Prop help??

[rodbuilder]

Hi all. I have 1775 Pro-V tiller with a Pro-60 Yamaha. The current prop is a 13.5x16 and the motor is running 4400-4500 RPM at WOT, giving me 22-23 MPH. I have been told that optimum RPM range for this motor is 4500-5500 RPM. So, I have 2 questions, what size prop would you use for this set up and what is a realistic goal for top speed? Props are expensive so when I buy one, I don't want to buy the wrong one and throw motor performance out the window.

Thanks!!

[Fishing Junky]

Hey Rodbuilder. Is this a new boat to you? If so, are you familiar how to use the trim on the motor? 22-23 seems awfull low to me. Are you trimming up enough? This is a start, Junky..........

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A fishing guide is just a fishing junky who takes others with him to support his habit.

[Granny]

Check out Jay's page and give him a call. He should be able to help you and offer you a pretty good price if you want a new prop!

www.soderbloom.com/proprepair

Granny

[Moose-Hunter]

Hey there, rodbuilder...

I have to agree with The junky on this one. Your MPH seems slow to me as well, even with the stock prop, if that's the one you mentioned. Is this speed reading done with an on-board speedo or GPS? How easily does your boat plane out? Are you loaded down to capacity? And, not meaning to be a "killjoy", but are you under-powered? Is your 60hp enough for a 1775?

I could go on and on with info I found out about props in my own "hunt for the perfect prop" for my Yamaha 75. But basically, to raise the RPM +/- 200, drop the pitch by 1" or reduce the diameter by 1/2". Typically, when you raise the RPM (dropping the pitch), you gain holeshot, but lose top end. But I feel in your case you may even raise the top end due to the reclaimed motor speed. I've seen it happen.

A realistic top speed.... That's a tough one. Without actually seeing your boat, knowing it's weight and how things are set up, I wouldn't have a clue.

rodbuilder... I'm no prop expert by any definition. It cost my close to a grand in trial and error, to find my "perfect prop". This being said, I would suggest that with all the variables involved with props... Diameter, pitch, material (aluminum or stainless), blade design (flat, semi and fully cupped), blade rake. Not to mention all the variables thrown in from your boat.... Your best bet is to find a marina or prop shop that will work with you and allow you to water test a few different combinations. Sure, it's a hassle and you basically waste about a day of fishing time, but, trust me on this one, it will save you money and headaches in the long run.

Just make sure that when/if you do this, you have your boat set up as it would be for a typical day on the water (gas, equipment, occupants, full live well), that you know how and when to properly use the trim and that your motor is in tip top running condition.

Hope this helped a bit....

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M-H (aka: Dan)

[rodbuilder]

Thanks for all the info guys! I have an appointment at a dealership on Saturday to have it looked at. The mechanic at the dealer is suspicious about the accuracy of my tachometer so they are going to hook up theirs and see what the engine is really running at. I cannot disagree. Its a Yamaha tach but who knows how accurate. FYI, the boat is rated for a 75 HP max, so with a 60 I am a little under. Not sure about the trim question. This is the first boat I have owned with power trim. I just keep lowering it until it sounds good and my speed is at its max. I know i have went too low when the speed starts to drop. Not sure what the weight of this boat is but I know its heavy (at least compared to my past beaters). Also, the speed was checked with the X-85. I am going to check it with the GPS tonight.

Thanks for all the input!!...and if you have anymore ideas, please pass them along!

[Surface Tension]

You should be lifting the motor not lowering it after your on plane.
Have your tack checked out because everything about prop selection revolves around your RPMs at WOT.

[vikes40for60]

Trim it up and watch your RPM's climb. The speed paddle on the X-85 is very inaccurate. The GPS reasing is the only way to go for an accurate speed.

[Northlander]

Call Jay Soderbloom and he can help ya out and get you props at the best price around! www.soderbloom.com

[rodbuilder]

Hi guys. OK, here is the story. I found out 2 things last night. At WOT, motor trimmed up until just before it starts cavitating, I got 29.1 MPH on the GPS. Sound better? Also, that stupid Yamaha tach...at WOT when I wiggle the wires, the display comes and goes and the RPM's jump all over the place . I am gonna go through that wiring at the gauge on Sunday. Does anyone know where that connects to the motor or is it connected to the battery and is just reading alternator output? Thanks again for all the help! Another thing I found out. This prop is stainless, not aluminum. Its painted black so I just assumed it was aluminum as I have never seen a pained stainless prop. When I took it off it was obvious that it wasn't aluminum (heavy!). How long does it take for prop repair? The edges are pretty beat up/gouged. If i get the prop rebuilt, I may be able to achieve 30 MPH!

Later!

[Fishing Junky]

That's sound WAAAAAY better rodbuilder. Still wish I knew what you were taching though? If your rpm's are still low, you could have a little pitch takin' out when you get it fixed. If your taching a little high, a little cupping might help. Fixing your prop will definitly help your performance. As far as how long it takes to get fixed, depends on how busy the prop doc is busy. Good luck and good fishin' to ya. Junky.................

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A fishing guide is just a fishing junky who takes others with him to support his habit.

[Malachi]

If you want to get up on plane a little quicker it will probably help to go with a lower pitch on your prop. You mentioned you are considering getting some work to your existing prop. If it is an aluminum prop the repair shop should be able to change the pitch 2 degrees. Stainless props can usually be changed 1 degree. The repair shop here in town charges around $25.00 to change the pitch if the prop does not require any repair. I would think it may be less if they are already working on the prop.