electric choke - inconsistent RPMs when cold
gillmore
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- FORMER: 1979 Jeep CJ5 w/ stock 304 V8, T-150, Dana 20 transfer case, Dana 30 Front & AMC 20 rear, MC 2100 carb, 31x10.5x15 (8" wheels), no lift (HD leaf pack), Warn 8274 winch, ~99K miles.
I have a 79 CJ5 with the AMC 304 (CA emissions). The MC2100 has an electric choke and the heat riser tube is in place.
I've been experiencing inconsistent RPMs when the engine is cold (35-55 degrees ambient temp). Once started, sometimes the fast idle will go up to 1500 RPM, then step down normally as it warms up. Other times, it will only go to 1500 RPM for a second or two -- and then back down to 750-1000. Other times it will never go to 1500 until I've driven it a bit -- or wait (and wait) until it warms up while idling at 750-1000 (steps up to 1500 then steps down). It usually idles steady at whatever level it decides to pick.
My plan is to start by testing voltages at the choke thermostat (first thing in the morning). I'll also check for any sticking bits. Other than that, is there anything else I should be testing? How does one know when the choke thermostat needs replacing?
I've been experiencing inconsistent RPMs when the engine is cold (35-55 degrees ambient temp). Once started, sometimes the fast idle will go up to 1500 RPM, then step down normally as it warms up. Other times, it will only go to 1500 RPM for a second or two -- and then back down to 750-1000. Other times it will never go to 1500 until I've driven it a bit -- or wait (and wait) until it warms up while idling at 750-1000 (steps up to 1500 then steps down). It usually idles steady at whatever level it decides to pick.
My plan is to start by testing voltages at the choke thermostat (first thing in the morning). I'll also check for any sticking bits. Other than that, is there anything else I should be testing? How does one know when the choke thermostat needs replacing?