Carb Disassembly Tips

[ursus]

I'm about to clean and rebuild several Zenith Model A and B carbs and looking for a better approach to removing the choke and throttle plate screws. This has been previously problematic because repeated efforts to turn out the screws ends in buggered up screw heads and zero movement of the screws.

I have used releasing agents like Kroil and Free-All, mild application of heat, turning the screws in slightly before backing out, as well as increasing levels of profanity, all too often without success.

What tips or tricks have worked for you folks? Thanks!

[nkaminar]

I am not sure if this would not damage the shafts, but I have used an impact screw driver for stubborn screws. Maybe back up the shaft with a heavy weight.

another option is to drill out the screws, clean up the threads in the shafts, and then buy new screws.

https://www.amazon.com/CRAFTSMAN-Imp...s%2C353&sr=8-5

[Jim/GA]

Use hollow ground screwdrivers that exactly fit the screw slot width and length. They apply a lot of torque without “camming out” of the slot.

[700rpm]

"Use hollow ground screwdrivers that exactly fit the screw slot width and length".
That’s the ticket.

[CA Victoria]

Took a few apart today……
Heat the screws first, i have used a handheld solder torch or carefully w/a very small tip with my victor torch set.
Use a good screwdriver using as much down pressure as you can muster. If the screw begins to strip -stop & use a thin Dremel cutoff wheel to re establish the slot.
Have not had to drill or dissect one since using heat…

[Brentwood Bob]

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Hit with pb blaster and then press hard as you turn it out.

[Tom Endy]

Be very careful with the disassembly. A lot of good Zeniths have been destroyed during disassembly. The attached document should guide you through it.

http://www.santaanitaas.org/wp-conte...etor-11-07.pdf

Tom Endy

[Gary WA]

Originally Posted by ursus

I'm about to clean and rebuild several Zenith Model A and B carbs and looking for a better approach to removing the choke and throttle plate screws. This has been previously problematic because repeated efforts to turn out the screws ends in buggered up screw heads and zero movement of the screws.

I have used releasing agents like Kroil and Free-All, mild application of heat, turning the screws in slightly before backing out, as well as increasing levels of profanity, all too often without success.

What tips or tricks have worked for you folks? Thanks!

Heat Heat then hit with cold water. should be able to turn out by hand.!!!

[jeepguy1948]

Hollow Ground screw drivers are also known as gunsmith’s screwdrivers

[MrBruce]

Urus
I've taken about 25 - 30 carbs apart in the past month and came up with a unique (I think) way to get the jets and screws out. The cap jet's are broken off and are 5m.75 pitch which is small and I heated them in the throat and then took a long piece of wax and melted it around the jet and took a really small easy out 1/8 and gently tapped it in and they screwed right out. I did it on the early GAV's that have the jet at the bottom, now that was a trick because someone had already mess up the screw driver slot, but after a little heat and wax they screwed right out. I put a little heat on the throttle plate and then touched the screws with wax and a screw driver that was a little bigger than the screw and so far everyone has come out. I was shocked and don't know what possessed me to think of it but 85% of the time the part comes loose. Hope this helps

[Brentwood Bob]

Bruce, will have to give that a try.