Small Engines (Lawn Mowers, etc.): Motor stalls under load, float bowl, fuel flow

Question
I have an Onan 10.9 HP riding lawnmower. I rebuilt the carb and cleaned using solvent and compressed air,removed the fuel pump checked diaphrams and cleaned. Motor runs smooth at idle and when throttle increased motor runs very well under load until I move throttle up to it's full position. At this point the motor will run for 1-2 minutes under load then starts to miss and die. Engine always starts to miss after approx 1-2 minutes. If I throttle down motor runs good.
Other work completed: air filter cleaned, plugs and points. I put a see through hose between the carb and fuel pump and fuel is getting to carb.
I did not adjusted the float during rebuild. When I flipped the carb upside down with the float installed I noticed that the top of the float did not sit level with the base of the carb.The float was a good 1/4" below the carb base.  

Answer
Hi Todd,

I'm sorry for my delay.

The float level may be the problem.  It doesn't need to be level but should be parallel with the rim of the float bowl.  If that is okay, then there may still be a blockage in the carb.  Check for a lack of fuel flow while trying to keep it running by adding fuel or starting fluid to the carb's intake.

Let me know what you find.
Michael