Written on: 02/08/2011 by johnfjmalone (7 reviews written)
We bought this early 1980's motor a couple of years ago from a dealer in Edinburgh.
It ran ok, but not well, which surprised us since it had supposedly just been serviced.
I stripped down the carb, blew out all the jets, reset the float height (which was letting fuel free flow), replaced the incorrect odd spark plugs with two the same in NGK, but would have preferred to get Champions as they are superior plugs imho.
Next, I found out by accident, that our dear petroluem suppliers in the uk, put 10% OR MORE ALCHOHOL in our petrol. In marine circles that is bad news because it absorbs water - which I found in my fuel filter.
I flushed the fuel system and hoses and replaced the old, with new petrol as it breaks down and oxidizes if left too long. I also bought fuel stabilizer which is essential to help prevent degradation of the fuel and helps with water in the fuel.
I renewed the gear casing oil with marine grade (expensive) and hey presto, a totally transformed engine that puts the 15' Seahog on the plane at about 1/4 throttle.
It has gone from being a worry (through no falt of its own), to being a superb powerful engine.