My parents just gave me a boat with an 1985 Force 85 hp motor. With little instruction and no owner's manual, I took it out to figure out how everything works. The motor has very low hours on it and has been serviced regularly. It ran with no trouble my first time out which was only for about an hour. I later learned that I made two mistakes.<br /><br />First, I didn't know that I was supposed to mix oil with the gas. I now know to use a 50 to 1 mix. My second mistake was not to open up the air valve on the gas tank to prevent a vacuum. The motor ran fine despite my mistakes, and I was only out long enough to burn about 3 gallons of gas.<br /><br />I tried taking it out again yesterday, this time with the proper gas/oil mix, and with the air valve open, but this time it wouldn't turn over. It has a new battery and is cranking good, and it occasionally sounded like it was going to turn over, but it never did. I tried putting a little gas into the spark plug holes, but this didn't help either.<br /><br />Any advice as to what I should try next, or how much damage I may have caused would be greatly appreciated.