I took my 1980 Merc 200 out this weekend and it just died. This was the
first trip of the year and I had a little old gas left in the tank. I
filled up with new gas, oil and fuel stabilizer. The engine ran great
the first night and then started running ruff in thr morning. It was
smoking more than usual at idle and then started sputtering and loosing
power at speed. My Tach went out first and then it just died. The
engine will turn over but it is tougher than usual with no positive
combustion. When I pulled the engine out of the water I had oil coming
out of the lower end.
I was lazy and have not replace the impeller sence last Jun.

I am not a great mechanic. Any recomendations on where to start? My
shop is backed up for over a month and I can't wait.
thanks