new Yamaha 50 ideal wot rpm

[SCO]

Bcakground:This motor has a max rpm spec of 4500 to 5500. fully loaded and into the wind on laborday It was turning about 4800 rpm. Usually, under usual conditions, I notice it runs right at 5000 - 5050 rpm. <br /><br />I have up to now presumed that 5000 would be the ideal compromise wot rpm because you wont be stressing the motor like you would if the motor was propped to deliver 4500rpm at wot, and youll get better speed at 5000 rpm than if you selected a prop for wot at 5500 rpm. <br /><br />In other words , typically, <br />1) do you get better engine life if propped to turn 5500 rpm at wot, and better speed if propped to turn 4500 rpm at wot? <br /><br />2)What is the ideal target rpm considering engine life and top end speed for this motor?

 

[WillyBWright]

Re: new Yamaha 50 ideal wot rpm

That must be a 2-stroke. They love RPMs. The closer you are to the upper limit, the more the motor likes it. I like to shoot for the upper number with a light load. That keeps you in range if you load a lot of beer and people in it.

 

[rodbolt]

Re: new Yamaha 50 ideal wot rpm

if you normally load a lot of people and beer prop it at the normal load, if you pull skiers prop it so it is capeable of 5300-5500 with a load and the skier. two strokes really really dislike lugging. in fact they have a tendancy to shed piston pieces due to detonation. I usually shoot for the top of the range with 2 people and a full fuel tank. gives a bit of room for the boat to get heavier as it ages

 

[SCO]

Re: new Yamaha 50 ideal wot rpm

Im thinking about getting a 14 pitch prop. Am in the breakin though, running double oil. Will the rpms increase after a few more hours, or is this what I'm going to get(4700-5050rpm max)with the current prop? Should I wait a while before getting a new prop?

 

[bigbrownbuku]

Re: new Yamaha 50 ideal wot rpm

i would also reprop. target rpm should be 5500 with a normal load.