Why has my sump filled with petrol???

[davewhitefoot]

Having dipped the sump I found it full of petrol (plus oil). My best guess of the cause is that valves are not closing properly . Any other ideas?

[RobH]

Leakage from the mechanical fuel pump. Possibly a split diaphragm. The pump cavity is open directly to the sump. 

I can't see any way this could be related to valve operation. 

 

 

Edited August 25, 2023 by RobH

[Lebro]

+1

Bob

[Z320]

Sadly, like Rob and Bob, also in my opinion a split diaphragm is the only reason for this, 

and sadly inside the pump the push rod seal is missing.

With this fitted the petrol should drain out of the small hole below the diaphragm.

Ciao, Marco

Edited August 25, 2023 by Z320

[davewhitefoot]

Thanks guys. As it happens, before I noticed the sump full of petrol I found that petrol delivery to the carbs was intermittent at best and so I have purchased a new petrol pump. I haave been away since then and so, when I have fitted a new oil filter and refilled the sump with new oil I can check out if the problem has gone away.