First carb rebuild...hard earned success (1 Viewer)

[Gretsch]

And if it seems to be the EC is faulty (because as @Pin_Head said grounding it DOES enable the FCS to work) , I began this thread awhile back on reflowing the solder points which may be cracked... Reflowing Solder Points

I ended up reflowing mine. Worried I was going to mess it up and have to find a new EC but it worked out and has been rock solid since.

 

[FJ Noob]

Never run through this procedure myself but seemed to be plausible when I viewed it. Maybe others can chime in as to if this works well or not. Sounds like you are getting her pretty well dialed in now so might not be useful but thought I would add in case it is. Sorry for the distractions here. Carry on.

I looked at that as it is essentially what the FSM describes. I'm just not getting any change when I adjust the mixture screw. I can get it running and idle fine, but not reliably below about 1050rpm.

I ran over to my other truck and pulled its carb while I was getting a door and fender to restore. I planned on rebuilding it anyway, so I'll go ahead and knock that out and see if there's a difference when I put it on the main truck. Maybe that'll help determine a carb specific issue or not.

Might as well check the board too since it sounds like it's very accessible.

 

[FJACS]

High idle with limited adjustability is almost always a vacuum leak. A vacuum leak can be as easy as the hoses, or more complicated like gasket leaks, fitting leaks or internal carb leaks.

Sorry if you’ve already discussed this elsewhere - but I see you labeled the vac lines to presumably return them to the correct locations. Did you at any point use the Emissions FSM to ensure they were routed correctly to begin with?

 

[FJ Noob]

High idle with limited adjustability is almost always a vacuum leak. A vacuum leak can be as easy as the hoses, or more complicated like gasket leaks, fitting leaks or internal carb leaks.

Sorry if you’ve already discussed this elsewhere - but I see you labeled the vac lines to presumably return them to the correct locations. Did you at any point use the Emissions FSM to ensure they were routed correctly to begin with?

I can get it to run just about like it was when I picked it up...idle around 1000. I knew that wasn't right, but was waiting to rebuild the carb to go after that. I honestly didn't check the FSM because it was working. I have come to the conclusion that I need to do that.

I've squirted around all the vac lines with carb cleaner and it doesn't seem like I have a leak there. The main rubber gasket between the air horn and air cleaner is as hard as a rock and not fitting well. I grabbed a newer pliable one today that I'll throw on. Most likely not my issue, but it should help cut out 1 little leak that might be compounding with other things.

 

[NeverGiveUpYota]

Someone can correct me if I’m wrong but more often vacuum leaks are below the carb.

 

[WSOPgold2012]

I went thru 4 different carbs before finally throwing in the towel and doing a Sniper EFI conversion....do yourself a favor and convert!!!

 

[FJACS]

Spraying around the base of the carb to check for leaks is a good start - when you pulled the carb off did you lift the carb insulator off? IIRC there is no gasket between the intake and the insulator. You might want to use some fuel safe sealant (permatex makes one) and ensure the insulator is sealed to the intake. Also check that the pipe the PCV hose connects to is secure into the carb insulator- these can come loose. If it’s loose, glue it back in with the permatex goop.

 

[NeverGiveUpYota]

If it’s loose, glue it back in with the permatex goop.

Similarly JB weld works if you mix it and let it set up so it’s a bit thicker before applying. Scrap any loose stock epoxy off first and as you apply the JB weld try to jiggle the insulator so the weld settles in any crevices.

 

[John McVicker]

I had the same issue. If you have not verified that your carb insulator is in good shape, take it off and inspect the bottom. It was my problem and was forever solved for $99.

 

[FJ Noob]

- when you pulled the carb off did you lift the carb insulator off?.... If it’s loose, glue it back in with the permatex goop.

Similarly JB weld works if you mix it and let it set up so it’s a bit thicker before applying. Scrap any loose stock epoxy off first and as you apply the JB weld try to jiggle the insulator so the weld settles in any crevices.

I did not pull the insulator off, but compared to the other truck I pulled a carb off of today, this truck's insulator seemed loose...like there is nothing and never has been anything between it and the intake.

Does it "simply" lift off or is there some hidden bolt holding it elsewhere?

 

[FJ Noob]

I had the same issue. If you have not verified that your carb insulator is in good shape, take it off and inspect the bottom. It was my problem and was forever solved for $99.

1) Thanks for the pic to help ID what I'm looking for.
2) What site is that...vintageteqparts.com? City Racer...found it.
3) Awesome choice of avatar pic

 

[John McVicker]

Remove the carb, then take 2 or 3 12m bolts off and the insulator will lift right up.


EDIT: Yes, you are correct, City Racer.

2nd EDIT: Thanks on the avatar. I love that pic of ‘Chesty’.

 

[FJ Noob]

Pulled the EC board...doesn’t look too bad except for the few spots that are slightly darker. They mostly seem to be the ones for the actual connector. Probably still need to re-flow?

 

[Gretsch]

I am not sure I would mess with it unless you know the FCS is causing an issue. The plug is usually where the solder breaks though. You can put it all back, and simply bypass the EC by taking the ground lead coming from the solenoid itself and grounding it to the carb. @Pin_Head alluded to this earlier today. Would start by making sure with the engine off, and ignition switch on you hear a click from the FCS when plugging and un-plugging the connector. If you do then you know the Solenoid itself works. Now on mine it would click all the time and yet not allow the truck to idle. So a sure test is to bypass the EC by grounding directly to the carb, then start the truck, and try and lower the idle speed to the 700 RPM range. If it idles then you may have found your issue. I only reflowed mine after confirming it was a bad ground causing my FCS to not work. I would not try this if you don't need to. Last time I checked these EC boards were sort of difficult to find and expensive if you do.

Having said all this I would lean more to this being an issue with the vacuum as suggested. Its possible someone ran into this issue and the FCS system is actually broken somehow, and to get around it they set the idle higher. But I would lean towards what others are saying with the vacuum setup. Do you have a vacuum gauge?

 

[FJ Noob]

I am not sure I would mess with it unless you know the FCS is causing an issue.

Ok, thanks @Robert Franzke ... I do get the "click" with a basic test. I was saving @Pin_Head 's suggestion for if I needed to work up the ladder from easy to hard (e.g. mechanical to electrical).

I think we may have a winner though...at least a major contributor. I just went out and sprayed carb cleaner down low at the manifold to insulator connection. There was a definite change in the running of the engine. Actually sounded like the rpms went down instead of up, but either way...there was a major change.

Thanks @FJACS @NeverGiveUpYota and @John McVicker for bringing that up.

 

[g-man]

I rebuilt my carb once and when I put it on the truck, I couldn't get it to idle w/out pulling the choke out or rev'ing the engine. I pulled it back off and went thru the FSM step by step and realized I had missed installing a small piece in the upper section which caused and internal vacuum leak. That's why I recommend going by the steps in the FSM carefully checking off each one so you don't skip something.

 

[FJ Noob]

That's why I recommend going by the steps in the FSM carefully checking off each one so you don't skip something.

Yep; had the FSM open, youtube up for visual help, and color diagram from carb rebuild kit. Pretty sure I got it all (no extra pieces left over), but I'm rebuilding another one today and I'll double-check again through the process.

HOWEVER - I finally had some time to get back to it this morning and I pulled the insulator. I was so focused on the carb itself before that I missed....

The fact that half of the sheet metal has been ripped off. Also had the section of insulator around the tubing just crumble in my hand.

Even without that, the insulator to manifold mating surface wasn't looking like it was getting a great seal.

Can't imagine any of this was helping my efforts. The more stuff I find like this, the more the second truck purchase seems like a great decision! Off to grab an insulator....

 

[FJ Noob]

Grabbed the insulator plate from the other truck (also broken on the same part of the sheet metal; is this a thing?) and the insulator checked out. Cleaned it up and rebuilt the carb from that truck; was going to do it anyway. Put all of it on the manifold, verified vacuum routes, and reconnected all lines.

Nailed it...

Adjusting the carb only took about 10-15 min and now she just quietly purrs.

I think I’ll try doing some editing on this thread later to make it useful for someone searching carb issues.

Thanks again to all those that offered suggestions, recommendations, and advice! Your help was invaluable.

 

[NeverGiveUpYota]

They all break in that same area.

 

[John McVicker]

Good job @FJ Noob !