1970 250c zenith carbs - So HERE is where the w114 folks are!!! - PeachParts Mercedes-Benz Forum

fonzi · #1 03-22-2015, 11:07 PM

Holy cow. THIS looks like the real w114 forum, not that benzworld stuff. Too bad I started all my carb work over there. I've had fun, but would like more input than I've gotten from the BW crowd.

Can you guys take a look at these videos and tell me where you think I should go from here if the car is stalling when I put it in gear?

Mercedes-Benz Forum - View Single Post - Where to start? - 1971 250 w114 m130 zenith carbs

http://youtu.be/ClIhjQr50ec

http://youtu.be/n7ERs2bZuew

Two more vids to come

http://youtu.be/mT50BN96VmY

One more short one on way.

Last vid from the day:

http://youtu.be/d-mP5zKBaiQ

So... Vacuum leaks you think?

Before, when I pushed on the brake pedal in park, the rpms would increase (signifying a vacuum leak, right?).

I did start it up one more time tonight at 38 Degrees F and then decide to turn the idle mixture screws 1/2 turn counterclockwise each to lean out the mixture a tiny bit. This was all with the air filter on. The car actually ran with my foot on the brake in park for about 5 seconds which was a big improvement.

I wonder. Does the torque converter or other transmission components lose fluid from sitting, and maybe get better and stall less with the foot on the brake while in gear?

I've only driven this car half way around the block once before and was not able to get it running to get it back into my driveway. So I pushed it home. That sucked. I want to make sure this car is able to make it back if I pull it out of the driveway this time.

Any suggestions?

Thank you!

dobrodan · #2 03-23-2015, 08:45 AM

You can't even think about the carbs until you've adjusted the valves, done a compression check, fixed all vacuum leaks, and set the points and timing. You'll never get the carbs right if the other things are wrong. And you should only use one UniSyn, alternating between carbs, otherwise how do you know they are the same? Start with finding your timing mark after the points are set. When you set the fast idle only the front carb should be adjusted. The screw for the fast idle on the rear carb should be removed. Make sure the tops of the carbs are tight, especially the middle screw. They often get out of shape by overtightening the cover screws.
I just looked at your 3rd and 4th vids. You've got major blow by. And very low oil pressure. You have bigger problems than a carb adjustment.

todds · #3 04-10-2015, 04:46 PM

If the carbs are way the heck out of balance it will cause fuel to dribble out into one of the main venturis. Also the car will run like crap. I'd guess that your front to rear balance is way off, you need a uni-syn carb balancing tool and the little plastic carb hood adapter to attach it to your carbs. Then you can see how much air each one is drawing. I'd basically start by disconnecting ALL the linkages and undoing the little return springs on the zeniths so you can make sure your throttles are totally closed. Then connect the linkages back up such that they don't influence the position whatsoever, so that the ball and sockets just plug into each other without moving anything. At that point your car probably won't start because the throttles will be too far closed to run. If it does run and still races like that then you definitely have vacuum leaks! If it won't run then you can start cracking open the throttles tiny bits at a time until you get it to idle and then decide how fast you want it. It's supposed to be around 750-800 in gear. Oh, you should also get a tach, they're not that expensive and really easy to hook up under the hood while you're working...

It's a long process but you ought to at least be able to get it to stop racing like that and go into gear well enough!