VP 2020 not so smooth

[homer]

When I bought the boat, it was a year old and the Volvo 2020 ran very smoothly; at low/moderate revs you would hardly be aware of it. Two years on and it is not so smooth (although no worse than many others I know!). This applies in neutral as well as in gear and so, presumably, has nothing to do with the prop/shaft. It has been suggested that the engine mounts are deteriorating although there is nothing obviously amiss with them. Just wondering if anyone can think of any other possible cause?

 

[tillergirl]

I have a 2030 and last year replaced rear engine mounts following engine removal to do the keel bolts. Point 1 was that one mount had given way and was held together by the weight of the engine and its shape. Could not see anything wrong and you could not tell anything was wrong until the engine was lifted and the top half of the mount could be lifted separately. Point 2 was that on enquiry it seems that failure was not unexpected after 10 years (15 for the front curiously - less weight?). You are nowhere near that in age of course. Point 3 I wish I replaced the front at the same time because it doesn't seem as smooth when running as before but like you its no worse than others and indeed much better than many. None of which helps really!

 

[Topcat47]

I replced my MD1 with a Yanmar so I can't comment on the mountings of the 2020. However, the mountings on the MD1 were replaced by me one winter and two of the four failed within weeks (I replaced them). When I removed the engine for overhaul three years later, only one mounting was secure, the others fell apart when I tried to remove them.

I replaced the engine with a Yanmar chiefly due to the cost of the spares to recondition the MD1b and the poor reliability of the mountings and the coupling rubbers.

Failure of the engine mountings, even only one, will result in lumpy running, and a knackered cutlass bearing; possibly even the shaft seal.

Replace them all if you have to replace any. My experience with the Volvo mountings would lend me to have a professional do the job, not because I can't but because if anything failed, they'd have to rectify the job, including the replacement parts and a lift out, if it was needed.

Oh yes and check them every winter, or at least every haul out if you don't winter ashore.

 

[Trevor_swfyc]

The engine should not have a detectable loss of smoothness in that time scale, have you changed something?. Maybe it's as simple as a slight amount of air in the diesel filter, or even a slight air ingress somewhere on the diesel downstream from the pump. Injectors can cause poor balance if one of them is not giving good atomization, they are easily removed and can be checked usually for free.

Trevor
Mines a Volvo 2002