hello..i have to overhaul prelubricating pump for a wartsila 4WL20 generator and i'm not sure that it can be done without emptying the sump and collecting lube oil in drums or it can be done without emptying the sump..any help

I must be able to be done.

Picture?
Line diagram?
It's a pre-lube so it's +ve disp, so it's probably is above the oil level and draws the oil up...

I'm sure it's fine.
Fate fortunes the bold?
God hates a coward?
Do it.

yup..removed prelub pump..pump was below sump level thats why was getting doubt but found out that there is non return flap to prevent system oil from draining..thanks for input though..cheers

Both suction and discharge lines were below the sump level, and there was a flap check to stop oil drainage...
Interesting.

Hmmm?