2010 20sli speed (mph)

[mstonionis]

Hi i have a 2010 benny 20sli equipped with
Yamaha 60 hp high thrust engine
Max speed with clean toons is 17 mph
With algae on em 15 mph
3-4 adults
Fully loaded to spec with adults max speed is 8 mph
My question is this normal ? How can i achieve higher speeds

 

[Jack M]

What's your RPM's at WOT and current prop size , 3 or 4 blade?

 

[mstonionis]

5500 wide open 3 blade its the stock blade for the engine let me look

 

[mstonionis]

5500 wide open 3 blade its the stock blade for the engine let me look

Pitch is 11

 

[Jack M]

I have a "recommended " prop chart that Bennington supplys to dealers. For a 20 ft with a 60 hp is either a 13.8 X 11 or a 12 X 10.5 . Other members may have 1st hand knowledge of that set up.

 

[mstonionis]

I will get down to the dock to verify
On another note how do i determine gear ratio ?

 

[Jack M]

You should be able to contact Yamaha with the serial number

 

[mstonionis]

Thank you

 

[Vikingstaff]

Sounds somewhat correct for performance. There might (might) be a little room to tweak it literally a couple MPH, but once you go beyond 1-2 people with a full tank of gas, it will drop way the heck down on a bi toon with a 60hp. They’re slow cruisers.