Exactly. If i do not pour it directly into the carbs, it won't crank. It's a fuel issue.
There is more to ignition and running than just the starter motor running and engaging the crankshaft.
What I suspect Slumlord means is an engine "turning over" and an engine "cranking" mean the same thing. The starter is working, engaging the flywheel and rotating the crankshaft. But until the engine "catches" or "starts," it's only cranking or turning over. The cranking and the turning over are the mechanical rotation of the engine before it catches or starts.
So it makes no sense that fuel has anything to do with your engine cranking. What you likely mean to say is that the engine will not start / catch unless you pour fuel in the top of the carb while cranking. If that is the case then, yes your problem is fuel related.
Words and phrases have specific meanings, when someone is trying to help you diagnose a problem, especially when they themselves cannot confirm the issue, they must rely on your words alone, so it is very important to use the right words to describe the situation.
So does your engine crank when you use the ignition system? Meaning does the engine rotate as it should? If yes then it cranks fine.
Or is your engine failing to start while cranking unless you add fuel directly to the carb?
Or is it something else altogether?