Zenith 35/40 INAT Carburettors - PeachParts Mercedes-Benz Forum

aluminum · #1 12-10-2019, 06:01 PM

Hello

Disassembly Help Request

I want to clean out a set of 1968 35/40 Zenith Carbs I got that look great however I can't seem to remove the Top Cover ? is some hidden screw perhaps ?
(1) Removed the Choke Rod (2) the 8 top cover Screws but the cover does not come up ? is a small slot in the Top Cover Gasket ( looking from the side )
you can see on both Carbs that looks like a place to insert a screw driver perhaps to pry up .

I tried this and indeed the Cover pry's up a Small amount however it feels like if I continue it well Brake something ?

Removed this set from a 1968 sedan 250S with auto transmission

this type / Year - " Carb set does not have a Center screw rod going up to hold the Air Cleaner coming right from the center of the carb unlike my 1967 250 S
it has a hole / place for such a threaded rod but nothing in it ( and no screw at the bottom of the hole )

Is their a hidden screw somewhere ? I DO NOT Want to ruin this set of Carbs and force the cove off . Just to hard to find them these days .
Checked my Manuals and they both say just remove the 8 Cover bolts / choke rod and lift off hummm It feels like it has a screw in the center ?

Thanks for any advice

rumb · #2 12-11-2019, 10:22 AM

Screw in center of carb where air cleaner bolt goes.

All you need to know aboutZenith :http://www.jaimekop.com/mb-zenith-carb-manual/

aluminum · #3 12-11-2019, 02:41 PM

Quote:

Originally Posted by rumb

Screw in center of carb where air cleaner bolt goes.

All you need to know aboutZenith :Mercedes Benz Zenith Carb Manual – JaimeKop.com

Thant's what I thought and the first place I looked ? When I looked at that the bottom of the Hole is SOLID with what looks like pot metal. The side walls of the Hole are threaded to hold a threaded rod most likley for the type of Air Cleaner like on my 1967 250 S

This set I am working with is from a 1968 250 S that has a different Type Air cleaner that does not attach to the carbs from the center of the Dual Carbs .

Perhaps someone Put some Epoxy in the Bottom of the hole covering the Hole /Screw from air leaks ?

I did read that Those Carbs sometimes have problems caused by people over tightening The 67 type Air Cleaner's down on the Carbs to tight and Create a Bow in the center of the Carbs . This causes a Air Space under that and the Car does not run right .

Humm First I well try to dig out the center with a sharp Pick . Now that you mention the Center Screw I remember it from my 67 Carbs but those I could see the screw and once removed up comes the cover .
So Manual is wrong is 9 Screws not 8 Screws holding the top cover down

Thanks for reply

Thanks for the Help . I hate to just try and force something then brake it Happy Holiday Season
Note : I don't think I can put links here but the Car is here listed as a 69 but is a 68
Pick-n-Pull 1969 Mercedes-Benz 250 Stockton ca 95215 added Dec 3rd Motor looks good steering is broken

rumb · #4 12-11-2019, 05:12 PM

It should use a smaller regular screwdriver.

aluminum · #5 12-12-2019, 01:32 PM

Yup Dug it out and the Screw was indeed under what looked like J B Weld

that Gray color . First one ( Screw ) came right out . is the same size Thread but the Diameter head of the screw is smaller.
Second Screw would not budge so I had to drill out the Head off then lift off the Top Cover of the carb then removed the screw vice grips .

I bit of damage from the Drilling but I think the Carb well work if I reseal after reassembly.

Any Place you can just buy the Mounting Gaskets Carb to manifold and replacement " Secondary Vacuum Diaphrams " .
I Soak the Carb Body's in Gasoline before disassembly overnight and it seems to keep the Gaskets from tearing upon Tear Down a experiment

As all the rebuild kits I see online don't have any Accelerator Pumps in the kits ? well then hummm .

Thanks for the reminder , Knowledge , of those screws

rumb · #6 12-12-2019, 07:51 PM

For the manifold gaskets just go buy some gasket paper, trace and cut them out. Save your old accel pumps the new blue rubber replacement rings fall off and no way to make them work.

just buy a gasket kit that includes the sec diagphram

you might try buying some of these leather cups, hopefully they will work.

https://www.ebay.com/itm/PORSCHE-356-ABC-Zenith-32NDIX-Carburetor-Accelerator-Pump-Diaphragm-Leather-Cup/163188490262?hash=item25fecac016:g:aoEAAOSwiIRbkXRi

aluminum · #7 12-25-2019, 05:08 PM

Quote:

Originally Posted by rumb

For the manifold gaskets just go buy some gasket paper, trace and cut them out. Save your old accel pumps the new blue rubber replacement rings fall off and no way to make them work.

just buy a gasket kit that includes the sec diagphram

you might try buying some of these leather cups, hopefully they will work.

https://www.ebay.com/itm/PORSCHE-356-ABC-Zenith-32NDIX-Carburetor-Accelerator-Pump-Diaphragm-Leather-Cup/163188490262?hash=item25fecac016:g:aoEAAOSwiIRbkXRi

Hello Rumb

Merry Xmas > heck I forgot how do you remove the Accelerator Pump zenith 35/40 inal Humm I did this before but can't seem to remember just how you Get them out ? I removed the jet at the Bottom and can push the Pump Upward but not all the way Out ? the Pump works But I would like to clean it all out and I forget how to remove it ?

Or anyone that Knows how . I think this set is from a 1968 250S Dual carbs

rumb · #8 12-25-2019, 08:23 PM

confused: the pump just pulls up out of the body, how do you push it?
Picture of what you are doing would be helpful. We may be talking about different things.

aluminum · #9 12-26-2019, 01:10 PM

Quote:

Originally Posted by rumb

confused: the pump just pulls up out of the body, how do you push it?
Picture of what you are doing would be helpful. We may be talking about different things.

I see a Photo ( top of Photo you can see Lever and top of Pump ) from the Top of the Accelerator Pump I can add here but it does not come out only lifts up a bit then stops , don't want to brake it . Pump Lever swings out of the way .

The Accelerator Pump you can view from the Top and comes out from the top . it pumps from downward movement .
However for removal it does not come out all the way only comes up some. with that part of the Carb Body turned upside down you can see a Jet directly under the Accelerator Pump but smaller in diameter . I removed this jet and you can see the Bottom of the Accelerator Pump and push it upward but only a small amount
and it does not come out as if something is locking it in ?

I assume Fuel go's in the jet at the bottom and the pump when depressed pumps Fuel out the Tube in the venturi

How did I push it ? well Since it did not pull out of the top only comes up some then stops I removed the jet at the bottom and pushed the bottom of the pump upward but with the same result , only moves a bit then stops as if locked in somehow ?
Perhaps I should push or pull it harder ? humm I was pulling quite hard already but it seems locked in ? ( it pumps fine perhaps i well just put it together as New Pumps don't come with the Very costly kit anyway ? )

Just found this Video on You tube . you can see the Pump in video # 5 https://www.youtube.com/playlist?list=PLKDwdyP9Nwd2PeOlU_L7r6L_jWl2OXG-
7&app=desktop
After viewing the video it looks like if I force it the pump well be ruined humm

dobrodan · #10 12-27-2019, 11:34 AM

You have to remove the lever assembly first. The pump should come out with maybe a little resistance from the diaphragm at the top. Pull harder.

aluminum · #11 12-27-2019, 02:23 PM

Got it out thanks all : was just stuck from Gunk and the like , No Lever removal needed
just push from below and a little Lube up top and she came out still in good shape .
good thing as you can't buy them anywhere I can find . Carb Kits come without them

glmoore0001 · #12 11-04-2022, 11:05 AM

I know this is an old post, but I found a guy on ebay that had a large batch of leather cups for the Zenith. I bought 4 pcs in May of 22. He may or may not still have them.