Leaking impeller seal on 1GM10

[DoughMyDays]

My impeller seal has begun to leak. Whilst I had it open, I thought i might aswell also replace the impeller as its not been done for a couple of years and also replaced the seal for it.

No matter what i do, even with the new seal, it still leaks slightly from the bottom. I have cleaned up the old gunk from the previous seal and done my best to make sure its clean.

Anyone else had this issue?

It is this part I am referring to

 

[earlybird]

A paper gasket? Are you really sure the surfaces and gasket are clean and undamaged? The screws on these pumpsneed to be fairly tight. If light greasing does not help, a non-setting sealant such as Hylomar might do the trick.
Or try a home-made gasket from slightly thicker material, eg thin cardboard.

 

[DoughMyDays]

A paper gasket? Are you really sure the surfaces and gasket are clean and undamaged? The screws on these pumpsneed to be fairly tight. If light greasing does not help, a non-setting sealant such as Hylomar might do the trick.
Or try a home-made gasket from slightly thicker material, eg thin cardboard.

I will check again when i go next to be sure. Yes it's a paper sealed gasket one. I make rubber and tpu mouldings for a living so may try that. I have cloned the paper seal from thicker material but yet to try this.

 

[NormanS]

I will check again when i go next to be sure. Yes it's a paper sealed gasket one. I make rubber and tpu mouldings for a living so may try that. I have cloned the paper seal from thicker material but yet to try this.

Mine's a different pump, but is made from Corn Flakes packet smeared with Coppaslip. Other cereals and greases are available.

 

[Pye_End]

Is the face plate worn? Sometimes you can reverse them.

Bit of 1000 grit on something flat will help to see if there is any distortion on the pump face.

Sure the leak is from the front and not the tell tale behind?

Check and protect the oil pipes underneath!

 

[Spirit (of Glenans)]

Too thick a gasket will introduce a gap between the cover plate and the front face of the impeller, thus reducing its efficiency.
My money is on Pye Ends's suggestion that the seal on the shaft is worn. Should that be the case, a search of this forum will give you info on how to replace it. You can change the water seal without necessarily having to change the oil seal. The seal itself will cost between 5 and 10 pounds.

 

[NormanS]

I'm not familiar with the particular pump, but it shouldn't be too difficult to tell where the leak is coming from. One end is the faceplate, and the other end is the shaft seal. The bad news if it's the seal end, is that the seal tends to wear a groove in the shaft - so much so that if the shaft is damaged, a new seal won't solve the problem.

 

[Tranona]

Unlikely to be leaking from the cover plate gasket unless the face plate is worn. Much more likely to be the shaft seal which needs fixing quickly or you will find seawater dripping on the timing case cover and the oil transfer pipe causing corrosion. Thickness of gasket is important - only use the Yanmar paper one as anything thicker will reduce pumping efficiency.

 

[Spirit (of Glenans)]

I'm not familiar with the particular pump, but it shouldn't be too difficult to tell where the leak is coming from. One end is the faceplate, and the other end is the shaft seal. The bad news if it's the seal end, is that the seal tends to wear a groove in the shaft - so much so that if the shaft is damaged, a new seal won't solve the problem.

There is a product available, of which I cannot just now rember the name, (perhaps microfoil), which can be slid onto the shaft, to cover the groove, thus restoring its integrity.

 

[Tranona]

There is a product available, of which I cannot just now rember the name, (perhaps microfoil), which can be slid onto the shaft, to cover the groove, thus restoring its integrity.

SKF Speedi sleeves - useful for saildrive propshafts which are expensive, but probably not worth it for the Yanmar water pump shaft which is (relatively) cheap.

 

[andsarkit]

If the leak is from the hole at the bottom and you have already replaced the seal, it could be wear or pitting on the shaft.
You can get new shafts in 316 or super duplex from here : FFS Systems. The super duplex will be better than the original and probably cheaper than the Yanmar part.
You can also contact him as dinghyman of this parish.
New pumps are a silly price in UK but if you have contacts in USA they can be obtained for half the UK price.

 

[Sailing steve]

You can salvage a worn GM1 shaft and stop the leak with new seals and inserting a thin packing piece - I used a 2.0mm thick fibre tap washer - in the seal housing before you fit them.

The seal is displaced by the washer and it's lips then run on an unworn position on the shaft which is effectively the same as buying a new one. Three years in and mine hasn't leaked a drop.