Do i need to repair my boat engine?

relax, unburned engine oil dripping from the exhaust is not uncommon. It has that dirty dark appearance because of all the carbon build-up in the cylinders, ports, exhaust tube, etc. Easy enough to find out if it's gear oil -- just drain the gearcase; if the oil has a streaky or milky appearance, it's got water in it. Post another question on how to pinpoint the source and fix it. Assuming it's engine oil, here's what to do: First, if your spark plugs aren't Champion QL78C gapped at .030, change 'em. I have nothing against other brands, but your engine was built around that plug and that plug is what will make it happy. If you do a lot of trolling, then widen the gap to .040, and make sure you finish the day with a nice long run at WOT. These motors are bulletproof, but they're tuned to run flat out, and need to do so in order to keep carbon from building up in the cylinders. Add a decarb additive to your gasoline. I always add an ounce of Seafoam per gallon. Mercury, Yamaha and OMC ...  more