Small Engines (Lawn Mowers, etc.): Snapper Mod.DP21357B Briggs 3.5 h.p., ketchup bottles, spark coil

Question
This is a walk behind and has been running fine till today.
Engine will start first pull,but runs about a min. and dies
as if out of fuel. I put in new plug and removed carb. bowl
float and needle valve and sprayed with carb. cleaner and blew out with compressed air. Also blew air thru line into
tank. After it dies it will start right back but does not run as long as first start. It seems a fuel problem but could it be the coil?  I did not remove the entire carb.

Answer
It could be a coil breaking down but coils rarely fail.  Usually the problem you have is carb related.

Do you have an inline spark tester so you can check the spark as soon as the engine dies?

An alternate test would be to use a primer bottle, like one of those squeezable ketchup bottles with the pointed tip you find in diners.  This is more dangerous but will tell you if you have a fuel or ignition problem.  When the engine starts to die squirt a few drops of fuel in the the carburetor with the bottle to keep the engnine running.  If the engine will run while you deliver fuel then the spark/coil is fine and you know you have a fuel problem.

Eric