varnish in the gas tank

I just purchased a second hand yamaha 4 hp boat motor.<br />Model Yamaha 4MSHS<br />Serial number: 6GE0 S 146428<br /><br />When I received it I found that gasoline was left in the tank and it turned to varnish. (The former owner told me that this motor belonged to his deceased father and was without use for a couple years).<br />WE do not know the original year of purchase of this motor. <br />Questions: <br />A. What would I do now to get rid of the varnish? That varnish could affect somehow the motor?<br />Would it be OK to just remove the varnished gasoline and put fresh gas in there and start it?<br /><br />B. Do I have to mix oil with the gas with this boat motor (we do not have a manual)?<br /><br />Thanks for your help, we really appreciate it.<br /><br />Barry

Re: varnish in the gas tank

I would suggest removing and cleaning the carb. If the tank is varnished, the carb most likely is as well. With a manual and some basic tools, it is not terribly difficult to pull the carb and clean. Some fuel system cleaner vigorously sloshed in the tank, then drained should remove the crud from it. You will want a new impeller (water pump) as well before firing it up. Mix fresh fuel at 50:1 ratio with a good TCWIII outboard oil. First step: Get the book.

Re: varnish in the gas tank

Thanks for your time and your advice on how to deal with the motor. <br /> <br />Barry