Help To Start a 440

Is this a new build, or had been running "right" and now won't? And what is it in, year, model, and what do you have for carburetion and ignition system?

Checking spark...........rig a "gap" either a spark tester or a plug to the coil tower and ground. BEST to use a solid core wire and not radio suppressor wire. Crank the engine USING THE KEY and that is important

With a solid core wire, you should get nice blue snappy sparks at least 3/8 and typically up to 1/2" or more long

How 'bout cam timing? How did this all come about.........IE did it act up and run rough and then won't start, or did it just stop, or what?

Have you checked compression? I try to check both compression with gauge, and do a leakdown, the two go together and may help a lot to diagnose

Have you examined the plugs? dry? wet? Have you inspected the dist. rotor/ cap for dirt/ moisture/ carbon tracking etc?

How do you know it's getting fuel and IS IT FRESH and IS IT PROPER?

(Decades ago a then friend was priming down the carb throat, new build would not fire, turns out HE WAS USING JET FUEL (kerosene)