3 replies to this topic

[Pigeonto]

 Today ! 004.JPG   38.64K   5 downloads

 

There's a little hole at the bottom which is letting OIL out. Not fuel.

It's the original pump so it's 25 years old now.

I reckon it's there to let out any fuel which may pass the diaphragm.

Does anyone know if there is any kind of seal in there, intended to stop engine oil reaching the hole which may have given up ?

This is a fresh build and it's not 'breathing' ; ie no crankcase compression.

Could it be blocked off? I realise fuel would then get to the engine if the diaphragm split but I don't believe it's large enough to work anyway.

Damned annoying as it's the only leak on the engine....Yes you read that right !! lol

 

 

[Spider]

The hole is there mainly as a breather that allows air in and out as the pump pumps. There's the diaphragm seal within that flexes to pump the fuel and between that and the crankcase is an Oil Seal. The hole is there to vent this space between these two seals.

 

Blocking it off wouldn't be wise as it will cause a failure of the Oil Seal that will let Oil in to the back of the Diaphragm, that in turn will rot the Diaphragm and then let Petrol in to the Sump, so you'll find your Oil Level rising!

 

The other purpose of this hole is a tell-tale to let you know that the Oil Seal has failed and that the Diaphragm will also soon fail.

 

Best to replace the pump.

[Pigeonto]

Ah, right. So there is a seal which has failed. I was concerned there may be something more sinister causing it.  I'll renew the pump. This one has the 5/16" inlet tail and 1/4" outlet which I didn't think is available now but it is so no problem. Thank you for that

[whistler]

Had the same with mine last year. Oil all down back of engine and on top of diff case. Came from same orifice as yours. Nothing to do but chuck and replace. I changed mine back to a rear subframe electric pump so I could isolate it as a security measure. Also means I can drain the tank through the electric pump if I need to.