V6 150 Merc - safe operating RPM?

[Superjetjim]

Now I have my Tacho sorted and new prop fitted (21p Quicksilver) I wanted to check my RPM's are about where they should be - I'm seeing a smidge over 5,100 RPM flat out at 46mph pushing a 19" heavy deep V ski boat - hole shot is great and I normally cruise at 4,000RPM at 35MPH.

Is this inline with what I should be getting out of my motor?

Cheers,

Jim

 

[1nebel0]

Re: V6 150 Merc - safe operating RPM?

If it were my boat I would set down to a 17" prop...The rpm's will be around 5300 which is closer to where they belong, and you will put up even a better hole shot and more speed given the increased rpm;s. You are close to lugging the motor as it should hit 5500 rpm...just my opinion...

 

[saumon]

Re: V6 150 Merc - safe operating RPM?

I disagree! Changing from a 21p to 17p will roughly give you 800 more rpm, wich translate to 5900. I'd try with something like a 19p first that should put you around 5500 rpm.

 

[1nebel0]

Re: V6 150 Merc - safe operating RPM?

Whoops... I stand corrected....I meant to say 19...each inch of pitch will drop you around 200 rpm...17 pitch is too low.............