Hi guys - hope everyone’s had a good weekend so far.

I am about to rebuilt a set of Weber’s which will be a first for me. I’ve rebuild quite a few carb on the British cars I cut my teeth on, so am at least familiar with carbs in general.

With the British cars all you need to do is see if can wiggle the throttle shaft to see if you have any play, if you do they need to be addressed.

Is there a similar test on the Weber’s I should be checking - I assume so.

False air is no fun.

Thanks!

I don't know how to bench test, but on a running car you can spray carb cleaner and if it runs worse you've got leakage. You can also glob bearing grease on the suspect leak, and if it runs richer, you also have leakage.

Hi Perry! Thanks for the response.

Pulling then back off wouldn’t be the end of the world, and will keep those tests in mind, but was hoping to find a way to check beforehand. I have two spare sets so can pick the better of the two if there is a difference.

Hey guys...

Great question and answer.

One to remember.

In my case I could “jiggle” the shafts up and down on my triple throat Weber 40’s - was obvious the shafts were leaking air. Having them repaired made a huge difference to the engine performance both in smoothness at all rpm’s and power.

Cost out getting the throttle shaft bushes redone,its a specialist job and is normally expensive...not DIY by any means,it's an involved process requiring special jigs and reamers.
The repair work is the big cost ,just don't get the cheapest price because you won't get what you really need.
Folks doing this are thinning out I understand legend Paul Abbot is scaling back on new work these days I guess he may be retiring ?
Parts Klassic (?) do them from memory and think there are a few others,good luck.

Inquire at Blackline Racing. Murray Utah. Ustah be Air Cooled Engineering, A.C.E.

If they're off you can look for carbon trails on the butterfly's

Wiggle the throttle shafts. Also while the carbs are out, shine a light on the throttle shafts to check for a bent shafts or butterflies. Other than that, just clean them and run them. Or you can upgrade to dells. They don't wear like the Webers do....and run much better.

You can find the Weber manuals here:

http://p914-6info.net/Manuals.htm

Scroll down a bit.

Good info, thanks gentlemen.

And this is why - as you all recommended - you clean carbs before using them.

Click to view attachment

(Dupe - sorry)

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While you have these accelerator pump covers off, use a medium course sandpaper on a flat surface (eg granite cabinet top) to sand the the covers flat. Tightening the four bolts over the many years can bend the bolt hole "ears".

Good tip, thanks Keith.