3 cylinder Cummins in a New Holland skid steer runs good for about 5 minutes, but once it warms up, it puffs and poops like it's starving on fuel. I put on a new manual fuel pump which didn't make a difference. I then put on an electronic fuel pump to force feed the manual pump, and the motor still ran good for a few minutes, but then after warm up, started acting the same again. when it runs good cold, the fuel return to the tank runs a good stream, but once it warms up, the amount of fuel through the return line is almost nil. that is why I'm assuming it's running lean once warmed up. any help would be greatly appreciated.
