Carburetor assembly question

[montanafordman]

Hello everyone - A question for you carburetor guys... I'm putting together a Zenith carb I've been going though and was curious if/what you put on the threads of the jets, fittings, and butterfly valve screws if anything?

I was thinking blue Loctite would be a good idea on the butterfly screws to keep them from vibrating loose and getting sucked someplace they shouldn't be yet able to disassemble later if necessary.

What about the filter screen threads, jet threads etc.? I would be concerned with anything you use could potentially clog something especially if you put a little too much on it but a little lube might not be a bad idea either to keep things from corroding or getting stuck. Would you consider a slight bit of grease or anti seize for any of these other threads? or just run em in with a squirt of spray lube like WD40 or run them in dry? Thanks for your input.

[Joe K]

The butterfly screws with loctite is a must.

But those rest - most of those have a seal ring, do they not? Resilience is your friend in this case - think of the plastic insert nuts that are used in a lot of applications in lieu of a lockwasher.

I might skip on the rest of it. Maybe some permatex on the GAV bushing. I think that's a taper thread though.

Joe K

[Gary WA]

I use nothing-built many carbs, still do, Roads aren't as rough as they were in the 30's.

[SeaSlugs]

yea just assemble it with the proper gaskets

[johnbuckley]

I use loctite on the butterfly and choke plate

[Tom Wesenberg]

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I've never used Loctite on the choke and throttle plate screws, and have never had them come loose, but it would be good for peace of mind.

[George Miller]

If the jets are put in tight like they should be, they will never come out. Throttle plate screws should be staked on the back side of the shaft where the threads come through. Lock tight has no place in the carb. Carb throttle plate screws were staked on all carbs from the factory that I ever worked. Lock tight is over used.

[oj]

I have a tub of petroleum jelly on my carb bench and use it on most all body screws - I'm no scientist but I think it helps.
Like others I use the blue loctite paste on throttle blade screws - if those screws get loose and one falls out the throttle blade will rotate down into the bore and wedge the throttle 'open' and you'll be in for the ride of your life. Don't worry about the missing screw, it won't raise any havoc.
The only other lubricant I use is 'molybdenum' for the throttle shaft (& accelerator pump arm on a modern holley).

[160B]

I have never used Loctite or any thread lock of any type in carburetor rebuilding and have never had one come loose. Use gaskets not the plastic but the paper and you should be fine!!

[johnbuckley]

Originally Posted by George Miller

... Throttle plate screws should be staked on the back side of the shaft where the threads come through....

Sorry friends,- have you a translation for "staked" into British English?

[Purdy Swoft]

I don't put anything on the threads, I don't stake them either. I figure that I may need to remove them later. Have you ever tried drilling out a butterfly screw. I don't think that there is a lot of risk of loseing a butterfly screw on a model A with an updraft carburetor.

[Glenn Thoreson]

Originally Posted by johnbuckley

Sorry friends,- have you a translation for "staked" into British English?

It means to mash the screw a bit on the end opposite the head. You don't need to beat it to death, just deform it a bit. Properly done it won't come out on it's own but you should be able to unscrew it with a little effort without ruining the threads in the shaft. On another note, nothing is required on the threads of carburetor parts except some anti-sieze on the threads of the center bolt that holds a Model A carb together. Any kind of "goo" inside a carburetor is a really bad idea.

[George Miller]

Originally Posted by johnbuckley

Sorry friends,- have you a translation for "staked" into British English?

What it amounts to is driving a center punch into the last thread on the bottom side of the shaft. It rolls some metal from the male thread into the female thread. That is not how they did it but it works. They most likely used a special punch in a press. If you do this it would be good to support the shaft so you do not bend it.

[George Miller]

Originally Posted by Purdy Swoft

I don't put anything on the threads, I don't stake them either. I figure that I may need to remove them later. Have you ever tried drilling out a butterfly screw. I don't think that there is a lot of risk of loseing a butterfly screw on a model A with an updraft carburetor.

If you do not over do it they will come out when you need to take them out. But I agree if they are in there good and tight they will not come out.

[johnbuckley]

Strake...Hmm, if I tried that I'm sure I'd bend the shaft, or over do it and thus damage the shaft thread when it was time to undo them! Think I'll stick to blue loctite