Triumph Repair: TR6 missing when cold, john deer tractor, vacuum advance

Question
Hi Howard
I have a '70 TR6PI which starts fine and idles in the usual way, however, when cold it misses under acceleration/load. This miss clears when the engine warms up usually after 5-10 mins then operates normally. I have renewed all electics and comfortable its nothing electrical but I could be wrong! any help to cure this frustrating problem appreciated.

Answer
Hi Les,
It is often difficult to tell if a miss under load is electrical or fuel related.
If your car came to me in a shop I would have to first do a valve adjustment and then a compression test. I would then clean or replace the spark plugs. Clean and adjust the points and check the resistance on the plug wires (if they are carbon) and examine the cap and rotor for carbon tracks. Then adjust the timing and check the vacuum advance unit and be sure the centrifugal advance is operating. Then check fuel pressure and warm the engine up and set the idle and check the oil in the top pots and lift the spring loaded pin under the edge of the top pot. If the engine dropped off and run like an old John Deer tractor I would check the other carburetor and do the same.
If any of this is not correct it needs to be corrected. Let me know if you need help on any one of the items. Don't skip any because you think it may be ok.
Howard