jeudi 4 décembre 2014

This you don't see every day

I picked up a JD STX38 black deck with a Kohler Command 13, CV13S, it's a single cylinder OHV. The mower only needed a few cosmetic things so I finished it off and had it looking great and went to take a victory lap around the yard when all hell broke loose. It sounded like it had slung a rod but it was still running and still seemed to have ample compression. I shut it down quickly. Expecting the worst, I decided to open it up before I scrapped it just in case it wasn't as bad as it sounded, which was real bad. I took off the valve cover and everything seemed in order, no obvious damage. I removed the head cover and after some inspection I noticed something odd, a shallow indention in the piston head, it did not go through, just an indention. I looked at the head cover and saw a small piece of metal imbedded into the head cover. I removed it and saw that it had stamped a flathead screw intention into the head cover. I could make out a few threads in the now almost flat piece of metal that allowed me to identify it as a very small screw, or at least what once was.



To open the crankcase I would have had to remove the engine from the mower so I decided to wait in case that was not necessary. I put it all back together to see what it would do. I went ahead and cleaned the carb while it was off. The carb was working good before but I figured a cleaning wouldn't hurt. As I was cleaning it I discovered that one of the two choke plate screws were missing. Obviously I knew right where that other one was.



I put everything back together and double checked it all. I have good spark, good fuel delivery, the carb float is working properly, I dropped the bowl and checked that the float was shutting off the fuel and allowing it to run when the float is dropped. With the head cover back on I checked to see that the valves were opening and closing properly. I had checked the valves for damage since the screw obviously passed through the intake valve but saw no obvious damage. The valves are non adjustable hydraulic. I did not mix up the intake and exhaust rods.



When I try to start the engine now it spits fuel out of the air cleaner and when I close the choke it backfires. It will not turn over. Any suggestions?


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