Hello, I have a 17.5 hp kohler cv491s on a 2004 deere riding mower. At 40 hours the engine through a rod. I disassembled the engine, the crank was okay so I polished up a little. I replaced the broken connecting rod and reassembled. I am 99% sure of the timing mark alignments on the small gear and the large gear. After reinstalling I found the carb to be gummed up from sitting a little over a year. Fuel pump is fine so I cleaned the needle and seat etc. and the fuel shut off solenoid seems to be working-it clicks when plug and unplug with the key on. Now backfires through the carb all the time and will not run. Is there anything that could cause this other than the timing being off?