diesel fuel leaking into engine oil, JD450b

[rbp]

I was told today to get rid of mechanical lift pump cause the rubber diaphrams are cheap and cause leakage into engine oil. This guy told me to completely take the lift pump off and cover up hole and use electric lift pump. I had left the old pump in place and he thinks that diesel was still going through it and into the engine oil.

[boaterri]

Umbrella seal in the injector pump could be leaking.

[B Town]

If the internal components of the lift pump have failed and allowed fuel to leak into the oil sump(which is a fairly common failure) you either replace it or completely bypass it. If you still have fuel running through it, the fuel will continue to leak into the oil. Have you isolated the pump and tested it to see if it is the failure point??

Umbrella seals inside the injection pump are another area of concern.

[Jim B]

Have you removed the fuel lines from the mechanical transfer pump? If the lines are off it, it can't put fuel in the base. If the active fuel lines are still on it, the pump would be my first place to suspect a leak into the base.

If the lines are off the transfer pump,the umbrella seals on the injection pump drive shaft are likely the fuel leak into the base.

Personally, I haven't had problems enough with the mechanical.pumps to make me want to install an electric pump. Each to his own.