Hello All,
I'm new to this group - looking for any information or pointers about MGs.
I recently purchased a 1973 MGB Roadster (my first MG, I'll try not to ask
too many silly questions). I've cleaned it all up physically, and sorted out
various wiring problems, but I'm currently stuck on an engine problem....
I didn't know that it was possible for a 4-stroke engine to run on only one
cylinder, but that is what this one is doing.....
After cleaning everything up and making sure I had fuel, I tried to start
the car - after much cranking it started to catch a little bit, and eventually
would run with the choke full-on (with some irregular misfiring and backfiring
through the carburetors).
At this point, I tried to eliminate problems in the ignition system, I replaced
the distributor cap, rotor, plugs, and plug wires. I set the dwell for 60
degrees as specified, and performed the static timing ritual. No change in
the symptoms. The way that I know it is running on #2 only - I removed all
plug wires except for #2 and had no change in the running. If I leave
1, 3, and 4 connected and disconnect #2 it will not run at all.
So what is the problem? I don't have any history on this vehicle - it looks
like someone else tried (unsuccesfully) to get it running, but I have tried to
clean up all of their messes and make everything as simple as possible.
I have the plugs wired up 1-3-4-2 firing order, with #1 at the position
immediately to the right of the key on the distributor cap, and counting
in the counterclockwise direction. My compression tests out at
110, 115, 115, 120 (it is supposed to be 120 for a low compression engine,
right?). I am obviously getting spark, I even got a nasty shock from 1,3,4
when I was removing them while running on #2. I could have carburetor
problems, but since 1&2 seem to run on one carb and 3&4 seem to run on the
other, I would expect #1 to be working at least somewhat if #2 is working.
Does anyone have any ideas what I might look at next? Like I said, I am new
to MGs and may have made some silly mistakes, and this car has been worked on
by unknown parties and was not running when I purchased it (could have had
almost anything done to it........).
Thanks!
Jon Swanson
swanson@zonker.ecs.umass.edu
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