Prop Questions

[nwest10]

I'm running a new 200L 4 Stroke Mercury on a Ranger 519 with a Tempest Plus 25P prop with large PVS plugs. Hole shot is fantastic, but at neutral trim I'm getting around 5400 RPM @ 61 mph WOT. Jackplate is set 3" below prop to pad. Should I expect to gain 400 RPM if I drop to a 24P Tempest Plus? Should I consider going to a 23P? I can get more RPM out of it now, but would have to trim up above neutral trim and making it very hard to steer.

Thanks!

[21XDC]

You need to trim up. If you don’t like the steering torque, you might consider a four blade propeller. Speed comes from less wetted surface. You can’t achieve this at neutral trim on a boat like yours.

[nwest10]

So dropping down in pitch won't help me gain RPM at neutral trim? I can certainly trim it up further and gain speed and RPM, but it's throwing a rooster tail 10' high and very hard to steer.

[21XDC]

You might try lowering the motor some and use trim no more than 5ft tail. Lowering pitch will surely add rpms at no benefit.

[Rick Collis]

Lowering the motor on the jackplate will help with steering torque and also the rooster tail.

[nwest10]

Thanks! I'm at about 6 hours on break in. I'll see where it's at when I get to 10 hours and see about making adjustments. Can I just lower the JP, or do I need to drop the motor to a lower mounting on the JP?

[21XDC]

Lower jack plate first. If you don’t have enough room to lower, you may try moving motor bolts down one hole

[nwest10]

Thanks again! I've got lots of adjustment left to go down 2 more inches or more. I'll give that a go and see what it gets me.

[Rick Collis]

I would lower it a 1/4 inch at a time until you find the sweet spot. Good luck.

[nwest10]

Thanks! I'll make small adjustments as I go.