Which sealant for a gasket?Yanmar 2GM20 Water pump

[crown22]

Hello
I am just about to replace my impellor and gasket. Can anybody say which (if any) sealant they use on the gasket?
Thanks

 

[Poignard]

I wouldn't use any.

 

[Boater Sam]

Traditionally just grease so that it beds in and is waterproof. But a smear of Blue Hylomar would do no harm.

 

[Daydream believer]

I use a bluish/transparent gasket compound that dries to a rubbery consistency. Forget the name, comes in a tube!
I place it on the cover & then insert 3-4 short pieces of smallest cable tie into the compound so that they stick out.
I then screw the cover down ( this keeps it to a parallel 1.5mm thickness) & leave it for a few hours until the compound starts to get a rubbery feel. I then slide the pieces of cable tie out & screw down , but not over tight. I got fed up with the supplied paper gaskets leaking. This works for me

 

[Neeves]

I use a bluish/transparent gasket compound that dries to a rubbery consistency. Forget the name, comes in a tube!
I place it on the cover & then insert 3-4 short pieces of smallest cable tie into the compound so that they stick out.
I then screw the cover down ( this keeps it to a parallel 1.5mm thickness) & leave it for a few hours until the compound starts to get a rubbery feel. I then slide the pieces of cable tie out & screw down , but not over tight. I got fed up with the supplied paper gaskets leaking. This works for me

I do something similar, if not identical. I've used a red coloured and a grey coloured one - from a tube. A tube would last a lifetime - but it can go hard (in the tube). I don't open the seacock for 24 hours (or as long as possible), to ensure the gasket has at least skinned. Whether this is necessary - I don't know. You can buy a liquid gasket material in any 'auto parts' retail outlet, I guess like Halfords. It messy stuff - I use turps as a cleaner.

When you take the cover plate off the pump have a clean tin can handy into which you can drop the tiny bolts that hold the plate to the housing - you don't want to lose any! If you plan ahead - buy a few spares bolts. I changed all of ours for recessed Alan key heads as being easier to work with on our confined engine bay.

Normally I would service the water pump with the rest of the engine. I complete the water pump first and then check everything else as nothing else might be time dependent. I'd also try to leave myself 24 hours before I run the engine with the seacock open. We have a cat with 2 engines and servicing both and cleaning up is a day's job - so leaving for 24 hours is part of the process.

Jonathan

 

[UK-WOOZY]

shouldnt need to use any sealant, just the gasket and some lubricant that comes with the service kit

(my engine is a Yanmar 2GM20 raw water)

 

[Daydream believer]

shouldnt need to use any sealant, just the gasket and some lubricant that comes with the service kit

(my engine is a Yanmar 2GM20 raw water)

"shouldn't" being the operative word. But if it does, what do you do then? Mine always leaks even with a paper gasket & a new cover plate & all surfaces properly cleaned. There is only so much torque one can apply to a 5mm bolt

 

[Poignard]

"shouldn't" being the operative word. But if it does, what do you do then? Mine always leaks even with a paper gasket & a new cover plate & all surfaces properly cleaned. There is only so much torque one can apply to a 5mm bolt

The only reason I can think of for yours leaking is that the mating surfaces of the pump body is not flat. (You say you have tried a new cover plate.)

(I'm assuming that your pump is similar in design to the Johnson impeller pump fitted to my BUKH engine; which has never leaked during my 25 years ownership, and never has any gasket cement on it.)

There's no harm in using a sealant, provided it doesn't get squeezed into the pump chamber, but I like to be able to change the impeller quickly if I need to without wasting what might be precious minutes scraping off old, hardened gasket cement and finding a tube of new cement.

 

[UK-WOOZY]

the pump on my 2gm20 is newish, about 2 years ago i got a new pump as the inside of the old pump was warped/worn and not priming properly, but it didnt leak at all, neither does the new one, so must be worn/corroded surfaces of your pumps

 

[Daydream believer]

the pump on my 2gm20 is newish, about 2 years ago i got a new pump as the inside of the old pump was warped/worn and not priming properly, but it didnt leak at all, neither does the new one, so must be worn/corroded surfaces of your pumps

I am on my second pump & both have leaked
If I had to change the impeller in an emergency I would not worry about a bit of a leak The compound I use just peels off with a sharp knife so would not be an issue. But if others have pumps that do not leak , great. I only offered a solution to some drips

 

[ghostlymoron]

I always use just the paper gasket and supplied grease. Anything thicker may reduce the efficiency of the pump.

 

[Poignard]

I am on my second pump & both have leaked
[...]

Looking at the high price of replacement pumps, your bad luck is expensive.

 

[V1701]

I'd recommend delta D510 anaerobic multigasket, I use it for the boat and motorbike. It only cures in the absence of air, any that finds it's way inside dissolves in the oil/fuel/water, any excess on the outside wipe it off...

 

[Daydream believer]

Looking at the high price of replacement pumps, your bad luck is expensive.

Having replaced the shaft on the first one I felt that there were issues that required a new pump. I forget the exact details, as it was some time ago.

 

[Bilgediver]

"shouldn't" being the operative word. But if it does, what do you do then? Mine always leaks even with a paper gasket & a new cover plate & all surfaces properly cleaned. There is only so much torque one can apply to a 5mm bolt

Sounds like at some time there has been a little bit of overtorquing that distorted the flanges. A smear of grease on both sides of the gasket which is cut from chart paper does fine for me.

 

[Daydream believer]

Sounds like at some time there has been a little bit of overtorquing that distorted the flanges. A smear of grease on both sides of the gasket which is cut from chart paper does fine for me.

Do you really think that one can "over torque" slotted brass screws that are fitted to the johnson pump? Plus bend the cover plate to allow the flange to lift in the process. I would suggest not. Besides the replacement leaked from day 1 . The one fitted originally leaked after the first couple of impellers. I had to replace several in the first couple of years, I had the boat from new

 

[Poignard]

If I bought a pump that leaked from day 1, I would expect the supplier to be sending me another on day 2.

 

[Neeves]

If I bought a pump that leaked from day 1, I would expect the supplier to be sending me another on day 2.

This is the marine industry where ......


A short story

Our catamaran was the 'show' boat for our builder. Things dropped behind schedule the the commissioning of the 2 engines was conducted by the engine manufacturer as the cat was motored to the show. The engine configuration and all the components had been approved by the engine manufacturer. During the commissioning run the engine rep noted that there was a noise and this should be investigated at the first service (demanded, for warranty, at 50 hours). However it might be an injector and the problem, might solve itself. At the 50 hour service the approved service agent said he was not able to identify the cause of the noise and when we arrived back in Sydney 500nm away we should have the noise checked.

Frankly I did not know what they were talking about - I was unable to detect the noise to which they referred.

In Sydney the appointed agent said the engine would need to be removed.

Engine was duly removed.

The fault was a bent con rod. I saw the con rod - it was definitely bent.

I was told as this was my fault I would need to pay for the engine removal, new con rod and replacement of the engine.

I did not hold back, violence was not used, but threats of taking the engine supplier to court did work wonders - and the engine was duly replaced at 'someone' else's cost.

Any you think the water pump would be replaced without question in 2 days.


Dreams are free.

I recently changed the impeller on the same engine. I took the old impeller out and it was perfect. However as I was going to change everything else, fresh filters, fresh oils etc I decided to replace the impeller anyway and keep the, good, old one - in case. Our engine bay is tiny and access to the seawater pump difficult. I did have a genuine Johnson impeller - it came in a Johnson box - with strict instructions to use a genuine part on a Johnson pump. I spent 30 minutes trying to fit the Johnson impeller. No success. I gave up and replaced the impeller, in a few seconds, using the old one.

The 2 impellers were indentical except that the Johnson version was made from more stiff, less flexible rubber. I don't know if the one I took out was more flexible because of use or simply because it was made from a 'different' polymer. The old one works fine. In order to install the impeller I need to do so by feel, I cannot see the end of the slotted shaft (as I am not a monkey). I sit on the inside of the hull, knees up at my head and use one hand under my knees to force the impeller into the housing. The new less flexible impeller was difficult to manoeuvre inside the housing in order to align the pin in the impeller and the slot in the shaft. When I turned the impeller in the housing the shaft turned at the same time. The old impeller was an original part from the engine manufacturer.

If I could have eye balled the impeller and housing I could have aligned the various items (which I can do on the other engine). I'll use the Johnson on the other pump and use the engine manufacturer's impeller on the more restricted space engine.

The joys of boat ownership.

Jonathan

 

[Poignard]

I don't know how things are in Australia but here in the UK we have effective consumer protection laws.

If I buy a product and it is defective I contact the supplier and ask for a replacement to be sent. And I expect to get it as quickly as is reasonably possible (or my money back).

Nowadays, reputable suppliers of goods know what their obligations are and have no problem in complying with them. They want to keep customers happy and maintain a reputation for good service.

That is as it should be.

 

[ghostlymoron]

The only problem I've had with boat parts is the initial price. On the rare occasions when I've needed to replace them, they've been swapped with no problems. I find it's always best to stay calm and assume the supplier will swap it, which they always have. Assume it was a genuine mistake and avoid losing temper or shouting.