Yamaha F70 prop and setup

[Fowlmouth30]

Recently moved from a 2 stroke Mercury 50 to a 4 stroke Yamaha F70 on a 1650 side console triton. Mounted the motor and was considerably unimpressed with the performance. First run was only pushing about 30-31 MPH and bouncing off the rev limiter, no matter of where the motor was trimmed so I believe it was too low. Raised the motor two holes and the foot was blowing out so i moved it down to the middle holes. Also finally got the engine interface cable to be able to read RPMs on the graph. Currently running the original 13-5/8” 13 pitch aluminum prop and turning around 6k RPMs, with 6250 being on the rev limiter and still only getting around 32 MPH. Should I consider a jack plate to help fine tune the setup? What pitch prop would the brain trust recommend?

[Coastal Woodie]

You might be better off with a 16 or 17 pitch.

[kquinn]

X press 1756 side console
Mounting hole is 2nd from top
13 pitch PowerTech
37 mph

[Fowlmouth30]

X press 1756 side console
Mounting hole is 2nd from top
13 pitch PowerTech
37 mph

Same motor?

[Sheep]

I'd try a 17 ybs or similar...

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[Sheep]

Actually, I have a 19 ybs you could try....it may be a little much, but would give you an idea of how a 17 would run.

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[Fowlmouth30]

Actually, I have a 19 ybs you could try....it may be a little much, but would give you an idea of how a 17 would run.

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I may take you up on that. Shoot me a pm when you get a minute, your inbox is full

[Sheep]

I may take you up on that. Shoot me a pm when you get a minute, your inbox is full

Text me. 864 fiveoh5 5828

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[kquinn]

Same motor?

same motor

[dixiedeerslaya]

If you are bouncing off the rev limiter, no amount of engine moving, jack plating, or tinkering is going to get you much faster. You can only pedal a bike so fast in first gear.

Go up to a 16 or 17 pitch prop and see where you are at. You may need to even go up to a 19 if you are looking for unloaded performance.

[billbuster84]

I will chime in. Had a Yamaha 70 2 stroke on a 1648 tracker, tiller steer. 17p stainless would run 38-40 loaded, 40-45 just me. 19p would get a little more top end, but wouldn’t tote the load as well. Buddy had a 17’ express with the F70 and a 17p stainless and it was 36 mph loaded or not


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