Mercruiser 5.0 MPI. Help, please!

[geufx]

We have a boat equipped by two Mercruiser 5.0 MPI engines. Both have the same problem: incoming fuel onto oil. After a short time oil level rise due to fuel incoming. Fuel pressure in the rail is normal.
Computer diagnostics: all OK! Injectors have been checked and cleaned. We have no idea what to do the next. Help, please! Any assistance will be greatly appreciated!

 

[rafiki_]

Welcome to the forum.

It sounds like you need Tom Parker aka Mercuryman of www.tompamarine.co.uk

 

[QBhoy]

Hi
Off the top of my head....
Mechanical pump passing past engine driven seal ?
Have you checked there compression ? Does she perform well ? Perhaps in burnt fuel passing down past piston rings at idle ?
Good luck ?

 

[QBhoy]

Excuse spelling ! Bloody IPhone and fat fingers....should be "unburnt" and "Their"...haha.
Do you spend a lot of time with the engines idling ? Perhaps charging batteries at the mooring ? This can cause the above problem.

 

[QBhoy]

Just another thought...do the electric fuel pumps (when you turn ignition on) cut out after a few seconds, as they should, or do they cut in and out ?

 

[geufx]

Thank you very much for your attention, dear friends!
1. We have no mechanical fuel pump at all.
2. Electrical one is working properly: starts and cut out in time. Fuel pressure is normal.
3. We have not used engines idle for a long time, and do not need to charge batteries, the boat is connecting to shore.
Have you any more ideas?
I'll try to ask Tom Parker too, of course

 

[gordmac]

The only way fuel will get in to the oil is from the injectors past the piston rings. Over fueling, cold enrichment not going off? That would be a faulty temperature sender I would think, worth checking.