Hmm, when I did mine I did not have the problem. I went by the
instructions in the Haynes for setting up after a rebuild. OK, I forgot
to connect the main linkage spring ( I did not have one...) and had the
linkage locked with the mechanism half way at idle so could not get full
throttle.... But apart from that it was OK.
Did you do all the settings of all the way and then back the requisite
no of turns for the jets and the idle settings. Are the needles in
correct and level?
With the engine running at 2500 rpm how is the air flow to each carb?
Are they near balanced? ( screw the idle screws on both carbs done until
the revs stay, then loosen the linkage and check the air flow balance).
Have you checked for air leaks at the manifold? Are both float bowls
full of fuel.
or you could try - With the idle set high try balancing the carbs and
then see if the pin that pushes the piston makes a difference (or lift
the piston with a screw driver). Revs should change slightly up or down
depending upon state of tune of the carb. If nothing then carb isn't
doing anything.
Does adjusting the idle screw with the carbs separated make a
difference. It may be running on one carb. Or the pistons could be
sticking. I have seen the effects of gunk and deposits sticking the pistons.
The other thing I use is a Colourtune. If you have one or access to one
it may show what the cylinders are getting.
Wish you guys were closer. I love tinkering with SU's, at least on the
Spitfire. Austin Healey and MGB are a pain to work on in comparison due
to restricted access to the jet adjusting nuts - I have done cars both
with twin Colourtunes. Spitfire is by far the easiest to work on. You
don't get burnt and linkages are easier to tighten without losing the
balance.
Alan
Howard Baugues wrote:
>Calling on the list wisdom again.
>I have my 1.5" SU carbs installed on my 76 Spit. It started, but would only
>idle high 2500+rpm with the choke out or the pedal pressed down. It would not
>idle down and stay running. If I let off or let the choke back in, it would
>die.
>
>Any suggestions? Where should I start?
>
>Thanks in advance,
>Howard
>
>
>
>
>
>Scott A. Roberts wrote:
>LET ME KNOW TOO, PLEASE!
>
>Scott
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