Small Engines (Lawn Mowers, etc.): engine problem, internal passages, lawn mower

Question
I have a lawn mower 4cyc engine (BRUTE), and if i cover the air inlet partially (carburator), it starts, but otherwise starts and stops. I checked the spark plug and it looks OK.

any sugestions?

many thanks

Answer
You will need to clean the carb thoroughly including pushing a piece of tag wire through all of the internal passages.  Covering the air inlet on the carb acts like a choke and allows the engine to pull fuel from all available fuel circuits within the carb.  Hope this helps.