Leaking impellor casing

[mireland]

I have a Bukh 36. Replacd the impellor and found it really hard to fit the new gasket mainly because of the location and having to do it one handed. Surprise surprise there is now a small leak. I estimate a couple of litres a day. Can I safely run the engine and defer doing it again for a week or two? I know nowt about these things.

 

[Phoenix of Hamble]

I give this response recognising that I am happy to bow to the superior wisdom of many on this forum!

My initial reaction would be that if the casing is leaking at static, then when the engine is started and the impellor puts the system under pressure, the leak can only get worse..... I would personally go through the hassle of fixing it.... you don't want to find out that its a problem when you NEED the engine.....

 

[VicS]

That assumes the leak is on the pressurised part of the system.

I would check it running and non running making sure that there is a normal water flow when running. If all appears well then perhaps no panic necessary but it would still be prudent to sort it out as soon as reasonably practical and certainly before any long voyage.

Make sure you know where the leak is from before fixing as you may have disturbed/damaged the shaft seal in which case you'll have to replace that.

 

[Colvic Watson]

Same just happened when I replaced the impeller on my Yanmar, ripped the gasket and there was a slow drip when the engine was stopped - then a great spray of water when over 40% revs! I know they're tricky to replace but I'm not sure there is any alternative, cost me another £2.50 for a new paper seal and another half hour with my head in the engine.

 

[VicS]

I'm not familiar with this engine but it might help reassembly if you stick the gasket in place with a smear of grease. Perhaps you can stick it on the cover and put a couple of bolts through then offer it up. That way the bolts will help to keep the gasket in position, screw those in partway then put in the remaining bolts loosely mark sure everything is ok then tighten progressively.

As I said I'm not familiar with this one but I'm sure adapting the above to suit should help.

 

[Aja]

Dont know which type of Yanmr - but on the 2 and 3 GMs its much easier to remove the whole pump assembly. a smear of grease on the face cover and then place the gasget onto the pump.

Would really hate to do that at sea.

In response to Mireland. Is the water coming out between the pump and the cover plate? Check that the cover plate is not worn. Reversing the cover plate is a get home fix where this is the case.

Donald

 

[30boat]

I came up with a simpler and also one handed way .
First I clean the plate,then I cover it with white masking tape(Tesa) taking care not to overlap the sides or leaving any gaps.With an X-Acto knife I then cut out the inside following the marks left by the old gasket.The tape is translucent enough for that.Never got a leak and it's very easy to remove and redo when necessary.
You can put some vaseline on it but never grease as the impeller doesn't like it and might break up.Cheap too.

 

[Piers]

Don't defer - refit it asap.

When fitting the impellor, its gasket & cover, grease the impellor shaft, the housing interior, and the inside of the cover plate with silicon grease. This grease will not damage the impellor in any way at all, and ensures plenty of lubricant when first starting.

The silicon grease will also hold the gasket in place whislt you refit the cover plate.

Take care not to overtighten the cover plate nuts and strip the threads. Just tight enough to prevent leakage.