Hey I just recently had some work done on my 81 K5 blazer. It sat for 6 years and just had the money to get the engine work needed to run. Had the engine took apart and cleaned and put back together. New gaskets as in head gaskets, and everthing from the heads up got new gaskets. Also got a new timing chain and the sprocket. Brand new radiator, tranny was flushed, new wires, plugs, distributor cap and rotar. I picked it up from the shop on December 3th 2011. And it was having a major problem, it would idle fine. But you put it in gear it would literally just die. The mechaninc told me it was most likely old fuel because it had sat for so long. So I drove it from the 3th until the night of the 5th. Still it had not changed a thing. Even tried all that carb cleaner and everthing. So then I had enough. I spent all this money and it ran like junk. I then took it to my friend, who works for a chevy dealer. He looked and told me it was my carb messed up. The floats were bad and it was just old. Just an old quadro-jet. So I bought a new 1406 Edelbrock Carb with electric choke. And now it seems to idle fine. But when it warms up and the choke plate on top the carb opens all the way and you give it some gas either in park or in gear it will pop. Kinda like a back fire. But only if your at a dead idle and stomp on it. It wont to it if you just ease on the throttle to a full throttle. And also it kinda seems not to have any power when im first starting out. Barely will even go up a hill. I am kinda burnt out on this and lost on what to do. It has alot of sentimental value to me. It was my fathers and he passed away in 2004. Im a young guy just trying to fix this old truck up. Any ideas on what I can do just do get it running good so I can drive it back and forth to work every week. Its a 160 mile drive one way just once a week. Just need this until I save up some money for new engine. If you have any answers the best way to get ahold of me is to call. I could really use the help thanks. 307-679-1919 Trevor

 

sounds to me like either timing or your carb isn't adjusted right. more so timing then fuel. i would grab a timing light and set it to 8 degrees advanced at idle and see what that does for you.

 

Okay so I just did that this morning. The carb is still popping. I can set the electric choke to where its almost fully closed on top the carb and the thing will run like a beast when you get on it. But then you open up the flap and it will pop like crazy. I have done a little research and there are alot of issues with this carb im guessing. Its brand new maybe could it be running lean? And how to I fix this

 

It does sound like you arent getting enough fuel. Have you changed the fuel filter?

 

I'm with blue. It sounds like a timing issue. If the base timing is correct (with the vacuum advance disconnected & the vacuum line plugged), then you may have a problem with the vacuum advance and/or mechanical advance.

After I installed an HEI distributor in my K5, I had a similar (but not as harsh) issue. I ended up rebuilding the distributor with a new vacuum advance and new bushings, springs, & weights for the mechanical advance and now it runs excellent.