F115 prop selection

[malibuguy]

I need some help here with prop selection. I bought a 2002 F115 and installed it. It runs great but i need to get the right prop for this thing. The prop that came with the motor had the inner flange ground off (possibly by a downrigger cable or something ) and my local prop guy said that exhaust was exiting in front of the prop and making the prop slip. So I bought another 13.25 X 17 aluminum prop and tried it yesterday. There was some improvement but it still revs out to 6500 RPM at max throttle and the boat is going 35 knts on my GPS. The boat doesn't get on plane until over 4000 Rpm and my old motor(a 120 HP 2 stroke) got on plane about 3500-3600 RPM. I suspect I need to move up to at 19 pitch but I don't want to buy yet another prop that I don't need. I believe the ratio for this motor is 13:28 (2.15) The dry weight of my boat is 1700 lbs. With fuel, gear and the motor I believe weight is about 2500 lbs. It is a Malibu 182 V hull with 25 deg deadrise. Any thoughts on my next step?

 

[trendsetter240]

Re: F115 prop selection

I need some help here with prop selection. I bought a 2002 F115 and installed it. It runs great but i need to get the right prop for this thing. The prop that came with the motor had the inner flange ground off (possibly by a downrigger cable or something ) and my local prop guy said that exhaust was exiting in front of the prop and making the prop slip. So I bought another 13.25 X 17 aluminum prop and tried it yesterday. There was some improvement but it still revs out to 6500 RPM at max throttle and the boat is going 35 knts on my GPS. The boat doesn't get on plane until over 4000 Rpm and my old motor(a 120 HP 2 stroke) got on plane about 3500-3600 RPM. I suspect I need to move up to at 19 pitch but I don't want to buy yet another prop that I don't need. I believe the ratio for this motor is 13:28 (2.15) The dry weight of my boat is 1700 lbs. With fuel, gear and the motor I believe weight is about 2500 lbs. It is a Malibu 182 V hull with 25 deg deadrise. Any thoughts on my next step?

Is your new 17" prop a 3-blade or 4-blade? If it's a 3-blade then your next prop should be a 4-blade. The 4-blade will give you more bite, help with holeshot and allow you to plane at a lower speed.

Based upon the info you provided, I would recommend a 19" pitch, 4-blade aluminium Solas Amita prop. You can order them from right here on iboats.

That motor should be propped to allow for 5800RPM at WOT with an average load.

 

[malibuguy]

Re: F115 prop selection

The new prop is a 3 blade prop. Maybe the 4 blade is a good idea as it is nice to stay on plane at slower speeds as sometimes in heavy seas you can't make much speed! Anyone else have thoughts?

 

[malibuguy]

Re: F115 prop selection

I ran my boat through the prop selector on the Mercury site and it comes up with a 3 blade 13x19 prop suggested. Anyone have suggestions? Anyone else have a F115 on a similar boat? What prop do you have on it?

 

[smitty477]

Re: F115 prop selection

Malibuguy,
We are seeking similar information for the same engine on slightly different boats. I have an existing setup that I would like to get feedback on before I purchase another prop. Please see my post below titled RIB/115hp/prop selection.
Hope this helps.