Thanks to all who replied about my carb problem (re-quoted again, below.)
I have the Lucas pump, and it is pumping at exactly 3.5 PSI, so the
possible overpressure problem that a couple of you mentioned was not a
problem. Neither were the floats, as they were floating high without any
gasoline inside. It appears the rear needle/seat was the problem. Both
were adjusted just right at the 7/16 measurement as prescribed, but the
rear one must have been stuck.
I took it apart, inspected, cleaned, and re-assembled the float chamber.
There was a little bit of sediment in the bottom of the bowl, but nothing
noticeable in the seat. THe float moved very freely on the shaft, and
there were not any snags to hang up on. Started it up after assembly, and
it ran just fine. Took it out for a test spin, and about a mile down the
road, there it started again, but this time it was not intermittent. It
was pumping out a full flow from the rear float bowl overflow!
I took it apart again, stoned the outside of the float lever (in case it
was hanging up on the lid), checked the needle/seat again, and put things
back together. Started fine, and didn't flood. I didn't get to take it
for a test then, because it was lunch time. After lunch, I went to start
the engine, and when I turned the key, the pump was clicking away pumping
gas out the overflow.
Did it all again, but this time I swiveled the fill hoses around so they
were not pulling so snuggly against the float bowl. Voila! That seems to
cured things. I've driven it about 30 miles since, and tried to empty the
bowl (80MPH) and back off quickly to get it to stick, but no
problems...yet.
Meanwhile, while looking though the A-Antics book for some possible
solutions, I read about the Grose Jets as a sure cure for the sticking
needle. Moss catalog and another article seem to recommend them, as well,
so I ordered a set to give them a try. I also ordered the SU shop manual
and the carb adjusting kit that was the topic here last week.
So, I seem to be working now, and hope to get the replacements before the
weekend. If so, or even maybe if not, I can give it a try to get to
Perrysburg for Edwin's Lake Erie Car Show Sunday!
Thanks again for the help and suggestions,
Steve
>List,
>
>Coming home from Easton last week in Columbus, my MGA was missing on
>occasion. It felt like intermittent fuel starvation. I thought it was gas
>boiling in the bowls while I was in traffic, but it continued out on the
>open road.
>
>I haven't really started digging into the problem yet, but last night I
>was showing my Dad what it was doing, and I discovered a strange symptom.
>I started he car and it ran fine. After a while, when it warmed up, it
>suddenly slowed down and started stumbling. Then after a few seconds it
>would be OK, and then go through this again. Then I smelled gasoline.
>
>I looked at the overflows, and the rear one was squirting gas...then it
>wasn't...then it was, all timed to the stumbling of the engine. It would
>squirt for about 3 seconds, then run OK for about 8-10 seconds, then
>squirt for three over and over.
>
>I know about float adjustment, bad float needle seat, etc., but I can't
>think of anything that would cause this intermittent flooding. Oh, and
>when the key is on and the engine is not running, nothing squirts, and
>the pump is silent.
Steve Morris Avon, Ohio
1958 MGA 1500 Red/Black
NAMGAR #5987 BuckAyes Ohio Chapter
LoCo Brits <mailto: MGA1500@mac.com>
http://www.en.com/users/smorris/mga/
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