PowerTech! 13.25 x 14 Prop Performance on a Classic Montauk 17 with Yamaha F70

[@ExtremeDIYGuy]

All the comments have disappeared, I copied one that I thought was very useful, here it is: Against the wind 5900rpm , gear ratio 2.15, prop 14 ", speed 34.1 mph PROP SLIPAGE 6.3 With the wind 5950 rpm, speed 35.1 mph, PROP SLIPAGE 4.3 Very good 08/20/24 Update - Probably needs to be adjusted as the as the gear ratio for this engine is actually 2.33:1, using that then the prop slip is actually -.72% and -3.68% respectively, theoretically impossible numbers but may be real if the manufacturers rated pitch is understated, check out this video for a more recent test run with this prop vs the same size and pitch Yamaha Prop and an explanation of how negative pitch can be possible kzbin.info/www/bejne/qpTbpmqdpJVrrc0

[@dustman92]

Thanks for the vid, I just took an aluminum Solas 15 pitch off my F70. I was having Holeshot issued when I had 2+ ppl on my boat (Key largo 168). I would have to mess with the trim trying to get the motor to find the RPM's, it was lugging bad. Half the time I couldn't get it up and once burned a trim motor up. I went with the Power Tech SCD3 P14. I talked to a few tech who all recommended the same prop, although I was in between the P15 or P14. Ended up going with P14. Installing it today, hope it does the trick.

[@guyanesegamer1693]

You could had stuck a 90 on there I’m planning on putting a 70 on 15 foot wahoo skiff it had 60 originally but the plaque says 80 Max

[@randykaminski6214]

Thank you for the video. I have a 77’ Montauk, and am considering a repower with the Yamaha 70, so your video is very helpful-appreciate it! I’m not a top-speed guy either, but, I thought I read to expect 38mph with proper prop on the same setup .? Is your motor mounted two holes up? Thanks again!

[@ExtremeDIYGuy]

Hi, I do have the motor mounted 2 holes up. From what I have read in Continuous wave and other forums, 35-36 is the expectation, although I'm thinking that perhaps the powertech with the next lower pitch would probably bring the rpm up and maybe the speed as well. I might have to try that this coming year to see what the results are.

[@randykaminski6214]

Thank you, I’m hoping that I stop putting off the purchase of a new motor-currently running a 1990 Johnson VRO 70.

[@randykaminski6214]

Thank you, I’m hoping that I stop putting off the purchase of a new motor-currently running a 1990 Johnson VRO 70.

[@bobtube82]

I'm repowering 1975 16' 7" montauk with F70. I get a Yamaha brand aluminum prop thrown in with the deal. Can you or any of your followers tell me which size to get even if it becomes my backup? Was thinking 13-5/8 x 14 for my horsepower. Also, I am a little worried about SS prop based on lower unit concerns, especially fishing shallows. Your videos have helped immensely and picking up crated f70 next Saturday. I will install following your videos!

[@ExtremeDIYGuy]

I think the prop you are considering might be a hair too much, TBH, knowing how this prop performed, I would go with a 13 x 14 or 13.25 x13. I think that would take the engine right up to it's prime operating speeds. But I believe you will get similar performance with what I got with mine. Maybe a few hundred less rpm since the aluminum blades are thicker. Let me know what you go with and what performance you get!

[@bobtube82]

Thanks! I'm inclined to go with your recommendation. Next size down in the "included" K series prop will be a 13-5/8" X 13 pitch. I'll start with that and go through break-in. I want 2 props anyway and can always adjust after testing this one and keep this as a back-up (if necessary). I'd rather break-in too light and watch RPM's than lug anyway! Once I get results, I'll be happy to share!

[@bobtube82]

Finally got in water. 13-5/8 x13 seems a little too little. Granted only me on boat, but rpms run up quick and was doing 30mph on gps at 6,000 rpm with lots left. 2nd prop will be k series 13-5/8 x 14. Think I have a lead on a good used one in fine shape.

[@aportilla007]

Thanks for posting this video. Did you consider a semi-cleaver design? I have a 1975 Montauk with 90SHO and Im considering the Power Tech SCD3 13x17 prop. Right now I have vented Yamaha Mini Pro 13x19 and it does 38mph at 5300rpm.

[@aportilla007]

I also have a Yamaha 13x19 aluminum prop that takes me to 38mph at 6100rpm. I also have a Yamaha 13x21 aluminum that I am going to try as well, no results yet.

[@ExtremeDIYGuy]

I think the Yamaha prop is a semi cleaver design. I wanted to get as close as possible to the Yamaha prop. is that on a Montauk 17?

[@aportilla007]

@@ExtremeDIYGuy yes Montauk 17

[@colleneswenson8179]

hi can you please give me the part # and prop info for the powertech prop you used

[@ExtremeDIYGuy]

Here's a link to the one that I purchased. kzbin.info?event=video_description&redir_token=QUFFLUhqazBDd1JNZUx0bDBXZktQSW5hZmtLVjNRVEY2d3xBQ3Jtc0tuTUw4STZDTGREZlIwOTBGRlV2V0RzSnZQLVlaN2V0S0lFRUpkNUJfV0M1UnVhSkV5ZnNPeUlnN0dwakRzVGQtc3NIU0pSYlNHQlJlN25QSDFOaDNHTURBVzByallPUV9DY1hyYTdJNHZoZE0xZEZFQQ&q=https%3A%2F%2Fwww.propdepot.com%2Fstore%2FPowertech-RED-3-or-4-Blade-Propeller-70-140HP-Yamaha-p527723020&v=R1OxJ4RpM2g