I too am trying to deal with these "problem child"
carbs. I've rebuilt and replaced all the gaskets,the
jets,throttle shafts,air filters. I've even considered
changing the air in the tires if I thought it would
help. The problem seems to related to the choke.It
won't start or run with out it. I am out of ideas(and
patience).
Dave Gebhard
1977 Spitfire(not running yet)
----- Original Message -----
From: Terry L. Thompson <tlt@digex.net>
To: <spitfires@autox.team.net>
Sent: Wednesday, May 03, 2000 10:17 AM
Subject: Another carb question
It turns out that these HIF4's are still giving me a
problem. And before I
brake down and spend the $75 (quoted price) for a carb
adjustment, I'd like
to get some opinions to see what I can do to fix them.
With the car at operating temperature, I balanced
(using a unisyn) and tuned
the carbs. When you lift on the damper pin, the idle
tone rises for a second
then drops to the idle before I lifted the pin. And it
does this on both
carbs. The car idles under 1000 RPMs when warm (I
estimate between 800 and
900 rpms by the gauge).
And when driving the car at temperature, it seems to
run fairly steady, but
occasionally I get a studder or a pop (small
backfire?).
Also when the car is cold, giving it throttle seems to
give a smooth
accelleration. But when the car is under load (I put it
into gear and try to
drive), I get all kinds of shuddering and popping and
backfires. This
continues all the way up to when the temperature needle
is pointed straight
up (warm). Pulling the choke appears to help a little
bit but mostly seems
to make the RPMs increase.
Anyone got a clue as to what it might be?
Terry L. Thompson
'76 Spit 1500 w/HIF4's (from a 72 MGB)
Maryland
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