Briggs & Stratton 122M02-0001-F4 spitts fuel air mix out of carburetor

Hello

I have a Briggs & Stratton 122Mo2-0001-F4 that is hard to start and only runs a minute or so and quits.

This engine is on a walk behind string type weed cutter. It has only had one tank 0f gas run thru it. When it quit like it ran out of fuel. Fuel was added and this 8unit has not run since.

Has good Spark, good spark plug and I have checked and made sure the gas added is good gas and not diesel or something.

What I observe so far is when primed with the primer ball the engine will start and accelerate to about half the rpm it should operate at and then stall. By removing the air filter and observing the carburetor intake port I see a lot 0f fuel / air mix spiting out of the carburetor intake.

I removed the air filter housing and when I put my thumb over the air intake when I pull the start rope I feel as much pressure as I do suction.

Now for some questions you all mite be able to answer.

Has any one experienced this condition and is it normal

Is there any valve lap on this engine and if so how many degrees?

Is there a compression release built into the camshaft?

Thanks in advance.

Phil P

Briggs & Stratton 122M02-0001-F4 spitts fuel air mix out of carburetor