Small Engines (Lawn Mowers, etc.): Yard machine 12hp, fuel flow, gas cap

Question
Hi you have help me before with this mower, but this time I hav two problems (1)the mower when I start it , it will start but onece it is turned off it won't start again unless I wait till the next day to try it. the next problem is once the mower runs for about a few minutes it stalls and then dies, and then I can't start it because of the first problem, but if I wait till the next day it will start or it has so far.I just replaced the sylenoid, and I don't think it is that, what do you think.

Answer
Hi Mary,

You will need to determine if the problem is a lack of spark or a lack of fuel flow.  Right after it quits, remove the spark plug, reconnect the wire and lay it against the engine head.  Pull the engine over and watch for spark at the plug's electrode.

If good, then try to start it while squirting fuel or starting fluid into the carb intake.  If it starts and you can keep it running by adding fuel, then the carb most likely has dirt, debris or gummed fuel inside.
You will need to remove the carb, disassemble it, clean all the small internal openings and blow it out with compressed air.   Probe each and every hole with a small wire.   A carb rebuild kit wouldn't hurt either.  

Another possibility if the problem is fuel related: Check the gas cap to make sure it is venting and not causing a vacuum in the tank.  

Let me know how you make out.
Michael