MTD 13AE541F000 rider mower Teh 12.5 hp XL/c endura I overfilled the oil, just a little some time ago(2months ago). oil level is OK but havent changed in a while. It was hard starting about 2 weeks ago and ran surging. The surging would get less after warm-up, but returned just I was finishing mowing. Now it won't start. It will run after I put gas thru the top of the carb, for about 4-5 seconds. Ive replaced the spark plug, fuel filter. The carb bowl is filling with gas. The fuel line is clean and clear. The spark is working. After cranking, I do NOT smell gas. Ive taken the carb off and cleaned with carb/choke cleaner. Nope, no start. Inside the bowl, theres a black nipple thing, with very small holes in it that goes down in the center hole, on top of a spring. That little nipple thing had a small O-ring on the end of it. The O-ring was in really bad shape. I replaced it. After I removed the carb, the blade things were clean and moved freely. There were several small holes (where the bowl attaches) and they were clean and not obstructed. Couls the "jets" be clogged? I don't even know what a "jet" looks like or where they would be. It seems like the gas isn't getting up into the carb. There isn't a fuel pump(it's gravity fed) There isnt a oil pump or oil filter. What to do?

Shifter in my Murray riding mower is frozen. I can force it into R and 1st gear, but nothing else. I suspect the gears inside are rusted as the mower was under a tarp that leaked! I've found a diagram of the Peerless/Tecumseh 930.032 tran but it doesn't show me where all the bolts are that hold the darn thing up under the tractor and w zero clearance underneath I can't inspect it properly. Any help? Also, is it OK to tip the mower onto it's backside-tailend to work on it? Thanks a million! My grass is knee high........