Roger,
I had the same problem with a 4A with HS6 carbs and an electrical pump. Turned
out that the fuel pressure was too high. I added a fuel pressure regulator and
dialed it down to 1.5lbs, car ran fine and no more fuel leaks (plenty of other
leaks but that's a different story).
That was 20 years ago and the regulator was about $12. I don't know where to
get one today.
Best,
Cliff
-----Original Message-----
>From: Roger Elliott <elliottr at rmi.net>
>Sent: May 10, 2012 8:56 AM
>To: triumphs at autox.team.net
>Subject: [TR] Float bowls overflowing
>
>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
>
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