I have a 20 year old 15 hp. Evinrude 2 stroke on my 14 ft. Valco. When we first got it, we couldn't figure out what the problem was. It started out rough and smoky as hell the first couple of trips out. Found out the last owner, who had only used the boat and motor maybe a half-dozen times over 20 years, hadn't bothered to completely read the directions. He told me to use 100-1 mix oil for the gas BUT the manual says use 50-1 after 48 hour break in peroid! So I changed the oil and mix and now the motor is real clean(for a 2-stroke:(

You know, I've never had problems to carburetors or all that other sh-t bcz I ALWAYS disconnect the fueal line to the tank and run out the gas left in the motor. Usually i'll do this while I'm unloaing my stuff out the boat at the dock. Tie up the boat before i leave and then go get the car and trailer ready. Usaully gettin' rid of all the gas left takes a couple minutes, so I also usually have time to get my rods and boxes out before I pull the boat out. It works for me.