I Noticed this weekend that I could not rev the engine above 2400rpm beyond which is just produced lots of black smoke. Starts OK, runs at 2000rpm apparently fine, idles OK and temperature normal. Had the injectors re-adjusted about 6 years ago. Engine service annually by myself has done less than 800 hours in 10 years.
Have you tried to rev it that high before? Was this in or out of gear?
If this was in gear, my first thought is something round the prop, however if this is the first time you tried to rev it that high, it might just be that it is overpropped.
Black smoke is an indication of over fueling and will occur if anything holds the engine revs down whilst the injector pump is delivering fuel to rev the engine up – hence my thought that its something round the prop.
It could be that someone has overtightened the stern gland, but it would get very hot if it had been.
If it does it out of gear I would hate to give an opinion, if you have not taken steps to ensure no water gets in with the fuel and into the injector pump/injectors there could be internal corrosion, but that’s a long shot. A starter jammed in mesh and with a seized free wheel could cause this problem when out of gear, but I would have expected some kind of bang and a refusal to start.
I still favour a fouled prop, if its not that, and it is a totally new fault, I think you need to get an engineer to look at it.
