With HS6's I haven't had a fuel foaming issue, but with my previous TR4, with
H6's I struggled with them as Tony describes. I did three things and solved
the problem. First I tried safety wire to secure the float bowls from shaking
so much, with limited improvement. Second I had been advised that it was best
to weld up the tranny mount into a solid mount to avoid failures , but I
determined that this added to the resonance issues. I now fill the cavity of
a stock mount with silicone, gradually so it cures. This is the "Air Triumph"
mount. Lastly I placed 2" o-rings between the insulator block and the intake
manifold surface (or was it the carb surface?). I used a 2" hole saw to cut a
locating groove in the insulator and slightly longer studs to mnount the
carbs. Worked for me.
Bob Kramer
-----Original Message-----
From: fot-bounces@autox.team.net [mailto:fot-bounces@autox.team.net] On Behalf
Of Tony Drews
Sent: Thursday, May 26, 2011 12:40 AM
To: Duncan Charlton; fot@autox.team.net
Subject: Re: [Fot] Sputtering TR question
I doubt this is the issue, but one issue that Jack had was a little
piece of rubber from where the jet tube comes into the float bowl -
it allowed enough fuel to get through that it ran but would
occasionally block the jet causing the car to run like crap. Took
over 5 carb disassemblies before it was found. Different symptoms to
what you are having, though.
If you have a fuel pressure gauge and EGT gauge (front and rear), you
can tell whether it's going rich or lean.
We fought issues with fuel pressure regulators (goes lean at end of
long straight - pulling back on the gas pedal helps) and with
vibration causing the fuel in the carb bowl to foam (goes rich -
nothing you do with the gas pedal helps much), as well as the
orientation of the top of the float bowl (one goes rich - keep the
revs way up and the problem lessens as you clear the extra fuel more
quickly).
With the resonance deal foaming the fuel, it seemed that once it got
started it would continue but if you could eke through the RPM that
caused the issue the resonance would stop. It wouldn't always
happen, though. This is a possibility, although what you described
as trying for the workarounds should have taken care of this issue.
Assuming that it is fuel related, it's a good idea to take the carbs
apart and make sure everything is completely clean - no dirt in the
bowl or lines.
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