This motor is on a 1994 Murray riding mower. The initial problem started last year when I lost spark in 1 cylinder. I replaced the coil, regained spark in both cylinders. But now this season, it will only run if gas is poured into carburetor, it seems to have vacuum but carb won't pull gas through. I replaced the diaphram, springs but none of this helped. The gas is pouring into the engine oil, it seems to be making oil. Is this a sign of an internal problem? I am completely stumped at this point and any help would be appreciated. If the engine is shot, I don't want to keep throwing money at it.
Thanks
Dave Jackson

Do you have oil in the air cleaner?

Sounds like your float is not closing all the way. Excess fuel flows into the cylinder and seeps past the rings raising the oil level. Clean or replace the needle valve and seat, dump and flush the crank, put in new 30W

Thanks for the reply. I give it another look and see what happens.

A sticking fuel valve seems most likely. Wanted to rule out oil breather. Use Seafoam in small amt. of gas and/or dissasemble and clean carb.

Bb:
A float on a diaphram carb?

KISS: I think this B&G has a float carb. I have 2 newer V twins with floats but not 100% certain. What with all the gray rating marks we are getting this week?

The OP said "replaced the diaphram" though.

Grey - color of the week

This one has a diaphram pump on the front and a float inside the bowl.

Then the fuel valve is sticking. It's activated by the float.

I agree KISS that's about all it can be.