Small Engines (Lawn Mowers, etc.): Toro mower dies after 5 minutes, inductive timing light, fuel tank

Question
I have a 3 year old Toro GTS lawnmower with the 6.5hp engine.  It has always ran fine until two days ago.  I ran out of gas while mowing, purchased new gas, filled up and started mowing again.  It ran fine for a few minutes, then started sputering as if it was out of fuel again.  I let it sit for a short while.  It started fine and ran for maybe a minute and then did the same thing.  I checked the air filter and found it to be extremely dirty.  I replaced both the air filter and spark plug.

I tried to mow again yesterday.  It started normally but after five minutes it began to miss and stutter and finally quit.

What next?

Dean

Answer
t sounds like a couple of things could be happening. This could be caused by the fuel tank vent being blocked. Try loosening the cap if the vent and running. If it corrects the problem, replace the cap. Another possibility could be an ignition problem caused by heat. You can connect an inductive timing light on the plug lead(s) and see if the ignition cuts out when the engine dies. Another issue could be incorrect valve lash. You would need to adjust the valve lash to the correct clearance. Hope this helps.