engine reving up problem Options

[clerk2k]

Quick background: My '73 FI 914 2.0/4 engine seized up and I replaced it with another 2.0/4 engine that I had from my parts car that the body had rusted out. That engine was running fine when I pulled it about 10 years ago. I reused all the existing sensors on the top of the engine that died, that were working when it died. Just put in new dist. cap and rotor (had electronic ign. which I left in place), new spark plugs, replaced oil/filter, and adjusted the valves before putting in the engine. After getting the new (old) engine in, hooking it all up, except all air filter plumbing, the engine started right up.

Problem: After the engine idles for a few seconds, it revs up uncontrollably and I have to turn off the ignition to stop it. The throttle is closed and not even being moved. I'm at my wits end. I've tested everything I can think of and everything seems to be working. I've tried adjusting the timing (rotating distr., vacuum hose disconnected). This has an affect on the initial idle but it still revs up no matter how I adjust it. I can't actually do a proper timing adjustment since I can't get the engine to idle.

Does anyone have an idea of what may be wrong?

Thanks,

Clint