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You mean when you rev it above 3000 rpm it starts to die, but then if you pump the pedal it will keep running long enough to drop back to idle?
That sounds more like carb trouble than fuel pump trouble (although you could splice a fuel pressure gauge in just ahead of the carb to see for sure whether the pump is pumping or not.)
After all, the fuel pump's only job is to keep the carb float bowl full. Your float bowl must be pretty full if there's still enough in it to squirt out via the accelerator pump when you pump the pedal. How about if you run it up to 3000 and let it die, then take the top off the carb and check the fuel level? Or just give the throttle linkage a yank and see if fuel squirts out the accel-pump outlet. If there's fuel in the bowl and/or if the pump is still squirting, then the fuel pump isn't a likely suspect, right?
If you're feeling really gonzo, you might rig up a simple gravity-feed fuel supply by hanging a container above and running a fuel line down to the carb... this would take the fuel pump out of the equation completely and let you see whether the engine still behaves the same or not. (Remember to disconnect the electric pump and plug the regular fuel line before testing, so fuel doesn't leak out!)
Since this is a new carb installation, the first thing I'd suspect is a partly clogged main jet. It might deliver enough fuel to run the engine up to a certain point, but above that the fuel would starve out. Idling wouldn't be affected because fuel at idle is supplied through a separate jet.
Speaking of which, do you know what main jet you got with your carb? If you bought it from one of the vintage-SAAB specialists it's probably OK, but if you just bought a generic 34ICH there's no telling what jet size you got. I don't have my 34ICH anymore, but as I recall it came with a 165 jet, which was mostly OK, but eventually I went up to a 175 to get rid of some 'lean surge' at highway speeds. The size number should be stamped on the jet. If yours is too small you may need to upsize it.
I'm not a carb expert, just trying to troubleshoot this in a logical way.
posted by 68.13.13...
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