top end....thanks in advance.............JD

Re: 17' Bayliner Trophy w/85 force

I think I have the same boat, an '85 Bayliner 16' bowrider. It came with an 85 horse Force, now I run a 115 Evinrude. I run a 15 pitch that has been rebuild to 16 pitch specs at 5000' elevation; tope end at about 33 mph. The lower the pitch gives you hole shot, higher pitch top end. General rule of thumb is to run the prop that allows the boat to run at top operating RPM at Wide Open Throttle.

Re: 17' Bayliner Trophy w/85 force

A 21 pitch prop is too much pitch for that boat. You should be using a 19 for cruising and a 17 for pulling skiers etc. This should give you 5000 to 5500 RPM.

Regards,

John

Re: 17' Bayliner Trophy w/85 force

Put two people in your boat a 3/4 tank of fuel and a cooler of food and drinks.
Put on the 21p and go for a ride.The tach should read 5400 RPM at WOT.
21p and you get 5000rpm then you need to go to a 19p to raise the rpm.. Lower then you go to a 17p.
You should worry about the optimum performance with the right prop.Say your boat needs a 19P and you run a 21 then you get poor economy.Maybe a little more speed but that can damage your motor by not letting it run at the right timing.
A 17 will give better fuel economy but allow the motor to over rev.Then poor performance.
Get the right prop and let the guys who designed the motor worry about variables. J