Raker Prop Question

[BigWalt]

I have a Raker prop on my evinrude now. I've looked all over this prop for the pitch and can't find it. All it says is Raker. Any suggestions. I'm installed a jackplate and I'm running higher rpm's around 6000 at 47 mph but i'm wanting to lower the rpms and raise the speed. i would like to get 60 mph out of it. It's an older 140hp evinrude but now sure how old. the plate where the model number is has a scratch on the model number and i can't make out exactly what it is.

 

[BigWalt]

Re: Raker Prop Question

Mine looks like an OMC original raker

 

[John_S]

Re: Raker Prop Question

Someone might be able to help if you give the partial number and indicate which digits are questionable.

If "60" was not a slipped digit, not going to get 13mph increase from a prop change.

 

[BigWalt]

Re: Raker Prop Question

I found it and it's a 13 1/3 x 20P So my question is can I go up or down to get more top speed? It's turning 6000 RPMS at 47 mph

 

[John_S]

Re: Raker Prop Question

I found it and it's a 13 1/3 x 20P So my question is can I go up or down to get more top speed? It's turning 6000 RPMS at 47 mph

You would want to go up in pitch for more speed (with same style prop), but what is your engines recommended wot rpm range?

 

[BigWalt]

Re: Raker Prop Question

I was informed that it was 5500 rpms

 

[John_S]

Re: Raker Prop Question

I was informed that it was 5500 rpms

If that was with normal load and prop was not slipping because the jack plate was too high, you should go up 2-3" of pitch with the same type prop.

 

[steelespike]

Re: Raker Prop Question

What boat are you running?length,weight ,is it considered fast?
47 @ 6000 seems to indicate over 17% slip.very high or your tach is wrong.
this is based on 2.00 gear ratio for a 1980s motor.
5500 @ 47 would be about 9% slip a more reasonable number.
You should verify your tach,is your speed by gps?