Hi,
I too have an '80 Spitfire. Some of the most mystifying problems I had
were related to carb and emission control stuff. I had a combination of
hard starting, sudden loss of power on the freeway (which went away if I
slowed down for a while), and inability to restart the car when hot (it
would catch, then suddenly die). All these problems were caused by a
faulty float valve! The damn thing would stick open, and depending on the
circumstances would:
1. Overrich the mixture causing performance problems.
2. Back up gas into the carbon cannister through the float bowl vent,
blocking the airflow to the anti-runon valve. This would simulate
activation of the anti-runon valve!
It took me quite a bit of pondering to figure it out. Finally, I was
messing around with the float, and one part of the needle valve fell out!
At this point, I finally got a clue.
There are at least two kinds of float-bowl needle valves (supposedly OEM)
available. One is real OEM and works pretty well. The other is crap.
Play around with the one you have, after taking it off the carb. If it's a
crummy one, you will be able to get it to hang up in the open position if
you mess with it for five minutes. The good kind may have a little
friction, but you won't be able to get it to stick. They look pretty
different, but describing the differences would be beyond my skill. By the
way, Grose Jets are worse than either in my experience.
As far as I can tell, there's no way to get a late spitfire to run well
unless you either spend a lot of time figuring out all the emissions stuff
or you take it all off. Since I live in California, I choose the former.
Hope this is of help.
AC
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