Somebody help a newbie!

[DumperSquarebody]

My truck is running rough. I’m chasing down vacuum leaks, trying to set initial timing, messing with air fuel mixture screws on the Quadrajet has no effect, going to pull the spark plugs and inspect those…. I’m hoping somebody can share some threads to just point me in the right direction of how to go about getting this truck running as good as a old 305 can without completely tearing into it. I have a coworker who is giving me a 350 that I’d like to build right but I’m not sure how long it’ll be until I’m able to swap that in so just want to have my 305 running hood enough to run to the dump once in awhile. Any help is greatly appreciated. Video of truck running

 

[89Suburban]

My truck is running rough. I’m chasing down vacuum leaks, trying to set initial timing, messing with air fuel mixture screws on the Quadrajet has no effect, going to pull the spark plugs and inspect those…. I’m hoping somebody can share some threads to just point me in the right direction of how to go about getting this truck running as good as a old 305 can without completely tearing into it. I have a coworker who is giving me a 350 that I’d like to build right but I’m not sure how long it’ll be until I’m able to swap that in so just want to have my 305 running hood enough to run to the dump once in awhile. Any help is greatly appreciated. Video of truck running

Welcome neighbor! I am east of you in King of Prussia/Valley Forge.

 

[DumperSquarebody]

Nice! Bought this truck in Williamsport area and drove it to Lancaster. I’ve wanted a square body for so long and with two kids and a third on the way, it was a tough sell to my wife at the current moment haha! But it’s got a dump bed and with the yard work our house needs she could see that it would enable her to dump yard waste easily and my dreams came true. Glad I’m in the squarebody club!

 

[mtbadbob]

Check to make sure you don't have a cracked spark plug

 

[DumperSquarebody]

Thanks Bob. I’ll do that

 

[Matt69olds]

Start with the basics. Inspect or replace the plugs, carefully inspect the plug wires. If they are in bad shape, replace them. Same with the distributor cap and rotor.

Once you’re certain the ignition system is in good shape, make sure the timing is right. There should be a sticker under the hood that outlines the procedure for setting the timing. Follow the procedure, set the timing to spec, then move onto the carb.

With the engine cold, remove the air cleaner lid. Push the throttle to the floor, the choke flap should close fully. Start the engine, once it’s running the choke flap should immediately open just a little. As the engine warms, the choke should slowly open. If not, find out why. There are tons of YouTube videos that can show you far better than I can explain.

Unfortunately, these trucks usually suffer from people who have no business being under the hood. Be prepared to have to fix whatever the previous owner screwed up trying to “fix” a problem.

 

[newguy11]

I’m with matt69olds on this one.
Slow and steady wins this race.
Check the firing order, make sure the wires are seated and not burned cracked or otherwise damaged. Then check the plugs. They will tell you a story about the engine. Once those things are squared away adjust the timing and a/f mix.
I think you’ll find that that’ll help a ton.

Fwiw I rebuilt my quadrajet earlier this year and it was an entirely different feeling engine after that

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[MarineOne]

I vote rebuild the carb. Q jets can leak internally. But to help diagnose.

What distributor is in it? I've had many be junk out of the box. How old/ what does coil ohm at?
Check spark plugs and wires for damage /what plugs are in it proper heat range is important.
Finally I'd do a leak down / compression test on each cylinder to get an idea on engine health
How old is fuel pump?
How long has truck been sitting if at all?

Check oil if it smells like fuel that would point to a carb issue aswell

 

[justhorns]

I’d do the compression test first! If it’s bad, save your money. You can look at the plugs too and get a good picture before buying any parts

 

[Snoots]

If your a/f mixture screws have no effect, the problem lies in the idle circuit being lean.
If you are going to rebuild it, get a kit from Cliff Ruggles. You'll be glad you did.

 

[DumperSquarebody]

Thanks again to everyone here helping me out. I had recently rebuilt the carb and did notice the difference. It ran much smoother but it was smelling very rich from exhaust. I just put a new distributor in it, I think it was an ax delco but I could be mistaken. The rotor button on the old one was completely ground off. The rotor itself look newer and I cleaned it up bc the spring tab that the button presses against still had good pressure. The spark plug wires were put on incorrectly from previous owner so I fixed that. I’ve been told that I may have a dead cylinder and I should pull the valve covers and take a look at the valves/rockers. I’m going to hold off on that until I take care of some “easier” things. Planning on changing spark plugs today and then running it and inspecting those and doing a few of the things listed here. I’ll report back. Thanks again everyone