Hello and welcome to jeepz.com. Since your temp gauge isn't working was just wondering if your fuel gauge was . They work as a pair on the CJ and should be replaced as a pair as well. That sometimes presents problems with the fuel tank sending unit in terms of compatability for accurate ( or close at best) readings . But you'll want to know engine temp at all times regardless of any issues . You'll have to determine if the engine is running too hot for obvious reasons . Be sure the usual,items like radiator hoses not collapsing , water pump circulation , thermostat operation , heater core circulation or any restrictions are a cause.
Of you find the cooling system is in order or get it in to shape and it's all good then it's time to check the fuel and emissions system. Check if the fuel line from the tank isn't getting neat soaked from being to close to exhaust or the fuel line from fuel pump which may have been rerouted to accommodate the motorcraft carb isn't suffering the same. Check that all vacuum lines are correctly routed since the carb has been fitted to this engine , especially evap.lines . If a canister purge line is feeding the engine cold with no thermal switch for example it will run rich and continue to do so when engine is warm and idle will suffer over rich condition. Cold engine on fast idle will be less noticed . A thermal,vacuum switch ( TVS) or coolant temperature override ( CTO) are supposed to prevent things like this. It's possible that items such as these have been installed incorrectly since the carb may differ from the original configuration so it's best to sort this out and be sure. Float bowl vents vent TO the canister purge and fuel vapor should be introduced to the engine when warm via the vacuum switches previously mentioned usually to a throttle plate port and the switch controlled by engine vacuum ABOVE idle . That vacuum signal comes from the float bowl ( upper) part of the carb . Usually a signal port on the rear of the carb operates this bit sort this out with a manual that best illustrates the model carb to correctly route all vacuum lines that exist .
Another possibility that may be likely is the carburetor itself. The motorcraft has a power valve just as a Holley carb has but of different design but does,the same job. Of this valve fails , the result is an over rich condition , flooding , stalling whether idling or accelerating . youll want to check your spark plugs to see if there are tell tale signs . Of the porcelain is whitish or burned looking ( running hot or too lean ) wet or carbonated ( over rich condition) . You may want to be sure the choke is working right and not sticking partially closed with fast idle off. Does the exhaust have a heat riser valve ? Is it opening fully when warm ? Hopefully you don't have a sinking carburetor float causing a over rich condition cold or warm .
How about the ignition system ? You'll want to be sure the ignition wires are primo as well the cap and rotor.
These are some items of the top of my head but even items such as a fuel filter shouldn't be overlooked. A fuel restriction can be troublesome and cause similar symptoms . Usually fuel,restrictions are noticeable cold or hot engine but good to be sure .
Hope this helps but at least is a good start . Check these items and let us know what you find . Post back when you can . Thank you for your membership .
