Water Pump Impeller Failure

[Jim Jamieson]

I had an interesting experience today. The hot light and buzzer came on
while motoring with the Yanmar 1GM in my sailboat. In a rocky sea,
I removed the impeller from the water pump and found that the rubber
part had separated from the metal insert that keeps it
rotating on the pump shaft. This impeller was new from Yanmar and only
had 9 hours on it! I've put in a new one but wonder what the
probability of a repeat occurrence is. Anyone out there with similar
experiences or recommendations as to how to avoid it?
jim

[Andrew Turner]

Jim Jamieson <james.j...@yale.edu> writes

Jim,
This problem with Yanmar 1GM10 was widely reported as far back as April
'96 in the British yachting press. Two explanations were offered at the
time :
1) Fitting a marginally wrong-sized (by 0.8mm) Jabsco impellor.
2) A bad batch of genuine Yanmar impellors with the wrong bonding agent
between the rubber and the bronze boss. The UK Yanmar importers offered
a free exchange to anyone with one of the bad ones (like me!).

Sounds like some of those bad ones are still around. Moral - always
carry a spare (and hope it's not bad too).

Other tips - always remove the impellor if laying up for the winter
- replace the old pump cover with a Speedseal cover

Regards,
Andrew.

--
Andrew Turner <atu...@custlnk1.demon.co.uk>

[Garry Elmer]

Wow! You're readin' my mail! We were lucky enoguh to make it to where we
could anchor while replacing the impeller on Tuesday. We have a 2 cylinder
Yanmar in our Hunter with a fresh water/sea water heat exchanger. We have
lost the seawater impeller twice in two years. Our seawater pump is a
Jabsco add-on and the Yanmar pump handles the anti-freeze collant.
Luckily, we were able to keep the engine temerature down by periodically
running the hot side of the fresh water to carry away some of the heat via
our hot water heater. When we ran out of fresh water we got the overheat
but by then we were pretty close to safe harbor. I am going to get a whole
bag of those things!
Garry

http://www.99main.com/~elmergw/

[Dick Bacon]

Jim,
Return the impeller to the dealer. Check you heat exchanger. It may be
clogged and reducing flow thereby increasing heat. Perhaps the
increased heat melted the adhesive.
Dick Bacon
Tacoma Wooden Boat Society