Triumph Repair: 76 spit idles but wont run, vacuum test, manifold vacuum

Question
problem: My 76 spit 1500 will start and idle around 500 and continue to idle but when given throttle via the pedal or the engine it will not rev up, it sounds like it may slightly but it isnt shown on the gauge.
description: the car dies when the choke is pulled. it ran before i took off and reinstalled the choke system connected to the carb to add in a missing screw because it was leaking gas and needed tightening.

Answer
Hi Sam,

If it ran ok before you worked on the choke system it makes sense to look at that first. Check the screw you put in first to see that it is not too long.

Even though that choke repair is likely where the problem is, if you find that the screw has nothing to do with the problem look at the diaphragm on the piston in the top of the carburetor to see that there is no holes or cracks in it. Then confirm that the piston is free and can move up and down.

If the car has a CAT in the exhaust, run a manifold vacuum test.
Note the vacuum at idle and what it is as you try to slowly open the throttle and tell me what the readings are.

Howard