Carb problem
 

have an 89 b2200 with an 87 b2000 motor had to replace the carb. got a used carb put it in. all vaccume and fuel lines are on right. turn it over it idles as soon as you step on the gas it stalls out. it has gas going to the carb fuel pump is working fuel filter is only staying half filled with gas. any suggestions what the problem could be???

I would check the fuel pressure first to make sure the fuel pump is supplying enough fuel to the carb.