Yanmar 3GM30F Mixing Elbow and Overheating

May 24, 2011
81
Marlow Hunter 40 Oriental, NC
Tom, I am sorry. I have a YM model. I just picked up on the fact that yours is a GM.
 
May 24, 2011
81
Marlow Hunter 40 Oriental, NC
Yes, they did. It was under warranty at the time if I recall correctly.
 
Jan 26, 2008
50
Hunter 31- Deale
A simple thing - make sure your anti-freeze mix is 50-50 (distilled water-antifreeze); too much anti-freeze will cause an overheat.

Coast Awhile - Hunter 310
 
Dec 9, 2003
55
Hunter 34 Annapolis
Check the output water flow that comes out of the stern of the boat using a measured bucket and a stop watch. Your engine should be delivering ~3 gallons per minute out the exhaust with the engine running at 1400 rpm.
Water flow measured 2.5 gallons in 55 seconds at 1200 rpm. I have not had a chance to run at 3K rpm's for long enough to see if the overheating is resolved.

So far I've inspected impeller, inspected mixing elbow, new cork gaskets on water strainer and ran the water flow test.

I'll let you know if it has resolved.

Thank you,

Tom
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
About the 50/50 mix...... That's genius! How did you know that? I am having a similar overheating problem on my 1989 37.5 legend. I changed the impeller, and was getting ready to go after the mixing elbow and possibly the HE. I had the marina winterize and spring commission the boat. The coolant mixture looked "thick" to me, but I figured they knew what they were doing. As always, this forum never disappoints.

Ben
 
Feb 26, 2004
22,972
Catalina 34 224 Maple Bay, BC, Canada
About the 50/50 mix...... The coolant mixture looked "thick" to me, but I figured they knew what they were doing. As always, this forum never disappoints.
"diesel mechanic" = oxymoron

If you find a good one, let us know.
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
I have used the same person for two years, now. He is an excellent mechanic and systems installer, etc. I try to do as much as I have time for as well as trying to learn as much as I can. That said, I want to sail more than I want to spend time fixing, so I ask for help fixing. If you want his contact information, I can send it to you. He is based in Annapolis area, but travels to the eastern shore frequently. We are in Rock Hall, MD.

Ben