Oh great knowledge base...
I'm having what I suspect are carburetor problems and wanted to bounce the
symptoms off the list to see if my reasoning is correct and to hopefully get
some ideas about what I may be missing. Sorry for the length of this post.
I've static timed, set the point gap, replaced plugs , distributor, rotor, plug
wires, low tension lead and added a Lucas Sport coil. Have disassembled and
cleaned the carbs (SU HS6) - pretty routine tune-up stuff.
None of this resolved the problem. The car responds well to tuning while at idle
before and after the work described above. I drive down the road about 2 miles
winding it through the gears and having fun. It runs absolutely fantastic then
starts missing/sputtering until I have no power and must turn around and come
home. Inspection of the spark plugs reveals cylinders 1 and 2 are fuel fouled
(dry black) while 3 and 4 are medium tan. I been through five iterations of this
- cleaning the plugs after each run and tuning again.
I have adjusted the mixture many times and get the proper short rise in idle
speed and settling down on both carbs when lifting the piston. I suspect the
front carb float misbehaving but can't seem to verify this. I use the carb
cleaner trick on the throttle shafts and can't conclusively determine if there
is a vacuum leak though by hand the shafts can be wiggled slightly. Both front
and rear carbs have a similar slight amount of play in the throttle shafts.
This all occurred after the car sat for 9 months of shipwrights disease. There
was only 1/2 gallon of gas in it and it was not treated/stabilized so I
suspected I'd gummed the works. This gas should have been worked out by now and
it has fresh premium in it. All fuel lines have been cleaned or replaced and a
new fuel filter installed. When I cleaned the carbs they were quite dirty -
especially the front float bowl. It ran fine 9 months ago. It has Grose jets for
float valves.
Any ideas?
Thanks,
Mark A. Evans
1966 TR4A IRS CTC63970 LO
markaevans@mindspring.com
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