Carl Stern writes:
> I have the same problem with my 74 MGB also with HIF4s. I was about to
>purchase a Colortune to get the adjustment right, before I resorted to a carb
>rebuild. I also checked valves, ignition, etc. I thought the Colortune would
>do it since you and Scott seemed to have good luck with it initially. I'm
>wondering about the worn throttle plates that Scott mentioned. Also Moss
>has a note in their catalog about those spring loaded valves (can't think of
>their real name now) in the plates themselves and recommends soldering them
>shut. Anyone done this?
> Mine actually runs real well on the road, just not at idle. It loads up,
>and the idle speed keeps dropping..
> Carl
Soldering the spring valves shut is not legal in all states, as the catalog
states. Also, I don't recall the effect this would have (richer or leaner).
Anyway, I'm trying to avoid any non-standard modifications since this carb
was just fine recently and I will be looking to pass the idle speed smog test.
I would still recommend a Colortune!! It makes short work of the tuning
process, but it's only a gauge, like a timing light. If there's a
problem, the Colortune won't help fix it, but it will help you find the
trouble.
I stopped at Burnett's this morning and was told they couldn't do anything
unless they had the whole car, not just the carb. However, it was suggested
that I adjust the float to less than spec. The manual says to set the
float so that the low point of the U-shape in the float sits .020-.060"
below the level of the carb body (inverted at the time). It was
suggested that I make it higher so the needle valve just opens a
little and closes rather quickly. Only the center of the bottom plate
of the carb has to be wet, where it dips down below the jet intake (wow,
a jet intake on an MG!). Non-HIF owners may not visualize this too well but
it's a tough ASCII drawing and a glance at the pictures in the manual
should clarify this.
I'll try this tonight and will followup if successful.
-Dan
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