Truck won't idle down out of the blue?

Trapping rig won't stay running if I let off of the gas just poof dash lights come on? Had to move the idle screw all the way up and shorten the accelerator cable to keep it from dying when I let up on the gas. Busy time for me now so I can't deep dive into it. I checked the distributor vacuum line moved the distributor around, checked plug wires but no luck any ideas would be great.

Auto choke still working? If you see thick, brown grease on the end of the wax pellet actuator rod, it's dead. Other than that, check for the usual vacuum leaks. And the not so usual (like the diaphragm in the auto choke release assist - they do perish and fail and I have replaced a couple when meddling with the Mikuni) Also check the fuel cut solenoid on the side of the carb (if it doesn't kick when you unplug it and plug it back in with the ignition on, it has issues) and possible fuel blockages/dirty jets etc.

Running a Weber on it will try to get into it today and see what I can find.
Thanks

O.k. my mistake. Everyone has issues with the Mikuni so I assumed this was your deal too. This should be an easy fault to diagnose on the Weber.

Well today I had to turn the idle down hope to get into it tomorrow just can't get a hour to even look at it I'm so busy!

Attachment 19949Found a bad casting on the Weber adapter plate that allowed for a air leak, new gaskets and all is good so far.

Get a sheet of 400 grit wet and dry, wet it and stick it up against a window and use it to reface the adapter plate. I've had to do that to the throttle butterfly plates on Mikuni carbs when they go funky. It's not super perfect but it is more than adequate when you're installing new paper gaskets.

I added a thicker gasket and put some Permatex on the bad side of the plate until I get another one ordered from Redline. Was going to add a thicker spacer to the Weber but the studs were too short did not want to pull the threads. I will add the spacer when I get the new plate and call it a "highrise" then. LOL

spraying carburetor cleaner around intake/carb bolt on location will help find any other possible leaks.

Thanks!