Since you have the hand pump... pump it 20+ times and try again. I've been running a machine which will run out of fuel when run on a side slope. It has two tanks and when not that low on fuel it sucks air from the uphill tank. While most will say " NO WAY " I pour gas into the air cleaner, loosen 3 of the 6 injector lines at the injectors and crank it up running on the gas fumes long enough to let me turn the machine to up hill. Tighten the 3 lines and there's still enough gas fumes to crank it again and it usually runs normally as it has an electric fuel pump.
Not sure if you have a grid heater but if all else fails I'd disconnect it and put 3 oz of gas in the air intake and crank it up. Takes a while for the fumes to get through CAC air cooler. Yes I've been called shade tree and I buy starting fluid by the case but in the summer I like gas better.