It’s all running a bit rough
QMy 13-year-old Perkins Perama M30 three-cylinder diesel starts fine, but has begun to sound rough at around 1,600rpm, and very rough at 2,000rpm. Between 1,900 and 2,000 the exhaust takes a very harsh note and makes a ‘pop pop’ sound, with black smoke emitted. At 2,200rpm and above it runs fine. At no load the vibration is subdued to some degree.
It seems to be getting worse. The fitter at our local boatyard suggested that unless the problem was fixed, the engine mountings had a limited life. Any ideas? SIMON BILLIS, via email
ATONY REPLIES: This sounds very much like a misfire, and I suspect the injectors need a good service. If you feel confident to take them out, find a local company that services them for the transport trade – look in the Yellow Pages, go online, or ask a garage. I rather suspect that a needle is sticking. At the same time, check the valve clearances.
If that doesn’t cure it, get the injector pump checked in the same way, but that will require timing and it is not for the inexperienced.