Marvel-Schebler TSX-458 carburetor choke shaft seal

dbotos · Jun 26, 2013

Anyone know where I can get just this seal? I got the basic carb kit and it comes with the one for the throttle shaft, but I need the one for the choke shaft too. Either that, or I need to find a place that sells tiny little lip seals. The one for the choke shaft looks like it would be 3/16" ID, 5/16" OD, and about 1/8" thick...

dbotos · Jul 2, 2013

Still looking for this part. In my googling, I noticed that carb shaft seals are sometimes referred to as "packing". When I searched using that term, one of the hits was for the choke shaft packing for a Ford 8N that basically looks like a thick felt washer (see examples of rubber and felt seals below). Any thoughts/comments/expletives on the felt ones? Seems like that might be easier to find generically or just to make. Would it help to grease the felt? Also found this post where some guy used faucet packing:

'25 Dodge carburetor air leak cure

davkir · Jul 2, 2013

McMaster-Carr is always a good place to look for items like this.

dbotos · Jul 2, 2013

Thanks. I checked McMaster when I first started looking for generic ones. All the standard ones they had were 1/4" ID or larger. They did have some 3/16 ID x 5/16 OD in PTFE, but they are about $20.

ThomasH · Jul 2, 2013

The older auto carbs that I have worked on used O-rings with some silicone grease. Does the packing fit into a recessed spot? If not, I would think that an O-ring slightly stretched over the shaft with a very small amount of grease would be something to try.

dbotos · Jul 2, 2013

Yup, the seal fits in a counterbore where the shaft goes into the casting. An AS568A-008 o-ring looks like it would work (0.176 ID, 0.070 thick, 0.316 OD). Home Depot has a 10-pack for ~$2 - I'll have to pick some up and try one...

DANCO #36 O-Rings (10-Pack)-96750 at The Home Depot

Thanks!

dbotos · Jul 7, 2013

Looks like it'll work. There's one of those little stamped brass seal retainers that goes in there too, but for the sake of clarity, I left that out of the picture and positioned the o-ring at the top of the counterbore. Thanks again for the tip!

ThomasH · Jul 7, 2013

Good deal! It looks like it was made for such a seal. I would get some silicone grease (same as they use on o-rings for plumbing) and put a small amount on the shaft to allow it to rotate without wearing on the o-ring.

dbotos · Jul 9, 2013

I've got a little blob of Dow Corning silicone vacuum grease in a baggie at home that I've had for years. Time to put some of it to use.

rsallen · Jul 9, 2013

Heres what I don't understand,
Why does the choke shaft even need a seal?
I understand a throttle shaft needing a reasonable seal, but a choke shaft? As long as the choke is free to do it's thing and isn't falling apart what is the big deal?
If it's too sloppy, sleeve it, put a little grease on it, keep it lubed now and then. It's not like it has to seal against a great vacumn pull. And in fact it designed to open a bit with some vacumn.

What am I missing?