I have a Simplicity Broadmoor riding mower, 14 hp Kohler Command engine. It starts (kind of hard) but runs good for 15-20 minutes, then sputters, and stops running. My understanding is that it runs out of available fuel. The fuel filter, situated right before the fuel pump is clear. When I first start it, the filter is full of fuel. After it’s running, the filter empties, seemingly faster than fuel can be replenished back into the filter. I have to let it sit for about 15 minutes, allowing the fuel to descend out of the tank and filter is full again. Starts, runs, then dies. New carb installed did not fix the problem. And recently I replaced the stock fuel hose with another run from the fuel tank opening down to filter, with no improvement. Please help!