cub won't start

rebuilt old cub. took a few years. Put a Ignitor kit in the distributor. Go to start and it won't run. I checked and all plugs getting fire to them. Carb seems to have gas in it. 6 volt system all new stuff. Has good turn but just doesn't seem to catch and run. ideas?

are you sure that the cam and distributor are timed correctly? Is it firing on TDC on #1? Are the valves timed right?

Did you pull the distributor? If you did, you may not have it in time when you reinstalled it. Hal

1342 is firing order if timing is right check dist cap I gad a prob. with one of those once.

Did you rebuild the carb? Most aftermarket kits are crap. Common Cub problem.

Grand-dad was an old-school mechanic, and he taught me the first things to look for with a "cranks/won't start" complaint:

You need to have (a)air, (b)fuel, (c)spark, and (d) in the proper amount, and (e)at the right time. This is assuming the rest of the engine is healthy. All other diagnostics are mere details.

Not trying to talk down to anyone, but these Cub engines are pretty basic. So it helps to not overlook the basics when diagnosing a starting problem.

Hold your hand over the throat of the carburetor while a helper makes an attempt to start the engine to see if there's much suction. Very little suction means your intake manifold vacuum is low which is needed to suck that fuel into the engine. Check your manifold and carburetor to make sure they're not leaking. Pull the sparkplugs and pour some engine oil on top of the pistons then crank over the engine a few times and replace the plugs then see if the engine will start. Hal

ok, let's make a short laundry list here. First, Jeep said he rebuilt this thing, so my assumption is that the crank was out, the cam was out, distributor was out, etc. so, let's start here:

1.) check compression. all cylinders should register close to the same pressure. If the CAM is timed right, and the valve lash is right, then there should be decent compression. No compression, then there is a valve issue (timing or lash).
2.)Check spark at TDC on number 1 and timing order (wiring). If the rotor is not at 1:00 when #1 is at TDC, then there is a timing issue with either the distributor/Mag gear or the distributor itself. Also, are the wires on in correct order 1,3,4,2 starting at 1:00 on the cap, and going clockwise.
3.) vacuum. If the valves are timed right, and there is compression, then is the manifold leaking or anything else in the fuel supply path (carb, manifold).
4.)Fuel delivery. fuel may be going to the carb, but is the carb delivering fuel. Best way to check very quickly is with the air cleaner hose off, and a helper running the starter, spray some ether into the intake on the carb while cranking. if it fires then dies, you have a fuel delivery problem in the carb. BTW, this test should be done AFTER determining that the timing and firing order are correct. you really don't want to be spraying ether into an engine that may backfire.

If you go through all these steps, and she still won't run, then I am stumped. (that is based upon the fact that you state you have good spark at the plugs.)

my $.02 worth.

Great list. First time to use TDC at #1 can you explain how to
perform this. Thanks