Ok, he has a K&B engine with the fuel pump. The carb is a bigger bore carb designed for use with a fuel pump. It is dependent on a fuel pump to provide the fuel as it can't draw fuel very well itself. What you can do is use a Perry VP-30 style pump with the engine and he will be back to normal again. You can even get a regular backplate and epoxy, using JB Weld, the fuel pump back into the backplate and it'll look almost like a original pumped engine too. Don't forget to drill a hole in the backplate for the crankcase pressure to get to the pump. You could also just put on the regular non-pumped engine carb and not use a fuel pump. The non-pumped engine uses a smaller bore carb. Perry says the regular carb is a 1300 and the pumped carb is a 9300 for a K&B .61 engine.