Where to start? - 1971 250 w114 m130 zenith carbs - Page 9 - Mercedes-Benz Forum

Reply
 
LinkBack Thread Tools Display Modes
post #81 of 138 (permalink) Old 02-18-2015, 05:36 PM Thread Starter
w108,107 Parts Hoarder
 
Fonzi's Avatar
 
Date registered: Jun 2010
Vehicle: 4Keep:450slc5.0cab 280sl5sp 280se4.5 500seAMG 2sell:500sl92 380se83 300se86 350sl4sp 75slc MorInSig
Location: Philadelphia Area
Posts: 18,795
Mentioned: 27 Post(s)
Quoted: 1626 Post(s)
Lifetime Premium Member
Garage
(Thread Starter)
Where to start? - 1971 250 w114 m130 zenith carbs

I stole a few more minutes to mess with the car. Knowing the last time I was at the car I couldn't even get it to start when I first tried, my expectations are low. I did have it to the point where I was able to drive it around the block, but I screwed it all up since then, and will need to start over. I didn't have too much time, so just cranked it up:
- linkage between carbs disconnected so they can be tuned independently for idle.
- squirt each of the accelerator pumps 1-2 times
- press remote starter button. Run. Stall.
- I could see that the front choke was too far open so I rotated the housing and started the car. It was running. Choke wires were disconnected. Hmm...
- while running, I connect choke wires with the aftermarket setup of both chokes together (not the maybe original rear choke wire I think I found).

http://youtu.be/_PgNa6ewBVo

- Within less than a minute the chokes were too wide open and it was starting to stall. Hmm... Must be too lean. (Don't bother to think much about that vacuum leak. Right? Nope.).
- disconnect choke wires and have to adjust housing to keep it from stalling. (Oh... Now I know why I was running too rich later... Keep reading if you care.)
- so I start messing with all the million adjustments: idle mixture screw, small throttle linkage, stop screw, and even the choke housings (which I didn't think too much about the gradual cooling due to lack of electric).
- the idle was really sensitive to the choke position, and I could have stalled it easily by tilting either of them by hand. Hmm... Why so sensitive? Maybe bad idle mixture screw setting?
- the exhaust started getting really smokey. Too rich obviously. But when I opened either choke plate manually, idle would slow. Hmm...
- finally it stalled and I called it quits.

I took this picture of the temp after it stalled. I am pretty sure oil pressure was always good.
Where to start? - 1971 250 w114 m130 zenith carbs-imageuploadedbyautoguide1424306075.641622.jpg

I know it's not much, but in trying to tune these, I think it is good to record everything as best as possible.

.

My signature:
Click for list of my 32 MB since 2010. If, you want 70's-80's Mercedes tuner wheels, let me know.

Last edited by Fonzi; 02-18-2015 at 05:43 PM.
Fonzi is offline  
Sponsored Links
Advertisement
 
post #82 of 138 (permalink) Old 02-18-2015, 07:13 PM
BenzWorld Elite
 
rumb's Avatar
 
Date registered: Oct 2012
Vehicle: 1968 250S, 1991 300se, 1998 SL500, 1977 450SEL 6.9. Past MB's; 300SD, 300E, 300TE, 190E, ML420
Location: Colorado
Posts: 2,363
Mentioned: 6 Post(s)
Quoted: 427 Post(s)
Garage
Correct way to start car is depress pedal slightly to set chokes/fast idle.

then turn key until starts. no pumping of pedal.

Hot starts hold pedal to floor, do not pump at all and crank till starts.

is your idle adjust screws set to 2.5 turns initially? when cold are both choke plates closed or mostly closed? did you see the test on cold engine just turn key on and in 2 minutes the chokes should open up.

I know you are just trying to get it to run. can you get it to a point where it will warm up and idle?

adjust choke just enough so you can get engine running and idling.

Then do you balancing and idle speed settings with the little turnbuckles.
rumb is online now  
post #83 of 138 (permalink) Old 02-18-2015, 07:26 PM Thread Starter
w108,107 Parts Hoarder
 
Fonzi's Avatar
 
Date registered: Jun 2010
Vehicle: 4Keep:450slc5.0cab 280sl5sp 280se4.5 500seAMG 2sell:500sl92 380se83 300se86 350sl4sp 75slc MorInSig
Location: Philadelphia Area
Posts: 18,795
Mentioned: 27 Post(s)
Quoted: 1626 Post(s)
Lifetime Premium Member
Garage
(Thread Starter)
For simplicity, I will respond in all caps. It's not yelling.

[QUOTE=rumb;11389962]Correct way to start car is depress pedal slightly to set chokes/fast idle.

I AM STILL STARTING WITH REMOTE STARTER. NEVER QUITE FIGURES THAT HALF PEDAL THING OUT YET.

then turn key until starts. no pumping of pedal.

IT SEEMS THAT THE CAR STARTS MUCH EASIER WITH A SQUIRT.

Hot starts hold pedal to floor, do not pump at all and crank till starts.

MY SEDAN SEEMED TO START WITH A TWIST OF THE KEY ONCE WARM. IM CLUELESS

is your idle adjust screws set to 2.5 turns initially?
I AM ASSUMING YOU MEAN THE IDLE MIXTURE NEEDLE SCREW IN BASEPLATE. RIGHT? THATS ABOUT WHERE IVE HAD IT BUT I MESSED WITH THEM LIKE NUTS TOO,

when cold are both choke plates closed or mostly closed?
YES

did you see the test on cold engine just turn key on and in 2 minutes the chokes should open up.
I DID SEE THAT. I DIDNT DO THAT SPECIFIC TEST, BUT THEY OPEN, TOO FAST FOR MY CAR'S CURRENT STAKE IT SEEMS.

I know you are just trying to get it to run. can you get it to a point where it will warm up and idle?
I THOUGHT I HAD IT THERE, BUT MESSED WITH IT AGAIN WHEN I COULDNT DRIVE IT BACK INTO THE DRIVEWAY. SCREWED IT ALL UP.

adjust choke just enough so you can get engine running and idling.
NEXT TIME ITS WARM I THINK I NEED TO LOOK FOR OBVIOUS VACUUM LEAKS AND SET EVERYTHING I CAN TO SPEC.

Then do you balancing and idle speed settings with the little turnbuckles.

ON THE TURNBUCKLES, THE FRONT ISNT TWISTING AS EASILY AS THE BACK. I WIDH I KNEW HOW TO SET A FACTORY SPEC ON THAT.

.

My signature:
Click for list of my 32 MB since 2010. If, you want 70's-80's Mercedes tuner wheels, let me know.
Fonzi is offline  
post #84 of 138 (permalink) Old 02-18-2015, 10:34 PM
BenzWorld Extremist
 
Date registered: Sep 2012
Vehicle: 300sel W109, 280S 70 , 220s 62. 230 66. Lancia Flavia 63.Pininfarina
Location: Totteridge London.
Posts: 807
Mentioned: 0 Post(s)
Quoted: 59 Post(s)
Indeed, concise and simpler!
adler is offline  
post #85 of 138 (permalink) Old 02-20-2015, 05:40 PM
BenzWorld Elite
 
dgosh28's Avatar
 
Date registered: Oct 2011
Vehicle: '71 250, '78 450SLC 5.0, '78 450SL, '81 380SLC 5.6, '89 260E, '15 Kia Sorento
Location: Houston, TX
Posts: 5,169
Mentioned: 24 Post(s)
Quoted: 103 Post(s)
Fonzi, I am counting on you to figure these carbs out so you can walk my through tuning mine.
audley115 likes this.
dgosh28 is offline  
post #86 of 138 (permalink) Old 02-20-2015, 05:47 PM
BenzWorld Elite
 
dgosh28's Avatar
 
Date registered: Oct 2011
Vehicle: '71 250, '78 450SLC 5.0, '78 450SL, '81 380SLC 5.6, '89 260E, '15 Kia Sorento
Location: Houston, TX
Posts: 5,169
Mentioned: 24 Post(s)
Quoted: 103 Post(s)
How important is it to have the electrical choke wires hooked up that plug into the front of the carbs? The carbs I bought for my car had the wires cut and I didn't know to install them, I realized it months later. I have a set I can install if it will make a big difference. The car starts, idles, and drives fine without them as far as I can tell.
dgosh28 is offline  
post #87 of 138 (permalink) Old 02-20-2015, 06:52 PM
BenzWorld Elite
 
rumb's Avatar
 
Date registered: Oct 2012
Vehicle: 1968 250S, 1991 300se, 1998 SL500, 1977 450SEL 6.9. Past MB's; 300SD, 300E, 300TE, 190E, ML420
Location: Colorado
Posts: 2,363
Mentioned: 6 Post(s)
Quoted: 427 Post(s)
Garage
? front of carb? picture maybe?

there is a switch on the front of the front carb that controls the tranny kickdown when you come to a stop.

the chokes just have one wire.
rumb is online now  
post #88 of 138 (permalink) Old 02-20-2015, 09:07 PM Thread Starter
w108,107 Parts Hoarder
 
Fonzi's Avatar
 
Date registered: Jun 2010
Vehicle: 4Keep:450slc5.0cab 280sl5sp 280se4.5 500seAMG 2sell:500sl92 380se83 300se86 350sl4sp 75slc MorInSig
Location: Philadelphia Area
Posts: 18,795
Mentioned: 27 Post(s)
Quoted: 1626 Post(s)
Lifetime Premium Member
Garage
(Thread Starter)
Yeah. Chokes are in the rear of the carbs with wire connections on domed shaped things that you can twist if they are cleaned and bolts are loosened.

I think I recall you mentioning another wire that was related to something that stops dieseling when the car is shut off.

.

My signature:
Click for list of my 32 MB since 2010. If, you want 70's-80's Mercedes tuner wheels, let me know.
Fonzi is offline  
post #89 of 138 (permalink) Old 02-21-2015, 05:50 AM
BenzWorld Elite
 
rumb's Avatar
 
Date registered: Oct 2012
Vehicle: 1968 250S, 1991 300se, 1998 SL500, 1977 450SEL 6.9. Past MB's; 300SD, 300E, 300TE, 190E, ML420
Location: Colorado
Posts: 2,363
Mentioned: 6 Post(s)
Quoted: 427 Post(s)
Garage
the fuel return valve on the front carb - brass - is what prevents dieseling and vapor lock.

Last edited by rumb; 02-21-2015 at 05:56 AM.
rumb is online now  
post #90 of 138 (permalink) Old 02-21-2015, 05:56 AM
BenzWorld Elite
 
rumb's Avatar
 
Date registered: Oct 2012
Vehicle: 1968 250S, 1991 300se, 1998 SL500, 1977 450SEL 6.9. Past MB's; 300SD, 300E, 300TE, 190E, ML420
Location: Colorado
Posts: 2,363
Mentioned: 6 Post(s)
Quoted: 427 Post(s)
Garage
Here are some diagrams from BMW - they use the same Zenith with a few differences. Help you visualize a few things.
Attached Thumbnails
Click image for larger version

Name:	fig01-02s.gif
Views:	102
Size:	71.4 KB
ID:	1334257   Click image for larger version

Name:	fig03s.gif
Views:	73
Size:	27.6 KB
ID:	1334265   Click image for larger version

Name:	fig11s.gif
Views:	110
Size:	72.4 KB
ID:	1334273  
rumb is online now  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > General Mercedes-Benz Forums > Vintage Mercedes-Benz

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











  • Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
     
    Thread Tools
    Show Printable Version Show Printable Version
    Email this Page Email this Page
    Display Modes
    Linear Mode Linear Mode



    Posting Rules  
    You may post new threads
    You may post replies
    You may not post attachments
    You may not edit your posts

    BB code is On
    Smilies are On
    [IMG] code is On
    HTML code is Off
    Trackbacks are On
    Pingbacks are On
    Refbacks are On

     

    Title goes here

    close
    video goes here
    description goes here. Read Full Story
    For the best viewing experience please update your browser to Google Chrome