4 stroke idling problem and spark plug black

[clemens3964]

I have tried to start my 2004 8hp high thrust outboard today and it started but wanted to cut out and was very erratic and was misfiring. I took both spark plugs out and they were black even though they have not even done one our of running since service. I cleaned them off and it ran better but there was a black residue coming out of the small exhaust hole which I could only remove with a detergent cleaner, it was like soot. The engine is also vibrating at tick over and only stops when I increase the revs slightly. Is there a potential problem and what could cause it please?

[melaatik]

leaked oil burned in the cylinder?

Has it been stored or transported properly? If the engine has been left on wrong side of it, there can leak motor oil to the cylinder that generates a lot of smoke when first starting. That could also be the black stuff in the exhaust.

I would suspect that unperfect running at idle is causing the vibrations. In this case, try to clean the carb(s).

[clemens3964]

Leaked oil burning

It was serviced whilst still attached to the boat as it was craned ashore. There were a few very bad storms where the boat was buffeted a lot but it is in the same position it has been in for the last 6 years. It does sound from your answer that it isn't much to worry about which sounds good. Thanks for the reply, I will give the carb a clean. Regards Wayne