Ok, I just bought an '86 force 50 that's been sitting for a couple years. It had a bad condenser. I replaced it, and it ran perfect for about 20 minutes or so. I pulled the plugs, and they were coated with oil. Turns out, I had mixed the gas at 16:1 instead of 50:1 (should have checked this website first). I'm getting ready to replace the gas, but I need to know if an incorrect mixture will cause it to backfire. When I try to start it, my neighbors hit the ground. Will replacing the gas stop the backfire, or is the timing off? Any ideas?
It has new points and condensors. I replaced all of them, b/c I didn't want to have to take that pesky flywheel off again. It seems to be getting a spark to both cylinders. Before I replaced the points and condensers, it only had spark to one cylinder. It ran fine, and now it is backfiring and won't start.
Remove the carb float cover and remove that gas as well. Disconnect the fuel line going to the carb and pump the gas in the fuel line with the primer bulb into a container. This way you are starting with fresh gas. Make sure the oil you use is outboard motor oil. If plugs are severely fouled replace them as well. 16 to 1 isnt going to hurt the motor but it will run like crap. I would try running on new gas first before doing anything else. Backfire can also be reversed plug wires or a busted flywheel key.
I'm working on it now. I just removed the bowl and drained the gas from the carb. I tried starting with fresh gas, but it still just backfires and doesn't even try to start. I just did a little research on that flywheel key situation. When I removed the flywheel to replace the points/condensers, it was really hard to get off. I broke 2 gear pullers, 1 steering wheel puller, and pulled the band completely off of the flywheel assembly. I had to take it to a machine shop so they could press it back on. I thought that the flywheel nut was just tightened too much, so when I put it back on, I didn't use and impact wrench. Instead, I just tightened with a breaker bar and gave it a few taps with a hammer. Do you think I sheared the key by not tightening it enough? If so, do I need to take the flywheel off to check it? And...on the subject of flywheels, is there an easier way to get this thing off? I'm afraid I will trash it if I try to take it off again with a gear puller.
One of the main causes of a flywheel key breaking is because the flywheel nut was not tight enough. Hope someone else can offer you some advise on taking the flywheel off. If it was slightly siezed last time that might explain why it was so hard to get off. Maybe this time it will come off a lot easier.
Well, I got it off. A little easier this time, but still a pain. Used a harmonic balancer puller and ended up having to smack it from the bottom with a hammer and an assortment of metal objects. Anyhoot, as I thought, the key was sheared off. A place about 30 minutes away has it in stock (yeah, I was amazed) but I won't get a chance to put it in until Friday evening. Thanx, everyone for the help!