Carb question (1 Viewer)

[Unicroc404]

So I had a "carb guy" rebuild a carb for me and now my truck won't run.

Long story short idk what's going on but I did notice this doesn't seem to fully engage and open the butter fly. Anything clearly wrong with this?

 

[devo]

What I know; that is your secondary kicking open. It will open the rest of the way when vacuum is applied from your intake manifold.
You can search the secondary extensively here on MUD. It’s also in the carb section of your FSM.

 

[charliemeyer007]

Find a better carb guy or even better learn to do it yourself. There are good vids on youtube. Hunt around on this site and you will find good procedures and links. So make sure there is spark and that fuel is making it to the carb.

 

[igotta40]

You’re saying it doesn’t idle? Or it won’t even start?

 

[Unicroc404]

You’re saying it doesn’t idle? Or it won’t even start?

It'll start, but dies out without being choked.

 

[CruiserInProgress]

It'll start, but dies out without being choked.

You might want to check for vacuum leaks, ie. around the carb base, unattached vacuum hoses, etc.

 

[Pighead]

Is this the same problem you were having before you got the carb rebuilt?

 

[Grayscale]

That carb looks like it has been media blasted.

 

[charliemeyer007]

So when asking for help, it pays to think about the question if you want good answers. Starts and then runs poorly until it dies. With choke on it will run for a while.

Mine needs choke for a long while because I have a header, even though I built a fluid heat riser for the carb base.

If it runs with the choke then the mixture is lean. Adjust the mixture screw out a little at a time (say 1/8 turn) and give it time to affect the engine. Make sure you have clean filters both fuel and air, the valve lash is correct and the timing is on, plus the correct level in the float window.

 

[Unicroc404]

So when asking for help, it pays to think about the question if you want good answers. Starts and then runs poorly until it dies. With choke on it will run for a while.

Mine needs choke for a long while because I have a header, even though I built a fluid heat riser for the carb base.

If it runs with the choke then the mixture is lean. Adjust the mixture screw out a little at a time (say 1/8 turn) and give it time to affect the engine. Make sure you have clean filters both fuel and air, the valve lash is correct and the timing is on, plus the correct level in the float window.

Oh, well... see, another part of the issue is that adjusting it does essentially nothing lol

 

[charliemeyer007]

So I had a friend that was a hydraulic's guy - I think he was a parts salesman but maybe he made up hoses and stuff too. Anyway I loaned him my A-Frame and chainfals to work on his Ford 8N. He decided to work on his girl friends car Jeep YJ? Anyway he put in a carb kit. He couldn't get it to run unless it was almost wide open throttle. He fiddled with it for days. I went over to see haow the tractor work was going. He told me about the car issue. I grabbed a can of starter fluid and spayed the carb sections while GF cranked it over. It fired right up when I sprayed the joint between section 1 and 2 towards the base. Pulled the carb and he had placed a gasket backwards and some fitting inside wouldn't allow the sections to mate correctly - big vac leak!. Put it back together and it fired right up and ran smoothly - did need a little tweaking.

Moral of the story; some people are not good with small delicate parts - they could ruin an anvil with a rubber mallet. YMMV

 

[CruiserInProgress]

Oh, well... see, another part of the issue is that adjusting it does essentially nothing lol

A while back I had trouble getting my desmogged 79 running properly, lots of issues after sitting for many years.

Anyway, as part of the process I installed a shiny, new City Racer Fuji carb, to replace the PO's non-working Holley, thinking that alone might fix it.

After installing the new carb, it ran a bit rough and I couldn't get it to idle without at least some choke.

In the course of troubleshooting, thanks to help from IHMUD members, I found the following in my specific situation:

- My carb insulator had deformed over the years (compressed corners), creating vacuum leaks and necessitating the use of choke to idle. A straight edge confirmed it and a flat file fixed it.

- Not sure if my problems were related somehow to the new carb, I downloaded a FSM and painstakingly went through all the necessary internal and linkage adjustments to make sure.

- In my case there were several additional issues (bad fuel, clogged fuel lines, bad distributor cap, cobbled ignition wiring, etc.) that aren't relevant here, but made a huge difference.

Well, after all of that, it still has some hesitation that needs to be sorted out, but it now starts right up and for the first time in many years, I was able to drive it around a bit...what a blast, and very satisfying.

 

[Grayscale]

Was the carb treated in a Chem-Dip akin to Berryman? What is the history of the carb, did gas sit for months while it was not in service?

 

[pb4ugo]

If the idle mixture screws aren't working usully means fuel is bypassing the idle circuit. Make sure the throttle plates are fully closing. They might be hanging up on something. Sometimes a gasket can stick out a little into the bore where they close. The carb could be leaking fuel thru the venturies too.