Rebuilding Zeniths - found a broken bit - anyone got a spare?

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MajorBenz
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Model you own: w108
Region: Victoria
Location: Melbourne

Rebuilding Zeniths - found a broken bit - anyone got a spare?

Post by MajorBenz » Wed 23 May, 2018 8:50 pm

Hello fellow benzers,
I have been getting very aquainted with my Zenith 35/40's lately. Photographing, and then dissasembling each section slowly and methodically. Reading various literature to try and understand how these complicated buggers work.

Upon removing the cover off the "Automatic starting device" I found that a tiny part seems to have snapped off and fled the vehicle. The broken part is refered to as a "stop lever" in the Merc Workshop manual.

Here is a pic in the exploded diagram:

Image

Here it is mounted in the device:

Image

Here is MINE mounted in device - note the lack of spring and "adjusting screw"...

Image

Here is MINE after being removed - the little arm that stuck out at 90 degrees has broken off. Taking the spring and screw with it I guess...

Image

I gather this mechansim is for adjusting the choke via a hole in side of housing, as seen here:

Image
("3'" points to the adjusting screw poking throught the hole)

Perhaps the previous owner was a bit too enthusiastic with his "adjustment" and busted the thing off. :Doh:

SO.... I need to replace the Stop lever(42), Compression spring (43) and Stop Screw (44) as pictured in first diagram.
If any ozbenz members have these bits lying around unused, I would be eternally grateful to have them. Would rather not have to buy a whole carb just for these tiny bits, as the rest of it is in good shape.

Give, so that another precious W108 can live. :pray:
(Am happy to throw a few bucks your way too if need be)
Cheers,
Dan
Melbourne
Silver 1969 280S - "Grace"

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John Green
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Re: Rebuilding Zeniths - found a broken bit - anyone got a spare?

Post by John Green » Fri 25 May, 2018 8:08 pm

That is the adjustment for the fast idle speed when cold. So I guess it is the choke, but in reality it is only controlling the additional air, not the additional fuel. Still a very important part.
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http://mbspares.com.au - Supporting Australia's Mercedes-Benz Enthusiasts.

Henry Schuman
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Re: Rebuilding Zeniths - found a broken bit - anyone got a spare?

Post by Henry Schuman » Sun 27 May, 2018 12:21 am

There is only 1 fast idle screw needed since both carburetors are linked together .

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MajorBenz
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Model you own: w108
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Location: Melbourne

Re: Rebuilding Zeniths - found a broken bit - anyone got a spare?

Post by MajorBenz » Sun 27 May, 2018 12:43 am

Henry Schuman wrote:
Sun 27 May, 2018 12:21 am
There is only 1 fast idle screw needed since both carburetors are linked together .
Well well, the plot thickens....
Thanks for your reply Henry, I had wondered this. When I first got the car it seemed to drive ok. (Before I left it sitting neglected for a year). I didn't find any missing bits inside the cover. Perhaps they never were missing?

The carb closest to the firewall does have it's fast idle screw. So your saying: when this screw is properly adjusted it will keep the other carb at the same fast idle setting via the linkages? It makes sense! Maybe they break the other screw off if in the Benz Factory?

I think you just made my night dude! :notworthy:
Silver 1969 280S - "Grace"

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John Green
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Re: Rebuilding Zeniths - found a broken bit - anyone got a spare?

Post by John Green » Sun 27 May, 2018 9:31 am

MajorBenz wrote:
Sun 27 May, 2018 12:43 am
Henry Schuman wrote:
Sun 27 May, 2018 12:21 am
There is only 1 fast idle screw needed since both carburetors are linked together .
Well well, the plot thickens....
Maybe not... Yes the two are linked, but the fast idle and choke settings override the base settings that are linked together. Have a good look at how it works. Once the choke has gone though the warm up cycle and the bimetalic spring has tightened up the idle setting is backed off until it hits the stop that is then linked to the other carb.
M.B Spares & Service 14-16 Lyell St, Fyshwick ACT. Ph 02 6239 1099

http://mbspares.com.au - Supporting Australia's Mercedes-Benz Enthusiasts.

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