txninak@arctic.net
Cadet
- Joined
- Jul 9, 2003
- Messages
- 6
I have a 1999 Yamaha F50 4-stroke, which I have used for three seasons with no problems whatsoever. To winterize, I have added a gas additive and run the engine dry prior to putting it up for the winter. I did not until this year realize I could drain the remainder of the fuel from the carbs, so likely a small amount of fuel has remained in them over each winter. New gas has been used at the beginning of each season. <br /><br />This year, the motor has performed inconsistently, sometimes running well (usually at high RPMS, above 3000), but at both high and low speeds it will sometimes miss and lug. I have cleaned all the fuel tanks, lines and filters and replaced all the gas, again. Upon draining the carbs, I discovered a blue crystalline substance that breaks into a powder when you press it. It does not dissolve in gas or in carb cleaners, but repeated application of carb cleaner directly into the carb seems to flush it to the bottom of the bowl. I'm assuming this sediment is what is causing the performance problems; however, what is it? where did it come from? how do I get rid of it? and how do I keep it from coming back?