1) Too much fuel pressure. SUs don't like anything over 2.5 PSI.

2) Sinking float in front car.

3) Float valve stuck open with dirt.

 

Awesome, I will check those things.

 

If the fuel pump is the OEM mechanical unit bolted on the block be sure the plastic spacer is of the correct thickness and has a gasket on both sides.

Crank up the engine until the carb starts to spit then shut down immediately and remove the float bowl lid on both carbs to see if the fuel level is the same and if either float is leaking and sitting lower in the bowl.

Confirm that there is no crud in the bottom of the float bowls or in the jet tubes.

What type of float needle is in the carbs?

George Dill

 

A rip in the hose or loose clamp will do it too. Kinda looks like it in the video.

 

Cheese grater clamps - these should be banned and the inventor castra...

Could a too-tight clamp...?

George Dill

 

Fixed it. There was a bunch of dirt and gunk in the float tank. Cleaned that sucker out, works great.