G2 Gas starvation
 

I picked up a G2 that wasn't running too well. I gave it a tune-up, pulled apart the carb and cleaned the jet. I changed the tank filter and filled it up with fresh gas. I also put another in-line filter between the carb and the fuel pump. When I started it up and it would then stall within 5 seconds. I took the carb hose off the fuel pump and there was very little fuel pressure. Hardly any pressure to even push the fuel up to the end of the hose. So next, I changed the fuel pump. It pumps strong at low throttle, but when I nail it, the gas dribbles out of the fuel pump and starves the carb for fuel. The secondary fuel filter that I installed doesn't fill up like it should.
So I checked the engine compression and it's very strong. A few of the plastic pressure hoses coming off the engine going to the the fuel pump were very brittle. So I replaced them with rubber fuel line. Would this make a difference in fuel starvation???

Check the air box to make sure it's sealed properly. I've heard that a slight leak will play havoc with the air/fuel mixture