Engine oil smells like gas

[psben81]

Hi Everyone - I have a 1968 Series 2a 109 2.25 petrol and recently noticed the engine oil has a strong gasoline smell when checking the dipstick.

There is an electric fuel pump running inline with the original mechanical fuel pump on the block.

- Is it likely that the diaphragm on the mechanical fuel pump ruptured into the block? Any other source to be leaking fuel into the oil?

- Can i bypass the mechanical fuel pump and just run the electric pump to the carburetor?

I have been debating switching back to a mechanical fuel pump. I appreciate your thoughts.

Thanks for the help! Ben

[mearstrae]

I'd pull the mechanical pump and check the diaphragm. An over-rich condition can also add fuel to the oil, but not as common. But why run a mechanical pump if you have an electric one? That seems to be asking for trouble with the mechanical pump. I'd just remove the mechanical pump and block off the mounting hole and stick to the electric pump at all events. My '70 and '76 have had the mechanical pumps removed and use only an electric pump. You need to attend to this ASAP as the fuel in the oil is washing the lube from all the bearings and cylinder bores.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S

[psben81]

I'd pull the mechanical pump and check the diaphragm. An over-rich condition can also add fuel to the oil, but not as common. But why run a mechanical pump if you have an electric one? That seems to be asking for trouble with the mechanical pump. I'd just remove the mechanical pump and block off the mounting hole and stick to the electric pump at all events. My '70 and '76 have had the mechanical pumps removed and use only an electric pump. You need to attend to this ASAP as the fuel in the oil is washing the lube from all the bearings and cylinder bores.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S

Thanks for the recs!

[SafeAirOne]

But why run a mechanical pump if you have an electric one? That seems to be asking for trouble with the mechanical pump.

109's with rear fuel tanks came from the factory with electric and mechanical fuel pumps in-line. In extreme nose-up attitudes, the fuel tank could be too low for the mechanical fuel pump's suction to draw fuel, so they added an electric boost pump to eliminate this problem.

[psben81]

109's with rear fuel tanks came from the factory with electric and mechanical fuel pumps in-line. In extreme nose-up attitudes, the fuel tank could be too low for the mechanical fuel pump's suction to draw fuel, so they added an electric boost pump to eliminate this problem.

Good to know! thanks