[TR] Float bowls overflowing

[Roger Elliott]

Hi,

I have a 1980 Spitfire with dual SU HS4 carbs.  I noticed while trying to get to run correctly that the front fuel bowl had gas coming out the top vent hole.  

Figuring that it was the needle valve sticking, I replaced the needle valves and floats in both fuel bowls.  

The front bowl (second in fuel line) contined to overflow.  I thought that there may be a crack or something in the lid, so I dug out different lid, put the new bowls and valves in the lids, made sure the float adjustment is correct. 

These lids have vent tubes, which I have connected with fuel hose - above the carbs.
 
Well, gas is coming out of the vent hose connected to the vent tubes  - not sure which carb is overflowing at this point as I did not think to disconnect them until after I stopped working on them for the evening. 

The fuel line now has a T-connector to get gas to both carbs.  Previously, the rear carb had a fuel pass through.

I have a mechanical fuel pump, not original.  But one sold by one of the big vendors - don't remember which now.

Can the mechanical pumps put out too much pressure?  The pump has been on for a few years and it has run correctly in the past.

Assuming I haven't botched installing the needle valves and floats, is there anything besides excess fuel pressure that would cause the bowls to overflow?

Thanks,
Roger Elliott
1980 Spitfire