Yamaha F70 Prop Recommendation

[TownsendsFJR1300]

6300 6400? Good God man. When does the rev limiter kick in?

Well, mine, trimmed up is 5900 WOT at about 44MPH.
I usually cruise at no more than 4,000 and will open it up for 3-4 SECONDS (once on each outing) just to make sure everythings fine..

And the boat will jump on plane easily and as fast as the V6, 2 stroke Evinrude it replaced... Maybe 2 MPH slower overall.

To run WOT or such high RPMs, for a long time, no thank you.
IMO, that's just beating the piss out of it and it (or any similar engine) run WOT for long periods of time just shorten the life of the engine..

To each his own, job security for some,


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[Keithbaja]

4000 to 4200 RPM in most cases is the sweet spot for making last forever.. lol I'm running a 19f fiberglass cat with Twin 2003 75 hp 2 strokes. The boat is 1600 lbs (dry) 2 26 gal fuel cells and 56 mph (radar) I meconfess,, I do most of my running at WOT. 5200 on the tach:s. Still a kid in there I quess

[TownsendsFJR1300]

When they re-rigged my boat in '07, they obviously didn't sea trial it. (20'4" ,Angler, CC)

WOT was 5,000 TOPS and ran like a dog with 3 legs. Trim tab WAY OFF. It was REALLY, REALLY BAD...

Went to the prop shop, told them of the spec's and brought down the old prop. Set me up with a new SS prop adjusted for higher, preferred RPMs.
Got it dead nuts perfect the first time...


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[Lumpo414]

The recommended WOT rpm for the F70 is 5800-6300 rpm. I was just stating with 100% throttle and max trim I can reach 6300ish rpm. Im switching to a SS prop with same pitch so should put me down around 6100 rpm at 100% throttle and max trim. You guys are saying 6100 rpm is to high to run with the F70?

[99yam40]

I would not think that to be too high,
the SS usually has more cup to it also.
were those numbers lightly loaded ?

need to check the boat out , loaded like you would normally run it .
people, gear, Ice, gas, etc.

there are props that help lift the stern or the bow , there are props with more surface area or different shapes that do better at certain things

Have you looked up any Yamaha performance Bulletins like I mentioned?

[Lumpo414]

I did look up the performance bulletins it was loaded how it will be 90% of the time. I talked with Andrew over at Simyamaha with my numbers and I got what he suggested.