1994 GTX wont pass 20mph

[Shippy]

I have recently purchased a 94 GTX and at the time of purchase it had grey fuel lines on it (ran fine when i bought it). I have gone through replaced the fuel lines, fuel filter, peacock, and cleaned the carb with replacing everything in it. Set the idle and throttle positioned aswel as oil pump alignment. With it running fine out of water i brought it for a sea trial and it wont kick up above 20. It feels like it wants to take off but also feel like its being held back. I ran it back and for a couple times and noticed it jerks a little bit and that if i idle around for about 5 minutes it will go full speed but then slowly fall back to about 20-25MPH.

Could this possibly be a high/low speed screw adjustment or somthing els?

 

[mikidymac]

No, you are starving for fuel and will ruin the engine if you keep running it. I would make sure you don't have any air leaks in the fuel system first. What brand of carb kits did you buy? Did you check pop of and leak down?