Raw Water Pump Diagnosis
Moderator: Jim Walsh
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Bob Owens
- Posts: 150
- Joined: Dec 3rd, '05, 23:09
- Location: CD 27 (1977) "ABIGAIL"
City Island, New York
Raw Water Pump Diagnosis
My boat sat on in its cradle for three weeks after being hauled, while I made a have-to business trip. The raw-water intake pump has always worked flawlessly, with a new impellor installed each spring. When I set about yesterday to winterize the engine, the pump initially had no vacuum pressure. I took off the speed-seal back to check that the impellor was ok, and reassembled. Also tightened the (rather new) belt a notch. Then it sucked fine--for about three minutes. I got 5 gals of fresh water through and one jug of antifreeze; then the pressure slacked off. Intermittent pressure then got two more jugs of antifreeze through, enough for my YSB8 so I quit. Come spring, I will install a new impellor, of course, but in the meantime I wonder if there is a more serious problem that I need to be anticipating. When it was working, the vacuum pressure was very strong, as usual. Any ideas about what would make the pump, that worked perfectly all season, suddenly go fluky when the impellor looks fine and the belt is good? Thanks.
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Duncan Maio
- Posts: 180
- Joined: Feb 5th, '05, 22:01
- Location: Cape Dory 27
Impeller
Bob:
A number of years ago, there were reports of impellers going bad right out of the box - the rubber part separating from the bronze hub. You might also have a blockage of some sort in one of the hoses, that is cleared when the hose is moved around (when you move the intake in and out of the jugs of antifreeze, for instance). The only other possible culprit is the SpeedSeal o-ring.
Many Yanmar owners - myself included - have switched over to Globe impellers - the blue ones - and had no problems.
A number of years ago, there were reports of impellers going bad right out of the box - the rubber part separating from the bronze hub. You might also have a blockage of some sort in one of the hoses, that is cleared when the hose is moved around (when you move the intake in and out of the jugs of antifreeze, for instance). The only other possible culprit is the SpeedSeal o-ring.
Many Yanmar owners - myself included - have switched over to Globe impellers - the blue ones - and had no problems.
Duncan Maio
s/v Remedy
CD27 #37
Bristol, RI
s/v Remedy
CD27 #37
Bristol, RI
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Ray Garcia
- Posts: 258
- Joined: Apr 27th, '05, 22:08
- Location: 1981 CD27 #212 "Spirit" Huntington, NY
- Contact:
Check your thermostat. From your description it may be faulty.
When I winterized my CD27 with same YSM-8 I noticed the water not pumping after I started the motor. Though my thermostat is good, the water will not pump through until engine comes up to temp. The combination of antifreeze/water temp going in, load on motor, and ambient temperature may also affect the circulation.
When I winterized my CD27 with same YSM-8 I noticed the water not pumping after I started the motor. Though my thermostat is good, the water will not pump through until engine comes up to temp. The combination of antifreeze/water temp going in, load on motor, and ambient temperature may also affect the circulation.
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Bob Owens
- Posts: 150
- Joined: Dec 3rd, '05, 23:09
- Location: CD 27 (1977) "ABIGAIL"
City Island, New York
Thermostat
I always remove the thermostat when I winterize, so that I don't have to wait for the engine to warm up for the antifreeze to flow throughout. It was out when I experienced the on-and-off performance of the pump yesterday.