Originally Posted by
geezer101
If you have the stock carb, the mechanical fuel pump is fine. Are the secondaries opening? This sounds a lot like a dead secondary vac actuator - no power under throttle and nothing from midrange upwards. If the diaphragm in it is split, it won't open the secondary throat and will also create a vac leak. Remove the air filter, disconnect the small elbow vacuum hose on the secondary solenoid and attach a longer hose to the solenoid, then suck on the other end of the hose. If you can pull air through it continuously, it has failed. It can be replaced without removing the carb but it takes a bit of manipulation.
I don't 'think' it's the fuel pump - it would drive fine until you got it onto open throttle and then it would struggle. I don't think it's a distributor fault but it could also have a bad vac advance (use the same method as the secondary fault diagnosis) which would nerf ignition advance (subsequent lack of power but would still have full rev range).
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