poor performing yamaha 4 stroke

[steelespike]

Re: poor performing yamaha 4 stroke

Yes a vented prop may help.Maybe kill two birds with one stone.

 

[astrobass1]

Re: poor performing yamaha 4 stroke

I have ordered a pro 19 p prop and going to stick it on this weekend ,Vented I cannot find easily have a new belt coming as well. The boat has recorded 27 hrs on it.so it is as close to factory as can be . Thanks for the help more on Friday.......

 

[steelespike]

Re: poor performing yamaha 4 stroke

fingers crossed.You may want to check what the belt drives.The old Ford Escorts belt would squeal if the pump was failing.
Obviously nothing to do with an outboard just have to wonder at 27 hrs. why is it squealing.Just stretched?

 

[astrobass1]

Re: poor performing yamaha 4 stroke

Well guys, bought the prop Yamaha 19p pro and got 53gps MPH definatly the prop made the difference!!
does anyone recommend ethanol free gasoline on 4 strokes?

 

[sasada]

Re: poor performing yamaha 4 stroke

Absolutely....if u have the choice, never use ethanol in a marine application. If you dont, marine formula sta-bil 100% of the time.

 

[steelespike]

Re: poor performing yamaha 4 stroke

What a pleasant surprise!
Prop calculator says 6500 rpm. to get 53 mph. ??
I'm going to double check gear ratio.
ratio checks out?Is 53 a missprint?

 

[smitty477]

Re: poor performing yamaha 4 stroke

"Prop calculator says 6500 rpm. to get 53 mph. ??"

No need to recheck - you are absolutely correct as you helped us with a similar application 2 years ago.
The gear ratio is 2.15:1 and at 6,100 rpm's and a very small slip on our boat we saw about 48 mph max.
That was on a very light RIB on a perfect day.

Hope this helps