Running out of gas

[Surface Scratcher]

At speed (usually 4000rpm & up) my carb 2.4 starts to run out of gas. It seems to loose one carb at a time. Then, when I stop the problem goes away for a while. By the time I can get to the primer bulb, it is full, but I really don't know what it's like when the problem occurs.

Also, I've heard that fuel line can collapse under suction. However, I replaced the line with automotive fuel line about 2 years ago. I also replaced the fuel pump diaphragm 2 tears ago. Ive checked it recently and it's look like new.

Where should I start?
Thanks

[ccrick]

From the tank forward. I've seen that type of hose collapse. Good luck!

[77viper]

Yep check the fuel line, fuel tank vent, filter, pickup in the tank. I use one of those cheap fuel pressure-vac testers with a T fitting at the pump on the vac side. It should read less than 3" of vac if it's more you have a restriction just a mater of finding it. If you pinch the line the vac should read around 10" vac, that is what the pump is capable of and tests the pump itself.

[silkeysak]

if you have a piece of trash in the tank or fuel line it will move forward when you throttle up and then fall away when it shuts down. If you're lucky that's all it is.