Outdoor Power Equipment and Small Engines - 18hp Briggs and Stratton hard or no start

What should I check next? I have a older single cylinder lawn tractor with a Briigs and Stratton 18hp. engine. It was getting hard to start and would only start after it would back fire through the carb a few times. I checked and reset the points. Now it just cranks with no spark. With my test light on B+ and the primary side of the coil that goes to the points, the light will flash (points Close) just before tdc, but no spark from the coil. I checked the flywheel and it does not look like it turned on the keyway and coil to flywheel gap looks good. Don't know the specs for sure. Thanks for any help.

go ahead and replace the points, sure the flywheel key ain't sheared? then move on to the coil gap, i use a dollar bill, get it so the bill pulls out with force, but doesn't rip, tighten the screws, then spin the flywheel to see if it rubs or not, adjust so it doesn't. still doesn't fire... try a little gas down the carb, if it does. carb needs a overhaul. if it doesn't, try it without the kill wire. if it does, bad kill switch somewhere, doesn't, coil very well may be bad. if it uses still uses points.... that engines old, if the carbs original, it may be time for the carb to be rebuilt anyway. also hard starting can be from low compression.

Have you replaced the condenser?
I find in older engine it's usually the problem. May times you'll see
they have been leaking.

It sounds as though you have a battery ignition engine (but I'm not absolutely sure) whereas you need a battery in excellent condition to achieve spark. Not just 12 volts but you need sufficient amperage to generate solid spark. What are your engines' ID numbers? More information will be needed to further help you out.