Bob,
I'm running a single H4 carb on my 1275 with a custom manifold and it
doesn't have that problem. The PO was very careful when he designed the
manifold to insure that the float bowl would be at the correct angle. They
are designed to be mounted at a particular angle (which escapes me). Does
your manifold result in a float bowl that is level to the ground when the
car is level, or is it angled slightly?
Regards,
Glen Byrns
'59 bugeye
'59 Morris Traveller (Winifred)
> Seeking wisdom here -
>
> Car is a '74 Midget, totally stock 1275 engine, 79,000 miles, desmogged,
> with intake and header mods as outlined in David Vizard's book. I took
off
> the old intake manifold and dual carbs, and ordered an Oselli intake
> manifold from England and mated it to a single SU H4 (brand new, left over
> from a previous MGB project), K&N air filter, and also added a header from
> APT. Once I got the needle set up right, the difference in power is
> amazing. I haven't run a dyno or anything, but my rump-o-meter tells me
> that if I had 55-60hp before, I probably have 75+ now, huge difference,
much
> more fun to drive, really zips along. However, and there is always a
> however, when I really hit the brakes, the engine stalls. When I first
> swapped over, if I even thought about the brakes, it stalled, and my
> euphoria over the increased power was quickly tempered with an "oh no, now
> what do I do?" I asked the local LBC folks, but nobody seemed to know
> anything beyond the original dual carb set up, they thought I was crazy
for
> trying a single 1.5" SU. But after enjoying a Midget that can breathe
> properly, I'm never going back to the original twin SU set up. So I asked
> Joe Curdo up in New York and his advice was reset the float level. I set
it
> at the prescribed height and it helped a little bit. I then reset it as
> high as I could and it just about solved it, but then I had gas leaking
out
> the seal, on to the hot exhaust manifold. So I lowered the float just
> enough so I don't have gas leaking out the seal, and it only stalls when I
> brake hard. I thought it might be that the carb might be bad, and since I
> have two new H4s (for the MGB), I tried them both, each with the same
> result. Any thoughts??
>
> Bob (aka grasshopper on this one)
> '74 MG Midget (very quick, but stalls from time to time)
> '90 944S2 Cab
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