Step back and slowly retell the chain of events, it isn't likely all that complicated, but the stories of the broken crank and gas tank fires, drills, etc., are
a tad confusing. The last time it started and ran, what happened? Did something happen while trying to start it, while using it, hit a stump?
Then what did you try/do? What after that? What broke the crank? The fire happened after you tried to repair it?
At this point, I would say that you have an intake valve not fully closing, but please give us the needed details.
Okay. So here is the story. My dad went to a yard sale and bought a Kee mower deck. I guess they were really nice back in the day or whatever. The guy threw the Briggs 5HP on it for free. But, it did not start, even with fuel in the tank. So, me being in BMW STEP, graduated now, considered this to be an easy tackle, small engine, no start, must be the carb. So I sprayed ESF into the carb, and it did not start. I thought "hmm the carb must be blocked allowing nothing to go out". So I tilted the engine upwards to help the fluid flow into the intake, and I finally was able to get it to turn over. So, I decided to rebuild the carb. I did so, and still nothing flowed. Then, I rebuilt it again, and nothing. So, I turned to spraying fluid into the intake, only then was I able to make it turn over. So, I bought a new carb and fuel tank. While waiting on the carb to ship, I took off the head and inspected the upper cylinder, nothing out of the ordinary, some carbon on the valves, some on the head, not very much on the piston head. Also, there were not really any scratches on the inside of the piston, so i assumed it had good compression. Then, still while waiting, I thought that using the drill to start it over the pull start-recoil, would be better, since it would make less wear and tear on my recoil assembly. So, I would spray fluid into the intake, turn the drill, and it would make some revolutions before it all evaporated. Finally the new carb and tank arrived, put gas in it, hooked it up to the intake on the engine and viola! It ran :thumbsup:. But, I was going to reassemble everything, and I did, and I thought that I could start it and fiddle with the fuel/air knob to get it to run nicely. Well, the pull start was unable to start the engine. No amount of me pulling was able to get it to run under its own power. So, I took it off, and hooked the drill up to it (15/16 socket, extension, and drill, usually, the drill would do about the same number of revolutions before it wanted to recoil) and it started. I also had the choke pulled out if that makes a a difference. Well, as I was trying to adjust the fuel/air knob, the extension orbited out of the correct orientation and caused the shaft to break (including the clutch) just under the flywheel. I put it all back together and ordered the parts.
Fast forward to this past week. It installed new piston rings, then put the crank shaft in, aligned the cam with the crank shaft, after installing the connecting rod and splasher. Then installed a new gear case gasket. Then, installed the head. I turned the PTO end of the shaft a few times to make sure I could hear compression, and see the valves move. I also put while lithium grease on the part where the flywheel goes, and for the connecting rod space as well. Also put some on the PTO end. I also filled it up with oil. Then came the first test, no luck. This was with the carb removed. I pulled about fifty times, and it only got close to making power under its own. I was also spraying ESF because without it, I would not know if there was a spark. So, no luck for a while. Yesterday, I was able to get it to pop after pulling it once or twice (out of what seemed to be about a hundred tries, literally). All of the pulls, I used ESF. Now, I hooked the carb up and put gas in, and still no luck pulling it. Not even on choke, adjusting the knob, putting ESF into the head OR the carb, nothing, though it seemed to be getting very close. Then I figured out how to hook the drill up, and tried it that way. I seen a flame out of the exhaust hole and thought nothing of it. A few tries later, and the outside of the carb caught on fire (loose gas mostly) then I sprayed it down carefully, and let it sit. I did what you guys suggested last night and the key was and is intact. I took off the head this morning to inspect the valves, and they looked liked they were fine (I can provide photos for your inspection) but there seemed to be gooey carbon on the head of the piston and cylinder head (I scraped it and removed it). I replaced the spark plug as well. I know the flywheel is providing spark and the coil because I held onto it as someone else pulled and it gave me a good little tingle. I tried to start it with the carb removed and it caught on fire again. I looked in the breather hole and the springs for the valves, im not sure how to recognize them on this engine (if its right or wrong, again, I will provide photos for your inspection). I try it with the carb off because that is how i confirm igniton, if it runs for a few seconds, then we are good. But, no such luck. I hope this helps. The valves also moved when i turned them with my thumb. Also, today, I was using the pull start, no more drill after the engine caught on fire.
