Mercury QSD problem

[Gustav]

I have a two and a half year old Mercury QSD 220hp 2.8L

Observed blue smoke from exhaust and smelt unburnt fuel. Pulled the injectors out and got them tested on my local engineers trigger box. Injector 3 pressured to 200bar and the other three tested to 300bar. We pulled the cylinder heads off and found that cylinder 3 had a worn valve and valve guide. So sent all 4 cyl heads and injectors to the specialist for a proper diagnosis. All 4 Injectors tested to +/- 1500bar and they all passed. The cylinder head valve guides were inspected and found to be excessively worn, one guide was severely worn which led to valve damage and blowby which made me aware of the problem.

Told this information to Barrus and they believe it’s the fuel I am using.. I purchased the boat from a friend who had it meticulously maintained and fully serviced. He was in a different marina to me where they used Ultra low sulphur (ULS) red diesel where as my local marina has MGO (marine gas oil). The boat had a full tank off fuel (ULS) when purchased and I have only done 50hrs before this occurred. In a nutshell the boat has been ran for 40hrs on diluted fuel ULS & MGO. I do not buy what Barrus says saying it’s the fuel? How can the valves and guides fail at so little hours on diluted fuel??? No one else has had any issues using the local fuel.

Has anyone got any Idea’s to what the problem may be?


Thanks

Angus

 

[rafiki_]

Bump. As a new poster, your post gets delayed, so I have bumped it up so our engine experts, VolvoPaul and Latestarter1 can see this. Our Mercruiser expert is Tom Parker of Tompa Marine. You might try googling him and giving him a call.

 

[volvopaul]

I have a two and a half year old Mercury QSD 220hp 2.8L

Observed blue smoke from exhaust and smelt unburnt fuel. Pulled the injectors out and got them tested on my local engineers trigger box. Injector 3 pressured to 200bar and the other three tested to 300bar. We pulled the cylinder heads off and found that cylinder 3 had a worn valve and valve guide. So sent all 4 cyl heads and injectors to the specialist for a proper diagnosis. All 4 Injectors tested to +/- 1500bar and they all passed. The cylinder head valve guides were inspected and found to be excessively worn, one guide was severely worn which led to valve damage and blowby which made me aware of the problem.

Told this information to Barrus and they believe it’s the fuel I am using.. I purchased the boat from a friend who had it meticulously maintained and fully serviced. He was in a different marina to me where they used Ultra low sulphur (ULS) red diesel where as my local marina has MGO (marine gas oil). The boat had a full tank off fuel (ULS) when purchased and I have only done 50hrs before this occurred. In a nutshell the boat has been ran for 40hrs on diluted fuel ULS & MGO. I do not buy what Barrus says saying it’s the fuel? How can the valves and guides fail at so little hours on diluted fuel??? No one else has had any issues using the local fuel.

Has anyone got any Idea’s to what the problem may be?


Thanks

Angus

I wouldn't believe what Barrus say, this sounds like an engine installation problem to me, worn out parts at such low hours isn't right, what boat is it in?
I'd make one assumption that there is an issue with its installation on the exhaust side, it's either too small a diameter not allowing the gasses to escape , badly routed or a wrong silencer fitted causing to high exhaust gas temperature, before you spend and rebuild it I'd be checking the back pressure and temp when it's flat out under load .
As per ther fuel theory therevengines are designed to run anywhere not just here , other parts of the world have far worse spec fuel than we do, the only other thing is water in the fuel but I'd say you would have known before then unless you have no water in fuel monitor .

 

[Gustav]

The engine has only covered 550hrs and it sits in a Arvor. No water in the fuel, and the silencer is fitted by the manufacturer. I am possibly thinking it might be poor quality material in the valve guides? The boat is fitted with smartcraft gauges so I would have thought the issue might have been displayed but nothing.

 

[Bouba]

I do remember there was a lot of talk on the Arvor Owners forum about problems with the QSD in the Arvor 25. It was the black engine as I recall? The QSD 4.2 in the Arvor 280 had a better reputation. It will be worth your while researching this as there is a large knowledge base on their forum.