jhs2053

I noticed nobody's answered this after several days, so I'll offer one suggestion. Assuming that you've checked the choke to make sure it's opening fully when hot and that the engine runs well except for the fast idle, you may have an anti-dieseling solenoid that's just re-awakened. It's the octagonal part sticking out of the left front of the Hitachi carb with one wire attached. The solenoid normally shuts off the fuel supply through the slow idle passage if it doesn't get current through the wire, meaning that the engine won't idle when the circuit is interrupted. Many shade tree mechanics deal with this by simply turning up the idle screw until the engine idles on the main jet and get acceptable performance (a little less stable idle and some dieseling when you shut the car off). However, if the solenoid starts working again, the hot idle goes up about 1,000 rpm. You might want to check the wiring to the solenoid to make sure there aren't any breaks or funky connections that might have suddenly started working again. If everything looks OK, try turning the idle adjusting screw back a lot (probably about 2-2 1/2 turns) and see what happens. If it solves the problem, don't leave home without a screwdriver until you're sure the solenoid is trustworthy.