60hp yamaha 4 stroke

 Hey everyone,

after some advice, I recently changed the prop on my o/b and it went from 24 knots at 5700rpm to 24 knots at 4900rpm, it's the same prop and was the one recommended, but it didn't have any more in it though, it was choppy and windy today when testing it, the only thing I have done is fixed the speedo pipe and connected that and cleaned the hole for the speedo out would this change the rpm reading at all? 

Any advice appreciated 


Posts: 812

Date Joined: 09/10/06

 Why change it if its the

Sun, 2015-02-15 20:37

 Why change it if its the same prop? or is it the same brand but different pitch?

Rmps arent measured from the speedo tube.

 

Quent85's picture

Posts: 2

Date Joined: 16/09/14

 The prop that came on the

Sun, 2015-02-15 21:20

 The prop that came on the boat when I bought it was buggered it was bent on the ends and chipped, it worked But was needing replacing, it's same size and pitch just good condition

Posts: 315

Date Joined: 07/05/11

4900rpm is working too hard

Sun, 2015-02-15 21:30

something not right there. Did it sound ok

ask tony at jetpower if ur metro

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 Baron Sportsman

Just the depth that Varies

Posts: 114

Date Joined: 16/10/10

 Mate is it exactly the same

Sun, 2015-02-15 23:04

 Mate is it exactly the same prop? Are the dimensions (dia and pitch) exactly the same?

Are you at wide open throttle for the 4900 reading? Or did you just do the revs for 24 knots.

If WOT then Travis is spot on, 4900 is too much work, unless you have a lot of extra weight in the boat. Were your tests done with identical loads/conditions?

Standard  props from my experience generally slip a reasonable amount at high revs, leading me to think the one you replaced may have been the same pitch, but with a better design that grips much better up in the revs,

 

Cheers, Craig.

MandurahMatt's picture

Posts: 613

Date Joined: 18/09/13

im no expert but if the old

Mon, 2015-02-16 16:04

im no expert but if the old one was in that bad a shape could that cause it to slip more than the new one?

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 Bewdey Fellaz