Hi all. Finally getting to my carb rebuild. Just started to break it down, taking lots of pictures.

Q1: There was a small metal tube and O-ring on the choke housing...



I removed the tube and O-ring and separated them. Then I turned over the choke to this side...



...and was fiddling with the inside to see how the parts moved and another little tube fell out onto the table. See both tubes below. The top one is the one that was in the O-ring, the lower one is the one that fell out. My question is where does the lower one go? If I had to guess I would say it was under the other tube. And which way should it go back in? One end has a smaller diam than the other.



Q2: For the secondary diaphragm housing, the Holley sheet says there should be a check ball (#20 below) in the housing, but I didn't see one. (The sheet has a disclaimer saying the diagrams may not be accurate.) Do you guys recall if there is supposed to be a check ball there on this 4180 carb?







Oh, by the way, I DID find metal filings in the secondary fuel bowl, probably from the self-threading fuel inlet fitting I had put in. (Thought I was real careful, but apparently not.) When I posted before about the stripped inlet threads and engine dying after using the self-tapping fitting, it was suggested that some filings may have gotten in and clogged up the needle valve. Really surprised there were so many filings.

 

I don't know where the little tube goes, but I will warn you, do not take this carb apart in a million pieces(I hope I am not too late). Just because it has a screw holding it on, doesn't mean you need to take it apart. For instance the choke housing; All you need to do is take it apart enough to replace any rubber parts. The choke housing doesn't need to be soaked in cleaner. Just take the carb apart enough where you can soak the main body and the metering block to clean all the small holes. Or just use a spray can to clean out all the little holes.

If you take too much stuff apart, you may never get it back together correctly.

 

Thanks for the advice, Dave. I'll follow that advice going forward. I've only done the choke and diaphragm and removed one fuel bowl so far. So hopefully it's not too late - if I can just figure out how to re-install the little tube that fell out.

 

On the little tube; Could it be the choke pull-off piston? That's what that cylinder and linkage thing is inside the chamber. Vacuum is applied through a passage and pulls on the piston, which slides in the bore and the linkage acts on the choke lever. When you set the choke on a cold morning by pushing the gas pedal, the choke spring shuts the choke door completely. When the engine first starts, it needs a little bit of air to run, the choke area is not hot yet, so they use vacuum from the engine to pull that piston forward and it hits the linkage and "cracks open" the choke door a little bit to give the engine some air to run.

There is a spec on how much it cracks the choke open. Not enough crack and the engine runs rich and tries to flood out. Too much crack and the engine stalls as soon as it starts, since it's getting too much air when it first gets going.

 

Hey Alan, how's the rebuild coming along?

1) Yes, on mine there was a check ball in the secondary diaphragm housing. I removed the check ball, cleaned out the passage, and re-installed the check ball. My secondaries work great.
2) The other device you were asking about is indeed the choke pull off. The little brass tubes didn't come out when I did mine so I'm not sure about yours. About all I can add is put it back together so it looks right and worst case the choke might not kick down when you goose the throttle, but at least the choke will still open when the spring heats up.

The only other thing I'll add is that I found my installation worked best with the secondaries set at fully closed, and not 3/4 of a turn open as the instructions suggest. FWIW, the carb that came off my rig had the secondaries set at zero and also the carb I got from the junk yard was set at zero. I couldn't get a good idle with the secondaries cracked open.

 

I used to set the Holley secondary stop screw by backing it off until they completely closed, then turning it just far enough in the throttle plates would make a slight "pop" as they cleared the bore. Some of the emission Holleys have idle mixture screws on the secondary side and if you are too far open on the plates you will get a lean condition. Too far open can also draw fuel from the secondary booster venturiis.

 

im rebuilding a 4180 carb- hope the number is correct , i took the squirter off and when i turned the carb over 2 barrings fell out -- not sure where the go? plz help

 

Under the screw that holds the squirter in. They are check *****, if one is larger, it goes in second.