What Prop pitch??

[B-Rad]

I have a 16 foot fibergalss runabout boat with a 1984 60hp johnson motor the boat weights probably 600 pounds with 2 people in it and all gear.
i have a 11X13 on now that came with the motor from a pontoon boat. the bost gets out of the hole QUICK and pulls hard but I dont get much speed out of it probably 25-30 mph tops.
so I need a better prop any suggestions?

 

[Silvertip]

Re: What Prop pitch??

Once again, just knowing what type of boat you have, what engine you have, and what prop you have is good informationi but it's relatively useless information unless you provide us with wide open throttle rpm. In your case, the engine probably over revs easily since the prop was for pontoon service. Without baseline RPM we can only guess at what you need. So I'm guessing at least a 12-1/4 x 15P or even a 17P is a starting point. Run at wide open throttle with an average load and record maximum rpm. If less than 5500 rpm drop back on pitch. If over 5500 rpm go up in pitch.

 

[GeneH]

Re: What Prop pitch??

Hi, Your guess on your weight has to be way off. I have a 16 foot aluminum runabout which weighs 680 without engine fuel, accessories and people. I would guess your setup could weigh 1500 loaded. An accurate tach is needed to tell what the engine is really doing. I am using a 19" on my setup with a '90 60 HP Johnson and getting 5700 RPM which is probably about right for me. I would be surprised if your engine will turn a 19" due to the weight of your rig but if you could get a tach and borrow a 17'" for a try that would tell you a lot. You want the engine running at it's rated rpm with wide open throttle and normal load verified by an accurate tach. Junk tacks are worthless for usable information. I think you will end up with a 15" or 17" prop. Good luck!