best propeller pitch

[boater55]

the stock propeller is a 9.25x 10 (it is three bladed)
does that sound like a good propeller to start with?

 

[Johny25]

A 4 blade will not increase speed, it will take away from top end. Since it is a 76' model and does have the 2.41:1 gear case and RPM range 5500-7000k I would recommend a 3 blade 10 pitch prop if your putting it on a 12' tin. This would probably be a safe starting point to get some info. From there you can adjust in pitch to get optimum performance. But you have to start somewhere and cannot expect to get the perfect prop on the first try with out any data to go by. All we can do is give you an educated guess from our experiences.

If you can turn a 10pitch at 6250-6500rpm you should see numbers around 20-22mph assuming a 15%-18% slip

the stock propeller is a 9.25x 10 (it is three bladed)
does that sound like a good propeller to start with?

Yeah that is what I just said....... the 9.25 is diameter and it has little bearing on RPM performance unless you jump in large increments. So a 9X10, 9.25X10 or a 9.5X10 will be fine. Here is a good site for props at a good price and these will all fit your motor
https://boatpropellers.iboats.com/Evinrude-Outboard-Propellers/?pitch=10.00&chart=7&engine_id=23&cart_id=504378492

 

[highgeardaddy]

Sorry for the stupid question but how do you rig up a tach to check your WOT RPM. Are there automotive tachs. that you can clip on just for these quick water tests?

 

[Johny25]

A typical auto tach will not work on a two stroke. They sell "tiny tachs" for about $50 that read two stroke engines and all you have to do is wrap the wire around a plug wire.

 

[Charger25]

the stock propeller is a 9.25x 10 (it is three bladed)
does that sound like a good propeller to start with?

I would say yes. I've got a 78 Evinrude 15 hp it was turning a 9.25 X 8 prop. That set up got the 16 ft lowe (v-hull) up on plane very well. With approximately 575 lbs ( persons,motor & gear) I was able to out run a bud of mine in a 14 ft with a 8 hp (semi-V) I ordered a 9.25 X 11 prop because I'll mostly be running it on the 14 ft. Haven't tried it out yet though. I agree with Johny25 and IMHO, your 15 W/ a 9.25 X 10 on the 12 ft should FLY !

 

[trevandyson]

I have a 1978 Johnson 9.9 on my 14ft jon, it has a front and back deck so pretty loaded down. I am thinking about putting a 9 pitch three blade on it, do you guys have any suggestions for where to start?