April 8, 2013

Yanmar 3GM30F Raw Water Pump - Rebuild

Just before we left to go sailing on Moreton Bay, I rebuilt the raw (sea) water pump with spare parts I had bought in San Francisco, some 2-1/2 years ago.  New bearings, a lip seal, a new impeller, etc.

If you take your old bearings and lip seal to a bearing supply house they can supply generic replacements for about 1/4 of the cost of Yanmar parts.  Just make sure your lip seal has a s.s. spring or an O-ring.  It's not hard work really to do the rebuild, once you realize the 2 bearings have a circlip between them and you have to seperate them to get them off the shaft.

And when you put the pump back togther - the pulley is not symmetric.  It's dished on one side. If you put the pulley on with the wrong face facing the pump, the V-belt won't line up.  At all. Though you can convince yourself that all is well if you're trying to go sailing for a long weekend.  And motor for many hours with the pump working with a V-belt that is totally off by about 1 cm or more.  When you put the pulley on the CORRECT way it looks much nicer.


7 comments:

Anonymous said...

makes one wonder how you found that out ........... I've never done that.

builder said...

You can get a brand new pump at half the cost of the original Yanmar. Try www.depcopump.com. I got one for our 3GM. Just add grey paint. They are in fact Johnson pumps, nothing really Yanmar-ish about them (except the price).

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Anonymous said...

jsut rebuilt mine after I noted dripping water from the housing side, not the impeller plate side.
Bearings were perfect still, new seal installed (a single yanmar part that is actually 3 parts) and new impeller and o-ring for the palte, and it is perfect! Bought a spare (as I do every time I need a replacement or maintainence part).
Next up the exhaust/mixing elbow...

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