Yanmar 2GM for 31'

[Robert]

What is the recomended cruising RPM for the Yanmar 2 GM on a 86' Hunter 31. I think it is 16hp

 

[Mike]

Depends...

Prop size/ 2 or 3 blade. I have the same boat and have cruised all day at 28-3000 RPM's with no problems. You will burn about 1/3 Gl per hour at his setting.I have cruised for 2+ hours at 3200 and all seems fine. The speed doesn't seem to go up much past 6 knts at 3200. Hope this is a start. Be sure to read your Yanmar manual for details on staring and stopping the engine.

 

[Steve Dion]

70-80% of max.

Robert:The Yanmars are recommended to run at 70-80% of the max rating. I believe that your max rating is 3600 (check the plate on the front of your engine). This puts you around 2500-2900 rpms. If you run at lower rpm's for extended periods of time, it will promote the build up of carbon in your mixing elbow. If you run higher that this for extended periods of time the engine may overheat.You should be able to get the max. (3600) out of your engine while in gear. If you cannot you may be over propped. If you cannot get the max rpm's while out of gear you may need an adjustment of the governor or some other fuel problem.This subject has had extensive discussion in the past, so you may want to look in the archives for more detailed discussions.

 

[Dick Carey]

2GM20 Crusing

Our 2GM20(F) cruises nicely at 2800 RPM. You can run it higher but not much increase in boat speed thru the water. It seem to 'like' that rpm setting.Dick CareyS/V Puffin1990 H-33.5

 

[Mark Smith]

Cruising rpms

My 2gmf loves to be run at about 2800 rpms. Yes the 2gm is rated at 3600 rpms but running at this rpm will do nothing but shorten the life of your motor,as I am told by pro deisel mechanic.

 

[Jerry]

Agreed

I have the same boat and 2800 seems to be the RPM's the boat and motor like. Even when motor sailing.