Time to get the mower out for the season but it was running fairly poorly at the end of the last. Anyone have any suggestions? Here are my notes from what happened last season.
Prime
Pull Start
Runs strong
Slows
Starts to die
Spary carb cleaner into carb 'straw'
(prime bulb expands)
Revs up
Runs 5min dies
(carb spray)

This cycle continues, than gets progressively shorter
Pumping primer bulb helps
Carb spray not so much

Removing gas cap does the trick

Have cleaned out fuel filter once and it needed it

Float seem to be operating correctly - way to test?

Again, any help/ideas/advice and or direction greatly appreciated.

Would like to fix/repair this myself, but can take it in if I have to.

Thanks,
Steven
Denver

Check for major air leaks around the carb. mounting area and the primer bulb.
Also, check to make sure the fuel cap is venting properly. A cap that doesnt vent properly will not allow fuel to flow to the carb.

In your question, taking the fuel cap off keeps it going? Then thats your problem, replace the cap.

sounds like the vent hole is plugged or damaged, not allowing gas into the carb. You know, it's like when you shut the vent on the gas can while pouring it, doesen't work very well.