Old Lawn boy will not run

[colly43]

Hi
I have a 15 year old Lawn boy walk-behind mower that will run for 3-5 minutes and then dies. I pushed the bulb that feeds gas to the carburetor (No Choke) and it does run for a few more minutes. I have removed the float bulb, flushed out the gas, and that made it run for about 30 minutes. Now it's back to 3-5 minutes. It is a Tecumseh Products, ENGINE FAMILY- YTPXS.1851BA DISP 185CC. The name on the fly wheel cover is SILVER ELECTRIC START, 5.0 hp. It's a 21 inch mower.
Rather than changing parts I thought I would run it by you guys to any expert advice you can give me.
Colly43

 

[kbowley]

The fuel cap vent may be plugged, creating a vacuum in the tank, or the float is sticking. Try soaking the fuel cap in water and dish soap for a few minutes. If that fails, the carburetor will likely need to be replaced with an OEM. What is the model of the Mower? Also, that is not the engine model; it should be something like LEV185xxxxxx

 

[Tiger Small Engine]

The fuel cap vent may be plugged, creating a vacuum in the tank, or the float is sticking. Try soaking the fuel cap in water and dish soap for a few minutes. If that fails, the carburetor will likely need to be replaced with an OEM. What is the model of the Mower? Also, that is not the engine model; it should be something like LEV185xxxxxx

Clean existing OEM carburetor.

 

[colly43]

Thanks for input. I did the soap and water on the cap and that didn't help. Also unscrewed the cap as the engine was dying and that didn't help. I attached the engine tag as I cannot find any other information on the mower, except on flywheel cover noted above. I will pull the carb tomorrow and use Gum-out. How do I fix a sticking float? I had the sediment bowl off earlier and the float was moving freely.

 

[Rivets]

Please the model and serial numbers off the silver ID tag located on the rear of the deck. This will help us better see which engine you are dealing with.