Leaking Impeller

[Lambada30]

Hi All,

I've just purchased a new boat (really excited!). The main thing I need to fix is the raw water impeller. It seems to be leaking (visible from the salt build up). The last owner said he replaced the impeller 12 months ago including a new paper gasket. The engine is a 16hp YANMAR 2GM20C. Would you recommend doing anything special when I replace the impeller and gasket again to stop this leaking?

There's also some corrosion/water marking on the engine from a leaking anode plug. Any ideas how to to clean this up?

I've attached some photos.

Appreciate your help!

[JimsCAL]

It's not the impeller that's leaking. Could be either the gasket or the shaft seal. I can't tell what you are pointing to in the first pic, but the rust stain in the second pic is nowhere near the pump. Looks to be the exhaust connection. The pump will be on the front of the engine.

[Bill O]

Agree you have 2 leaks to deal with but probably not too bad.

The water pump">raw water pump is either corroded badly and the gasket isn't sealing or you need to do a full rebuild on the pump. If it is corroded badly, replacing the pump would be good, as eventually it will need to be done if the surfaces are too corroded.

The exhaust leak looks minor, but persistent. Shouldn't be too bad to fix. Repainting the area may be more of a pain than the actual fix.


Bill O.

[gonesail]

i am thinking you should install a new impeller pump. and they are not cheap. not sure about your other problem.

[a64pilot]

Once you get the leaks stopped, buy some rust stop and a SS toothbrush, clean off most of the rust leaving just a little, threat to with the rust stop, and buy some Yanmar spray paint. Don’t try spraying it, you’ll make a mess, spray it into a small bottle like a baby food bottle and then brush it on with a detail brush.
It will match perfectly.
Don’t let any rust accumulate on your engine, ever. It does nothing good and is just too easy to get rid of.

[Lambada30]

Thank you for your advice everyone! The boat has a new gasket in its spares kit. I might try cleaning up the pump and putting that on it to see if it stops the leaking?

I don't think my photo was too clear but it looks like the leak was coming from the anode plug. Where on the exhaust do you think its coming from and how would you fix it?

Thanks for the suggestions on how to clean up the rust.....it does seem to be a bit of a job to clean up the mess!

[Suijin]

Just to expand on a64’s advice: new paint is not just cosmetic, and not just to stop rust. It makes it much much easier to spot leaks in future when they are still minor.

[Wotname]

Pull the exhaust mixing bend and check it carefully for both blockage and rusting though. Pull the anode and replace if necessary. It will become obvious where that leak is occurring. The exhaust should be pulled regularly (every couple of hundred hours) - they block up!

Pull the raw water pump and completely rebuild (new seals, bearing, impeller etc). The bearings and seals are available at any half decent bearing supply shop in Oz and not expensive. The shaft of the pump may be worn and if so, that will take a bit more work to sort out but if it is, get back to CF for more help .

These bronze pumps are usually repairable for decades.

[Wotname]

Regarding the anode on that engine, I usually remove the fuel pump for access rather than removing the fuel line, saves bleeding the fuel system. If you haven't had the fuel pump off before, get a new gasket before starting the job! Same with the exhaust bend.