What to set idle on muffs to?

[j_k_bisson]

I'm finally coming to the point in my project where I will be running the resto rebuild on muff for the the first. What I go over everything and set the idle speed/rpm, what should I set it at. I don't want to be at the dock tying up the slip for a half hour.

WHat I am talking about is the manual says to set it in the water to 650 without the boat tied to dock and boat floating freely. So If I set it idling on muffs at 100-200rpms more, say 850rpm. Will this approximate setting get me away from the dock and out on the water so I can set it properly?

What does the in water compared to muffs difference average?

 

[Joe Reeves]

Re: What to set idle on muffs to?

You don't say what engine you're speaking of, however the normal flushette rpm setting depends on the shaft length as follows:

20" shaft = 1000 rpm

25" shaft = 1200 rpm

In the water, the idle rpm will drop to normal (or very close to it) due to exhaust back pressure.

 

[j_k_bisson]

Re: What to set idle on muffs to?

Sorry the motor is a 1987 225hp looper. It is a 25" long shaft. So 1200 rpm is it then?

 

[Joe Reeves]

Re: What to set idle on muffs to?

Yep.... 1200 rpm will do it just fine.

 

[j_k_bisson]

Re: What to set idle on muffs to?

Thanks Joe..... Thanks for the info. I know when it comes from you, it's the right direction.