MD5a oilslick

[malcolmpaxman]

I have a MD5A that delivers an oilslick from the exhaust at maximum revs. At all other engine speeds its fine. The lift pump has been replaced and seals on the injector pump replaced. Injector is fine as well.The engine starts ok even in the cold so I doubt rings are in to poor a state. Anyone any ideas. I cannot keep going back to my engine repairer who keeps charging me £500 just to look at it!!!

 

[alb40]

Nothing wrong with it probably.

Maybe its slightly over propped, but its easier just to lay off a few revs to stop it.

 

[VicS]

I agree with alb40. Don't run at max revs except when necessary, stick to 75 to 80% of that. If it is a bit overpropped that's probably better than being underpropped.

I assume this is fuel oil you are talking about rather than lube oil although I can't see how the pump seals or the lift pump would have any relevance, been taken for a ride there? The sump is not overfilled though is it?

The injector spray pattern could be a cause but you say it is OK. Anyway it can't be that bad or you would be making black smoke. (Theses old Volvos are a bit smokey anyway). Air cleaner OK?

If it starts easily, runs OK, does not consume excessive quantities of lube oil, does not make black smoke then I'd say it ain't broke so don't try to fix it!

The commonest problem seems to be overheating caused by clogged up water passages, at least if raw water cooled.

BTW welcome to the forums.

 

[Superflid]

I've got an MD17C and wouldn't like to think of it being run at full revs for any length of time. Nothing wrong with it, but it's an aged lump and it's earned a gentle run into retirement!

 

[starboard]

I have a 26 year old MD5b. It runs as sweet as a sowing machine providing you treat it with respect.......Increase the rev slowly to cruise around 5kts. If you give it full power your speed will not increase but the engine will throw out a slick of unburnt fuel and carbon from the exhaust. This is normal with the engine and is basically the extra fuel the pump has injected that the engine has not been able to burn due to the load on the engine. If you try it in nuetral at full revs you will probablly not have the problem.

Paul.