Small Engines (Lawn Mowers, etc.): Craftsman 6.75HP mower wont start, float chamber, gas flows

Question
Dear Michael,
    Recently bought a used Craftsman 6.75 HP mower model 917.377991 that had very little use.  We've checked the following items:  -spark ok, plug ok, compression ok, blade not damaged.  Gas flows into float chamber ok, found dirt in main nozzle tube and bowl drain screw.  Primer button seems inoperative. And, on sitting overnight, have a strong gas odor..with no sign of a leak.
    We would appreciate your expert help on how to proceed.

Dave

(year of mower, guessing approx 1999)


Answer
Hi Dave,

With no leaks, the odor may be normal and coming from the tank vent.  With spark and compression okay, timing unknown for now, I suspect a lack of fuel flow to the engine.  Try to start the engine, while squirting gas or starting fluid into the carb intake.  If it starts, 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.  I have had to re-do a carb several times to find that I missed just one small opening.

Let me know how you make out.
Michael