my 1980 Pacer with a Morini M1 won't fire below 1/3 throttle. The carb is totally clean, the condenser was just replaced, and the whole thing has only 105 original miles... so to recap: I have excellent compression, good spark at all rpm's, and gas flow to a clean carb, but the thing won't stay running unless the throttle is at least 1/3 open. The throttle cable has proper tension and it is not the idle screw. Above 1/3 throttle is runs so well I just don't get it. The only thing I can think of is maybe something is blocking the transfer ports? I don't know, HELP!