I am having a similar issue with a similar motor.
Did you ever solve your problem?
Ever figure out ow that check valve works? The one at the bottom of the float bowl?
Fuel comes out of the pump on mine too, but I’ve chalked that up to the fact that fuel comes out of everywhere on motors older the 1954.
Ha!
I’m hoping by restarting this topic, because there are pictures of what I tried to discribe in my own, some ones memory will be jogged.
It’s a common enough motor, but info seems to be lacking.
Thanks,
G