Ok long story short I use this motor on my 58 Thompson. Ran perfect first few times out except I had to splash carbs with gas on initial start up. Noticed it was missing a spring/linkage as the butterfly wasn’t closing when operating the hand or electric choke. After I installed the linkage spring it started running poorly. Needing full throttle to accomplish what would normally be 1/2 throttle. Changed plugs cleaned points and distributor cap but took it out today and same thing. Seemed to run a little better the 1st couple minutes after sitting a while but would gradually bog down. Can someone tell me with certainty that the spring is installed correctly? Seems strange this all started when I put the spring on. Also I checked spark at all cylinders and yes is good. Still seems to idle good after warmed up a couple minutes. Thanks