Join Date: Jun 2006
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2GM20F - Fresh Water Circulating pump
I need some information about the fresh water-circulating pump on a Yanmar 2GM20F.
Last weekend while mooring my IP-27, the engine had a C W Indicator/horn came on and I shut it down within 5 seconds. Opening the cockpit engine compartment hatch a strong odor of an overheated engine and coolant greeted me.
The engine had been running about 15 minutes at the dock before the short trip to the mooring. When the engine cooled, I checked the coolant level, there was none to be seen in the heat exchanger. It was late, I shut everything down and I did not pursue the issue till today.
This morning I went out to the boat and added about a quart of distilled water which brought the coolant level back to normal. I checked the engine oil level which was fine.
The engine was started without difficulty and I ran it for 2-3 minutes and then shut it down. Rechecking the coolant level showed a small decrease in levels and a bit more water added.
On the second start it ran but there was an intermittent noise from the front of the engine and I shut it down once more. Again I checked the coolant level and added a small bit more water when it had cooled off.
The third time I started the engine, there was a persistent noise from the front end. I saw the pulley wobble for an instant and then there was a high pressure stream of water/coolant/and some brown 'liquid stuff' spray the area of the fresh water pump and even reach out of the engine compartment onto the cockpit seats. Again I shut it down, checked the coolant and added a tad more water.
All belts were checked and found to be tensioned correctly. The raw water pump was functioning normally and putting out it's usual volume of water which varied with the throttle setting. All hoses were also checked and found to be OK (If it had been a hose malfunction, there would not have been the loud noise from the engine.)
From what I have seen and heard from the engine, I feel it is the fresh water-circulating pump not functioning.
My question is in several parts:
1) What tests can I run to make sure that the issue is the FW pump?
2) How difficult is it to take it off and put it back on? (The access, unlike most of the rest of the engine, is very good.)
3) Once it is off the engine are there things I can check and possibly replace parts or should I just bite the bullet and get a whole new pump. (I do not have the shop manual for the engine but plan on getting one during the week).
Since this is a very popular engine series (original engine on my 1985 ip-27 # 41) I was hoping there is a lot of background information available from our members.
That’s the story, folks. Any offerings will be greatly appreciated.
Thanks to the Group in advance,
Bill R on Sun Dancer