600 RPM short Question

[Badtracker]

Just bought a 21 ft Party Barge Pontoon with a 2003 Merc 50. Most RPM I can get is 5400. I think the red-line on the 50hp is 6000. Should I try and change the pitch to get a little closer or is 5400 a built in safety factor (I's like to get to about 5700-5800 rpm)?

About how much of a diameter or pitch change would I need to move the RPMs up 400?

 

[rallyart]

Re: 600 RPM short Question

If you drop pitch by 1 or 2 inches you will get a bit better acceleration. For practical purposes it is not a big issue. You need to know the current prop pitch to know what change to make. Keep the same diameter.

 

[Robbabob]

Re: 600 RPM short Question

Realize you have a tiny engine for a large barge ;-)

If you REALLY want to get to higher spec on the RPM, provide details from the sticky at the top of the prop forum page. Art is right about the pitch change; just want the additional facts about your setup.

 

[QC]

Re: 600 RPM short Question

Is that a Big Foot 50? If so it is perfectly fine for this application. WOT RPM is 5500 - 6000, and we really don't need to see 6000 for this application. You are pretty close, so maybe a 2 inch change is all you want. If it is a Big Foot then forget Diameter and go with the recommended. Definitely need to know what you have. In this case, low speed, larger boat, bigger diameter is good and it is why they apply the Big Foot.