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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