prop pitch

[bigcountry5585]

I have a 1976 evinrude 35. It has a 10x13 prop on it now. If I switch to a 10x14, will I gain speed but lose out of the hole?

 

[jimmbo]

Re: prop pitch

you may go faster or slower, but probably be almost the same as now at a lower RPM. However, you definitely will lose hotshot. Do you have any idea what RPM the motor is turning at WOT with the current prop?

 

[steelespike]

Re: prop pitch

What Jimmbo said.
Your results would depend on your present performance with the 13.
Before making any prop change you need to tell us about your boat and your present lightly loaded wot rpm and gps speed.
An induction tach is reasonable and easy to install,many cells have a gps app.
Its important for your motors health and performance to be able to operate within its wot rated rpm.

 

[bigcountry5585]

Re: prop pitch

I have no clue what the rpms are but at WOT I'm running 31 mph. Its sluggish for abot two seconds out the hole but when it grabs its gone!

 

[steelespike]

Re: prop pitch

If your speed is by gps at 31 mph,12% slip 1.93 gear ratio 13" prop your rpm is about 5500. We are guessing at a reasonable 12% slip.
In 76 the rpm range is 5000-6000 rpm. It would be hard to be anymore perfect. With the slightly small motor I think a 1" increase
could knock up to 300 off the rpm making any speed change a wash.It would also make hole shot slower and more sensitive to added weight.If your prop is original just changing to a new Solas or Turning point same pitch may add a little speed.

 

[bigcountry5585]

Re: prop pitch

Thanks for the info. I'll just stay with what I have then. SS prop be worth buying?

 

[jimmbo]

Re: prop pitch

Just my opinion, No. Your likely to see little, if any improvement.

 

[steelespike]

Re: prop pitch

Thanks for the info. I'll just stay with what I have then. SS prop be worth buying?

The Turning Point and Solas aluminum props may add a little speed. For a reasonable cost. Especially if your prop dates back to 76.