[tirwin]

Averitt,

The WUR is a device designed to replace the choke in prior engines that used carbs. It gives more fuel to richen the mixture on a cold start. That's when you need a rich mixture. The 12V electrical connection provides power to the WUR when the car is started. The current heats up an arm (the bimetallic strip) with a plunger at the end. When the engine is cold, that plunger sits low. The current heats up the two metals (the "bi" in "bimetallic"). Since the two metals are different they contract at different rates, just like when you flex your arm muscle. This causes the arm and the plunger to rise and close off a valve at the top of the WUR. When the valve closes off, the warm control pressure is raised to normal operating pressure (and as a result the mixture is leaned out to "normal"). The strip was designed so that the time it takes for the plunger arm to rise from the lowest point to the highest point is the amount of time needed to warm the engine. (Once the engine is warm, you don't need the richer mixture anymore, so the WUR has done it's job.) When the engine cools off, the arm in the WUR drops back to it's start position. One more thing. If the 12V connection to the WUR isn't working, then the control arm will rise but it will take longer because it has to get heated by the radiant heat coming off the engine.

What's happening in your case is that the arm isn't closing all the way which leads to an overly rich mixture, so on a warm start (when you don't need the richer mixture), you have a mixture that is too rich so you're flooding the cylinders with too much fuel, making the car hard to start. The procedure ossiblue described will adjust the starting point of the travel of the plunger arm so that your warm control pressure is correct. If you do that, I'll bet your problem will be solved.

The best way to get the AFR set is with an exhaust gas analyzer. Get the WCP sorted out first though. You definitely don't want to mess with AFR before you get that resolved.