TN-28 carb overhaul

[shoestringmariner]

quote Jim Moffatt:

To save a lot of effort you can install a #109 o-ring under the primer spring. It forms a perfect seal between the plunger and the plunger tube.
Leave the old parts in the carb simply add the o-ring. I have done this to several motors and it works excellent.

Great tip. If we could create a TN info thread or sticky…this should be in it

[obnut]

Well I put the carb in the freezer for about 5 hrs. Using the tools that David Poche discussed in his articles, I was able to pluck those blasted stubborn washers and leather seals right out of there. The brass washers must contract with the cold faster than the aluminium carb housing. Anyway it worked. I do need new leather seals as they are not in very good shape.

[aquasonic]

Congratulations on the successful extraction of those ornery washers. They do seem to succumb just about the time you are ready to give up. I always replace the old washers with new, and then comes the easy part…putting it back together.

Please take care on the reassembly of the primer washers so that everything goes back in the proper sequence and orientation. I have rebuilt eight of these carburetors now and most of them had brass primer washers or brass cup that were upside down or reversed.

The brass cup goes open end up. The top brass washer goes concave side down. The bottom brass washer goes convex side up. The leather seals go smooth side down, unless you get NOS leather seals, in which case they go cupped side down.

If the cork float is not decayed, it can be sanded and recoated, and it will work just fine.

[legendre]

quote ShoestringMariner:

quote itchy:

gas was running from everywhere on the carburetor. But, believe I have
a float problem and will coat the float cork with something different than I have been using.

I’ve read that gas coming out from the top is a float issue and only out of the plunger bore when depressed is a leather seal issue.

Correct on both counts – but as ever, I’m sure exceptions can be found.

[Author]

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