2120 prop size

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I just purchased a power tech 15p four blade from my 2009 2120 with a yamaha 150f. I had a ss 16m three blade that was from the factory. I need more hole shot and really don't care about top end. The 2120's are battle ships that take a little more lift and push to get on plane quicker. After a lot of research and reading I think this change will help but it has been way to cold to test her out.
I am lucky to have a great prop shop that will back their work and replace for a different pitch if needed during testing. Hope this helps.
 
Gobbler66":1o98qjgh said:
I just purchased a power tech 15p four blade from my 2009 2120 with a yamaha 150f. I had a ss 16m three blade that was from the factory. I need more hole shot and really don't care about top end. The 2120's are battle ships that take a little more lift and push to get on plane quicker. After a lot of research and reading I think this change will help but it has been way to cold to test her out.
I am lucky to have a great prop shop that will back their work and replace for a different pitch if needed during testing. Hope this helps.
Click to expand...

Curious did you have a chance to get your new prop wet yet? I have read good things about the 14 1/2 x 15 3 blade prop but I'm holding out to get some data on the 4 blade??
 
Kilowatts":2tmv2fsr said:
Gobbler66":2tmv2fsr said:
I just purchased a power tech 15p four blade from my 2009 2120 with a yamaha 150f. I had a ss 16m three blade that was from the factory. I need more hole shot and really don't care about top end. The 2120's are battle ships that take a little more lift and push to get on plane quicker. After a lot of research and reading I think this change will help but it has been way to cold to test her out.
I am lucky to have a great prop shop that will back their work and replace for a different pitch if needed during testing. Hope this helps.
Click to expand...

Curious did you have a chance to get your new prop wet yet? I have read good things about the 14 1/2 x 15 3 blade prop but I'm holding out to get some data on the 4 blade??
Click to expand...

Opps, I looked at your join date and saw September and thought that was your message post date. Please let us know when you get the new prop wet!
 
Due to this brutal winter I was able to finally get out and test out my new 4 blade 16p propeller. I now have a problem. My WOT readings are a little hard to believe at 34mph 4300 rpm.
The original 3 blade 16p wot was 37mph at 5700 rpm. Could I have really lost 1400 rpm by going to my 4 blade 16p power tech?
 
Something is not right with those numbers. You can plug in your data using a prop slip calculator like this one.....

http://www.mercuryracing.com/propellers ... ulator.php

Your 3 blade setup shows 14% slip, while the 4 blade is negative, which is not possible :D

Loosing a couple mph with the 4-blade doesn't surprise me and based on your speed (assuming GPS based), I would suspect the tachometer is faulty. Toss the 3 blade back on just for fun and see if your RPM's still read low. How does the engine sound at WOT? You would certainly hear a big difference between 4300 and 5700rpm's!
 
I visited Max yesterday at Bay Propeller in Chesapeake where I purchased my prop. Max became curious of the serial/model numbers and decided to measure the prop himself. The prop turned out to be a 18 pitch and there was the culprit. I was worried that sometime had happened to my tach but he said the pitch would cause this to happen. He apologized and immediately got on the phone and ordered me the correct prop and is having it drop shipped to my doorstep.
I am a very satisfied customer and Max is great to work with. The serious drop in rpm's scared me a little.
 
Curious how this works out...... That's a lot of RPM's to make up for an engine that should spin close to 6k at WOT.
 
I am hoping to receive the new prop by the end of the week. If that is the case and the weather holds out I will take her out again on Sunday. I will report the results soon after. My fingers are crossed but I agree that difference in rpms has me worried.
 
Today the UPS man showed up with my prop as planned. They sent a 15.25 X 15p power tech polished stainless steel 4 blade. Ok, now I'm again worried before I even put it in the water. This prop is big and heavy! I have been working this keyboard tonight trying to see if this diameter prop is even going to work on my Yami f150. Some say yes and then some said no its not recommended swinging that much blade on my motor. Typical results for web searches on any subject matter. :wink:
If anyone out there has run this diameter blade on a Yami f150or have any experience on this matter please let me know.
I don't think it is going to hurt the motor so I might go ahead and give her a spin "so to speak" tomorrow or Sunday.

Markman - My motor is mounted using the 2nd from the top hole. This has not been changed since the factory.
 
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