Hello

For a while now the head (or the engine entirely) jerks a lot when I move of
into gear. Everything is fine at idle (+/- 800 RPM) but when I put it into
gear forward the head jerks mainly between 1000 and 1800 RPM. Please note
that my 1999 Mariner 115HP runs on only 2 cylinder below 1800RPM.

What could possibly cause that jerking, too much oil ? too much gas in th
cylinders ????

Thanks