Volvo Penta MD2010 loss of power & black smoke

[jbm1967]

Hi All, I hope someone can help. I did not manage to get down over winter so the engine has not been started for 6 months. Tried to start today and was very difficult to start. It has now started but won’t rev over 2,800 in neutral (usually 3,500) and not over 2,000 in gear (usual 3,000 plus). Lots of black smoke at high revs and black deposit on water. I thought it was the exhaust elbow (was partially blocked) so changed for a new one I had on board. Slight improvement but nothing major. She now starts first time and seems fine at low revs. There is also a slight ticking at higher revs. Any ideas? Thanks

 

[jbm1967]

I have cracked the injector nuts on both cylinders. It has an equal effect so does not seem related to one cylinder.

 

[penfold]

Has a mouse taken up residence in the air filter?

 

[duncan99210]

Check the exhaust hose hasn’t delaminated and partially collapsed, blocking the exhaust. It does sound like an exhaust problem but you’ve eliminated the most likely cause by replacing the elbow, so checking the hose is the next step.

 

[jbm1967]

Has a mouse taken up residence in the air filter?

Your buddy (danger mouse) is nowhere to be seen in the air filter.

 

[jbm1967]

Check the exhaust hose hasn’t delaminated and partially collapsed, blocking the exhaust. It does sound like an exhaust problem but you’ve eliminated the most likely cause by replacing the elbow, so checking the hose is the next step.

I was positive replacing the elbow would sort it. Is exactly the same symptoms. So makes sense. Will have a look.

 

[jbm1967]

I was positive replacing the elbow would sort it. Is exactly the same symptoms. So makes sense. Will have a look.

Hopefully found the problem. Exhaust outlet on engine side was blocked. See pics for better idea of before and after. At low water rn so can’t test until this afternoon

 

[penfold]

That'll do it!

 

[jbm1967]

Certainly did. Running as good as ever! Was working the opposite side to the port so didn’t see it after I removed the elbow.