CONTINUOUSWAVE

I have a 1994 Outrage 24 with twin Mercury 150-HP BlackMax outboard engine. They currently have Quicksilver props with a 17-pitch, full marking on propeller reads "Quicksilver 48 16314 A4 17P".

I would like to try a slightly lower pitch, and need some advice on what propeller to buy. I am having trouble operating the boat in rough ocean conditions while trying to plane at about 19-nautical-miles-per-hour. The engines are at about 3800-RPM and seem to bog going up every swell and then the boat falls off plane. My hope is to find a prop that will allow me to operate at 18 or 19-nautical-miles-per-hour steadily and have the engine speed around 4200-RPM where the engines seem to be making a lot more power.

I know it is not very efficient running the boat barely on a plane, but usually heading offshore in the pacific ocean is very rough and I can't operate the boat at 22-nautical-miles-per-hour where it happily cruises. Any ideas or suggestions would be appreciated!

Yes, your older two-stroke engines probably cannot make enough torque at lower engine speed to maintain your boat on plane at lower speeds. Try a lower pitch propeller. Try a four-blade propeller. A stainless steel propeller is probably necessary for best performance.

I think the "A4" is an aluminum four-blade propeller called ALPHA 4. I have tried that propeller and found it was a decent propeller. However, on my boat, with a single 225-HP engine, the aluminum was not sufficiently strong. With 150-HP the aluminum may be strong enough. Dropping pitch will help your engine spool up to higher RPM and give you more torque. If the present propeller are otherwise working well, just drop the pitch by 2-inches and experiment.

Thanks for the feedback, when you say drop the propeller by 2 inches do you mean from 17 pitch to 15 pitch? Or are you referring to diameter?

The propellers I have now are 3 blade stainless

Who makes the A4 propeller that you had?

Sorry I read your post wrong I see that you said pitch.

If looking for better performance, consider changing to stainless steel and not aluminum. This will affect pitch size since size is not universal across brands and models.

I have purchased aluminum diamond 4 Quicksilver props with a 15 inch diameter and 16 Pitch. After talking with my local propeller shop this seemed like a good choice with cost in mind I know stainless would be better, but I want to try the cheaper aluminum props and see what kind of performance I get.... I will update this thread with performance data after the next tuna trip offshore.