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Posts: 186
Location: Kaukauna, Wisconsin | Hope you guys can help me with this. First I'll give the info on the boat... My dad and I fish out of a 17' Lund Angler with a 115 Yamaha on the back. The prop we have on the motor is a 19 pitch aluminum prop. Our speed on the GPS in around 37 MPH, and I do have the motor trimmed up a little bit. The RPM at full speed is right around 5800 RPM and the owners manual says the preferred RPM's is 5500, but the range is 5000-6000. The motor is mounted in the top hole; lowest setting. Now on to the question part, should we be getting more speed out of this rig? Next is when turning at full speed I lose speed and it sounds the prop is coming out of the water, should this be happening and is there something I can do to change it? Finally I have been told that raising the motor can increase performance, is this true? It is a long-winded question, but if you can help me let me know... Thanks |
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
With an aluminum prop, you will be sacrificing a bit of performance. I will say there is no doubt you should be able to get more out of the rig with a 115. With that motor, getting to 6000 rpms when you are on your own is a good starting place. That way, when you do get a second person in the boat, it still performs well enough without a prop change. With that motor, I would bet you could go to a 19 pitch steel prop, raise the motor up two holes and you will see a huge gain in performance and will not have to trim down much for turning. The aluminum prop does not hold water well and flexes quite a bit under load so a 19 pitch aluminum probably acts more like a 17 or 18 pitch prop.
I would suggest trying a 13-1/2 x 19 pitch pro series by yamaha on that motor, but would also say try a michigan ballistic as well. Both props are great props, hold the water well, and will lift the entire boat out of the water which only means one thing...speed.
I will bet the change to steel and moving the motor up will have you smiling from ear to ear...
Steve |
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Posts: 186
Location: Kaukauna, Wisconsin | Thanks for the advice and info Steve!!! |
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Posts: 395
Location: NW WI | Keep an eye on your water pressure when raising the engine. A 4 blade prop could be a good option too.
If you don't want to work with a dealer on your issue, the guys on the Yamaha forum of Bass Boat Central will help you out. |
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Posts: 3508
Location: Elk River, Minnesota | No worry on the water pressure so long as you are within the mounting holes on the engine. With that rig, you could go another inch or so above the 4th bolt hole before you'd have to worry about losing water pressure.
Would not hurt to have a gauge, though...it is one more item to be able to monitor....when the impeller starts to wear, pressure will go down, although if you are changing your impeller every 3 years or so, you shouldn't have that issue unless you run some sand through it...
Steve |
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