Yanmar 1GM water pumps

[bill good]

Just though I would see if anyone has ever rebonded these impellers?

Was working with some glue used repairing a Zodiac & though it might work so a rebonded impeller is under test.

The cost of replacements for the past 14yrs for this one item has been at least $1500.00 for two engines.

Bill

[atoll]

how does that compare to the price of a new head gasket if it fails

[bill good]

I have been changing these impellers every 12 mths & run the engines weekly. The temp warning is very close to normal operating temp which is what will save the engine. This is an on going 1GM problem for salt water by my experence. Maybe plumbing a fresh water wash in the system may also help. I just though someone may have tried to rebond one that failed early in its ops.

[Acushla]

I guess the you mean the cost has been $1500 for a total of 28 impellers over 14 years on a yearly replacement policy? That is not a major expense considering the risk of failure of a repaired impeller which is almost bound to happen at the least opportune time.

Acushla

[bill good]

I would not even be trying if the replacement once a season worked but it has not. I put this out for response from people who know & love 1GMS. The bonded repair looks good & time will test that. Most of the failed impellers don't have any amount of wear on the blades!!

Regards

[Andrew Troup]

Hmm.. I'm doing up a 1GM as a standby motor which has to be ultrareliable. I'm thinking of fitting an external water pump, bypassing the built-on item.

If the people who supply OEM for Yanmar can't get the impeller to bond reliably in the first place, I'm not sure I fancy my chances of doing a better job. I don't suppose there's any 'aftermarket' supplier?

I've been foster parent to a 23' trailerable offshore sailboat with a 1GM-10 for the greater part of the last two decades, so I can understand your affection for this motor - it's a wee sweatheart.

This motor would only have done a few hundred hours, certainly well under five hundred - both the owner and I prefer to behave as though there's no engine.

It is still on either the original impellor or the first replacement, but the engine gets a maximum of three weeks in salt water before getting pulled out and the whole system fresh water flushed, so you might be onto something there...

I wonder if there's another impellor of similar dimensions (identical, in terms of the tip diameter and blade width) made in another factory, with a decent bond - if the shaft journal were slightly bigger, it would be no major problem to machine it down.

[NoTies]

Out of necessity I have re-bonded 2GM impellors with limited success. It seems to be a major issue with them. Am currently running an impellor for a 12mm shaft instead of the Yanmar standard 3/8" shaft, I bushed it down to suit. It has been in for over a year now & no problem. I assume the greater surface area of the bigger diameter boss is the reason.

[Andrew Troup]

NoTies
Interesting ... do you have a part number for the impeller you used, or can you remember what engine or pump it was intended to fit?

When you say "bushed it down" I'm not sure I understand what you mean

[Badsanta]

Maybe I assume too much. But I understood that the 1gm,2gm and 3gm used most of the same parts. That the water pumps were the same. I bought some aftermarket blue run dry impellers to fit my 3gm30 that worked well. I dont quite understand gluing the impeller blades back on. If they are not holding up. I would concider loss of water (lubrication) or roughness inside the pump and needs rebuild or replacement. I doubt that you got an entire crate of bad impellers. I would look at causes to failure instead of the impeller itself. best of luck tracing it down.

[NoTies]

Badsanta, the problem is the metal driving boss coming away from the flexible impellor.
Andrew, no part number unfortunately but it is a standard Jabsco impellor. Jabsco make these sive impellors with pin drive in both 3/8" and 12mm shafts. I made a bush out of the centre of an old impellor so a 12mm would fit onto a 3/8" shaft. For some reason the Yanmar pumps are 3/8"

[Cruisingscotts]

If you are set on gluing it back together, I recently used west systems 5min epoxy to set some miss ordered EPDM coupling elements into the cast steel coupling halves. This was a 30hp direct drive electric motor. One of the pumps fouled and it actually separated the rubber element with out the west epoxy letting go at the rubber to metal glue joint. So if I was to try a rubber to metal glue process this would be one I would try, cheep too.

[Buzzman]

I'm not sure if this will help, but my old British Seagull outboards use a plastic 'rotor' which is so desinged as to not touch the sides of the water chamber at all. Last forever.

But they don't need all that much water flow....

Might be worth a 'test' if somneone wants to have a go at grinding the 'bulbs' off the ends of the vanes until they 'just don't quite' seal.

Never know, it might work...

[mikedefieslife]

Originally Posted by bill good

I have been changing these impellers every 12 mths & run the engines weekly. The temp warning is very close to normal operating temp which is what will save the engine. This is an on going 1GM problem for salt water by my experence. Maybe plumbing a fresh water wash in the system may also help. I just though someone may have tried to rebond one that failed early in its ops.

Won't the temp sensor for the warning light only work reliably if there is water?

You could if you wanted alway fit a electric pump and be done with it. Just need to get the flow right. I've seen it done of RTW cars/motos. I've even seen a washing machine pump used on a motorcycle as a temp fix.

[Compass790]

If you are worried about the Yanmar price for impellers ( & what 1GM owner wouldn't be !)look for the Jabsco equivalent or another aftermarket impeller supplier. Our YSM8 is raw water cooled & impeller is 5 years old. We do fresh water flush when we return to berth but not sure if that makes any difference to impeller life as a berth neighbour doesn't & his impeller is 10 years old he assured me.
Maybe that model of raw water pump is problematic? In another similar thread someone suggested replacing pump with magnetic drive 12v water pump. I have no experience with that but could be worth looking into