In my HUnter H376 (Yanmar 3h) I have raw water up to the impeller, but nothing out the exhaust. Impeller looks fine.
Any ideas??
Any ideas??
No raw water output in exhast
- Thread starter rfrye1
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This may help
Among the interesting little “tidbits” of information that I’d remembered reading about on the C34 website had to do with cleaning out the raw water intake with a dinghy foot pump. On a nice mid-winter March 2008 sail with Ken Heyman, who was here visiting, we had just left the South Beach Marina and were motoring over to see the “Lady Washington,” one of the tallships that regularly visits the Bay Area and has cannonball encounters of the close kind with fellow tallships. Since it was cold out, there seemed to be a bit more white smoke from the exhaust than usual, which I attributed to the lower air temperature. Upon checking the temperature gauge, we noted it was pegged and stopped the engine immediately. Ken and I went through a checklist of actions we could take. Sailing back to the marina was not among them, since there was no wind and the end of the ebb was setting us north towards the Bay Bridge. Thru hull strainer clear – check. Raw water entering – check, but a trickle and less than expected. Raw water pump impeller in one piece – check. Raw water pump turning – check. Spare raw water pump gasket to replace cover – check. Temperature gauge working properly – check. Hoses and thru hull clear – hmm… We got the dinghy foot pump out from the lazarette, replaced the strainer and opened the seacock. Because the arrangement of the hoses and the strainer on “Aquavite” aren’t configured to connect the pump there, we removed the hose from the raw water pump and used the dinghy pump at that end of the hose. That turned out to be actually be easier than trying to work under the head sink. There was significant resistance at first, but after setting the three way valve on the foot pump to a higher pressure setting, the pump started working. Whatever had been clogging either the thru hull or the line was flushed out. Once everything was reassembled, we started the engine and all was well. Lesson Learned: It pays to read the material on the C34 website because you just never know when you’ll be faced with an insurmountable problem only to find out that one of our skippers had “been there – done that” and had most importantly reported it for all of us to know. Thanks to Ken for his analytical assistance!
Among the interesting little “tidbits” of information that I’d remembered reading about on the C34 website had to do with cleaning out the raw water intake with a dinghy foot pump. On a nice mid-winter March 2008 sail with Ken Heyman, who was here visiting, we had just left the South Beach Marina and were motoring over to see the “Lady Washington,” one of the tallships that regularly visits the Bay Area and has cannonball encounters of the close kind with fellow tallships. Since it was cold out, there seemed to be a bit more white smoke from the exhaust than usual, which I attributed to the lower air temperature. Upon checking the temperature gauge, we noted it was pegged and stopped the engine immediately. Ken and I went through a checklist of actions we could take. Sailing back to the marina was not among them, since there was no wind and the end of the ebb was setting us north towards the Bay Bridge. Thru hull strainer clear – check. Raw water entering – check, but a trickle and less than expected. Raw water pump impeller in one piece – check. Raw water pump turning – check. Spare raw water pump gasket to replace cover – check. Temperature gauge working properly – check. Hoses and thru hull clear – hmm… We got the dinghy foot pump out from the lazarette, replaced the strainer and opened the seacock. Because the arrangement of the hoses and the strainer on “Aquavite” aren’t configured to connect the pump there, we removed the hose from the raw water pump and used the dinghy pump at that end of the hose. That turned out to be actually be easier than trying to work under the head sink. There was significant resistance at first, but after setting the three way valve on the foot pump to a higher pressure setting, the pump started working. Whatever had been clogging either the thru hull or the line was flushed out. Once everything was reassembled, we started the engine and all was well. Lesson Learned: It pays to read the material on the C34 website because you just never know when you’ll be faced with an insurmountable problem only to find out that one of our skippers had “been there – done that” and had most importantly reported it for all of us to know. Thanks to Ken for his analytical assistance!
Is the engine overheating? First make sure like Stu recommends that your raw water intake is free of obstructions. We have had the instance where water seemed to flow on its own but as soon as the pump started sucking a plastic bag was acting like a flap shuting the flow off. Also you may look for a blocked passage or hose and don't forget the mixing elbow. I replaced my cooling hoses after many hours of service and it is amazing how the salt and other mineral deposits had reduced the interior diameter of the hoses. Also whenever you have an impeller failure make sure you hunt for the broken pieces as they will continue to clog passages.
I had a similar problem where it appeared water was getting to the pump ok but the pump was unable to suck any water in through the hoses because there was a very small air leak in the hose between the seacock and the seperator. I would start by replacing the impellor and then these hoses. These are very cheap things to try before getting in too deep.
If it's..
If it's getting to the raw water pump fine, I'd still verify this by pulling the output hose and placing it in a bucket, then the HX is clogged or the exhaust elbow could be plugged..
If it's getting to the raw water pump fine, I'd still verify this by pulling the output hose and placing it in a bucket, then the HX is clogged or the exhaust elbow could be plugged..
If no obstructions are found after doing as above, it may be the impeller. Just because it looks fine, that may not be the case as these impellers are notorious for breaking at the brass seal -- hub joint such that the hub continues turning while the vanes don't.
If you have free-flowing water at the water pump, that is a good sign the impeller isn't turning properly.
If you have free-flowing water at the water pump, that is a good sign the impeller isn't turning properly.
Same thing happened to us. We checked output of raw-water pump ... okay. Checked flow at different hose connections from there to the heat exchanger, then found that the hose right where it enters the heat exchanger was completely blocked by salt. Cleaned all that out with small wire and flushing with fresh water and problem solved. We were very surprised at the amount of salt build up in the hose.
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