help diagnose these symptoms

[NickDawson]

update:
The new MC arrived already bench bleed - suspect someone at our hosts took pity on me... but I repeated the process to learn...
Its installed - the old one was definitely toast. Still waiting on some breaklines from our hosts to complete the job.

I also installed a new thermostat and gasket - fingers crossed thats where the coolant on the block was coming from.

Then I turned my attention to the carb... for the life of me I cannot get the damn thing off the intake...I'm sure with some more time and patience it will come, but I'm going to take Kevkon's advice and check the timing before I do anything else. ... although timing still doesnt answer why the idle problem started after running fine for 4 weeks.

If it comes down to it, I've heard that you can turn an old carb in for a partial exchange on a newly rebuilt one - do our hosts offer that? I'm determined not to "buy my way out" of the problem...but if push comes to shove, I'd rather drive again this summer than tinker for 4 weeks.

[NickDawson]

Fingers crossed that its a timing issue...

I got the carb off and cleaned it every what I could find... if there was a screw, I unscrewed it, if there was a hole, it got sprayed...if there was a valve it got enough cleaner to light up a bonfire.

Admittedly I was surprised that the truck ran again once I put it back together... it might actually be running better, but the cable that connects the throttle linkage to the throttle on the carb seems to be getting stuck a little open. Maybe I cleaned it too much! Anyone know the best way to lubricate that throttle and cable?

Back to timing and Kevkon's point - could inaccurate timing cause my backfire and occasional dieseling? Could timing cause it to run rich (or similar symptoms)?

Still awaiting the break lines from RN - hope they account for the different size orifice on the new MC and the old break lines

[kevkon]

Nick, improper valve or ignition timing will cause the combustion sequence to become out of sync. If the spark or ignition occurs too early ( advanced) or too late (retarded) then the fuel mixture will not yield it's optimum potential energy. Also too much advance will cause ignition to occur before the valves are closed causing the backfire. One advantage to using a timing light is that you can observe any fluctuations in the timing which may indicate a vacuum leak or a problem with the timing chain or valve train.
As for the cable lube, I like to use the motorcycle cable lube products such as Tr-Flow.