Hunter 31 - Yanmar 2GM20F Water Leak

Aug 2, 2014
105
Hunter H31 VISA
Hello everyone. I performed a inspection on a 1986 Hunter 31 that I currently has a offer in on. The engine started very easily after sitting for about 10 years. I noticed a steady drip of water (drip every second) during operation from the left back region of the engine. Without a right angle mirror I could not see exactly where it was coming from. I have attached two pictures and included a page from the manual with a red circle from the estimated area where it is coming from. I have a survey scheduled for Monday but just wanted to get a idea in advance if this is a area of comment gasket failure or if this could potentially be a cracked block. Thanks again for all the help.
 

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Mar 11, 2015
357
Hunter 33.5 Tacoma, WA
Impossible to determine from the photos, except the last photo show clear water, and this is a 2GM20F, which should have antifreeze. This makes me think the leak is in the external cooling circuit (salt/lake water). Maybe the exhaust elbow hose connection?

You need a mechanic to definitively determine the cause, meanwhile wine like crazy and negotiate a lower price.
 
Nov 6, 2006
10,108
Hunter 34 Mandeville Louisiana
Like MZ says, could be a lot of different stuff.. Ya need to determine if the "water" is water from outside the boat or water from the coolant (antifreeze) side of the engine. The little valve that you circled is a drain valve to allow coolant to be drained from the heat exchanger housing.. Just above and aft , the little hose that connects from the back of the heat exchanger to the exhaust elbow, same one that MZ is talking about . Sometimes this hose has an anti-siphon valve in it that is a problem child but can usually be cleaned .. Check it and connections and the heatex end caps.. Ya need someone familiar with this engine because that could be $2 or $2000 to fix.. And do whine like ya mean it..
 
Aug 2, 2014
105
Hunter H31 VISA
After using a mirror on the stick I tracked the error down to a hose fitting on the heat exchanger. Easy fix. Thanks for your help
 
Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
Sitting 10 years, possibly with water in the cooling system, I would be very wary of the condition of the mixing elbow. They carbonize and then the engine runs hot or overheats. Not a fun replacement, but I feel a lot more confident when I reach for the key.
 

MitchM

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Jan 20, 2005
1,031
Nauticat 321 pilothouse 32 Erie PA
other negotiating points:

1) check the engine mounts, if they are bottomed out plan to replace them. $500.
2) check the face outs on the prop shaft coupler, if it is out of alignment badly there may be gearbox damage. $?$

3) on sea trial , does the engine hit its power curve?