You say "filter is clean," and I assume you're talking about the air filter. Have you changed the fuel filter? You could have an electrical/timing problem, but I'd eliminate the fuel problems first. You haven't given a complete picture on what's happening. When you're doing all this cranking, does it fire at all? Once it starts, does it run okay? Here are the initial steps I would take. Replace the fuel filter. Check the vent hole in the gas cap. Check all the fuel lines for cracks, crimps, leaks. Check the fuel tank for residue in the bottom. Test the fuel pump (as rcmoser said). Verify fuel solenoid is functioning (if your engine has one). Beyond those things, you'll probably need to get into the carb. If you're letting the machine set with gasoline in it for a month or more between uses, you should buy only enough gas to do the job, treat it with marine-grade stabilizer (such as Sta-Bil Marine or Seafoam), do your once-a-month mowing, and let the tractor run completely out of gas, leaving the tank and carb with no fuel. Old, stale, dirty gasoline is one of your machine's worst enemies. What's even worse is gasoline that contains ethanol. The 2nd-best thing would be to use fuel stabilizer in the gasoline, and, when finished mowing, park the tractor, close the fuel shutoff valve, and let the engine die of fuel starvation. Don't leave gasoline setting in your carbureter for a month at a time - this will lead to all sorts of problems - and this might be the problem you're having now.

A couple possibilities. That's a Briggs OHV engine. IF the valves get out of adjustment, the compression release doesn't function. OR, you simply have a bad connection in the cranking circuit. Clean the ends of all battery cables. make sure engine mounting bolts are tight. The ground side is just as important as the "hot" side. Then there's the possibility your battery has reached the end of its life. Charge & get it load tested to be sure. A bad solenoid is also a possibility. This post was edited by bill_kapaun on Sat, Nov 8, 14 at 22:34

Strangely, I left the battery charging all night and tried it again this morning, and it tried to crank, but didn't start, then the battery died. I hooked the charger up to "Boost" and tried it, and it started. I left it run for about five minutes, shut it off and then turned the key...it didn't want to start, but finally turned over and started. I then took the battery that was in it before this current one to Sears and had then test that one. After an initial draw at 12 amps, it dropped to 6 amps, so they suggested they try "restoring it", which I said ok to. When I picked up an hour later they said it was now good, and would probably last a year or two. To hedge my bet, I bought a new battery of similar CCA at Batteries Plus (it was about half what Sears wanted for theirs) I took them home and installed the reconditioned one and turned the key. Again, it didn't really want to start: urr...urr, but then turned over. Again, I ran it for a few minutes then shut it off and did about 45 minutes of chores, and then tried to start it. Again, it was hesitant, but did kick over, even without choking it. So, I guess my question now is: what could be causing the hesitancy, and obviously greater current draw? Starter? Any help is appreciated.

I show that tractor as having a KohlerCV674-75574. IF it's sat since Feb, there's a good chance the carb is clogged up due to ethanol fuel. You can prime the carb with a couple teaspoons of gas to see if it's a fuel delivery problem. Appearance of the filter can be deceiving. You can Google "Load Test". Basically it puts the battery in a heavy discharge state (as in cranking the engine) and checks to see if it has sufficient capacity. 8 penlight batteries will generate 12V, but not come close to cranking the engine because they don't have the amperage.