2 1/2 years after converting my '80 MGB to HS4s I decided it was
time to retune them. When I took the lids off of the float chambers
to check the float levels, I discovered that I have the non-adjustable,
one-piece floats. The float height is about 1/4 inch instead of
the expected 1/8 inch. Adjusting the idle mixture, I started with
the jets at the recommended two full turns down from where they
were even with the venturi. Checking the mixture using the
lift pins, it was too lean at this point and it took at least two
additional turns down to get a proper mixture at idle.
So my question is, how, or should I be adjusting the floats on
these carbs? I can see how I could set them lower by placing
shims under the needle valve, but there does not seem to
be any room to adjust them higher.
I should note that when I tuned the carbs on my Healey (HS6s
with adjustable floats), the starting adjustment (two turns down)
was too rich.
Just as a point of reference, I have the timing on the MG set
at 14 degrees BTDC. The car has plenty of low end torque,
but seems to fade a bit beyond 3500 rpm. Sometimes I think
that I detect a hint of a miss between 60 and 65 mph in 4th
(3300 to 3500 rpm). Plugs, wires, cap, and rotor were all replaced
over the winter and I also adjusted the valves recently.
Any ideas?
Thanks in advance,
Peter Schauss
pschauss@aol.com
1980 MGB
1963 Austin-Healey 3000 Mk II
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