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1978 Town Coupe Rough Idle

Hello Bill,

Thank you for your endless patience for the woes of the Lincoln. My dad gave me the old 1978 Continental with the 7.5. l have tried everything we could think of to get it to idle smooth. It does have a re manufactured carb, just replaced the EGR valve, it has new spark plugs, wires, and coil. Dad was thinking we needed to set the float on the carb or that the Jets could be plugged, do you have any ideas?



Greetings Christian -

A 78 Lincoln Coupe with the 460 cid engine is a very nice automobile and capable of satisfying a Lincoln lovers needs in all respects.

Not knowing the history of your Lincoln or how long it has been sitting or how well it ran before you received it I can only offer the following basic suggestions. If you suspect that the jets could be plugged ( with fuel tank debris ) you could replace the fuel filter and then thoroughly inspect the old filter. Vehicles that have been unused for a period of time can in some cases form rust in the gas tank that will end up in the carburetor eventually. I am assuming that your new spark plugs and wiring are in good order but further ignition problems such as distributor cap and rotor or any of the electronic modules could also be considered as suspects.

If you are not capable of specific diagnosis, a trip to a trusted tune up shop near your location could prove less costly than guessing and replacing parts that are not faulty. A good capable tune up technician can electronically scope your engine and possibly identify electronic ignition problems or dead cylinders etc. A cylinder compression test may even be required. As these tests are performed, a good technician is led methodically to the problem area.

Even though the engine has had a remanufactured carburetor at some point in time, they are well known to disappoint especially if they are receiving rust laden fuel from the fuel tank, therefore I would begin with a fuel system inspection as you also seem to suspect with your plugged jets comment. If you have no success in the fuel area you could then move on to some of the other suggestions above if required. Good luck with a speedy repair and as usual we will stand by with any repair parts that you may require.