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Hello, new to having mercedes. I picked up a 72 250 with the twin zenith carbs . Still has original owners documents that came with it. Only issue is it sat for a couple years and wont start. It has fuel going to the carbs and the fuel shutoff solenoids I hot wired to the battery. New spark plugs and battery all cylinders have spark and timing is correct but it refuses to start. It tries to sometimes but never actually starts. Does anybody have a diagram of the engine bay or wiring diagrams that can help? Need to know if I'm missing something . I will attach some pictures also.
Congratulations! Is your gasoline fresh? We could go through a whole list, but first thing I notice is the choke plates seem too far open for a cold engine. Then, you say you have fuel to the cabs, do you have fuel being squirted into the carb throat when you pump the throttle? Next, since you say your spark and timing is good, I would check compression, then vacuum leaks, including the brake booster. Good luck and let us know.
Tom
Congratulations! Is your gasoline fresh? We could go through a whole list, but first thing I notice is the choke plates seem too far open for a cold engine. Then, you say you have fuel to the cabs, do you have fuel being squirted into the carb throat when you pump the throttle? Next, since you say your spark and timing is good, I would check compression, then vacuum leaks, including the brake booster. Good luck and let us know.
Tom
Hello, it does have fresh gasoline and the chokes open that wide as soon as I turn the key. It only gets fuel to the carbs if I pour it through which is why I thought fuel shutoff solenoids but then I hotwired those to power and it still doesn't squirt into the carb. Could still be a fuel issue but I need to look around a little more as well as finish fixing wiring. Thanks
Congratulations! Is your gasoline fresh? We could go through a whole list, but first thing I notice is the choke plates seem too far open for a cold engine. Then, you say you have fuel to the cabs, do you have fuel being squirted into the carb throat when you pump the throttle? Next, since you say your spark and timing is good, I would check compression, then vacuum leaks, including the brake booster. Good luck and let us know.
Tom
So I've made a discovery that idk how I missed. fuel is not being sprayed into the bowl when I move the throttle.
Last edited by Dillbob; Jan 19, 2020 at 03:19 PM.
Reason: Jj
Unless it is quite warm out, I would not think the chokes should open that far. But first, you need to get fuel to the carbs. Not knowing where you are, is the fuel pump pumping fuel? After cranking, if you loosen the fuel inlet line/pipe to a carb, do you get fuel leaking out? Obviously, do not start a fire.
Tom
Unless it is quite warm out, I would not think the chokes should open that far. But first, you need to get fuel to the carbs. Not knowing where you are, is the fuel pump pumping fuel? After cranking, if you loosen the fuel inlet line/pipe to a carb, do you get fuel leaking out? Obviously, do not start a fire.
Tom
I am in idaho. It is getting quite a bit of fuel to the carbs. Just none squirting out when the throttle moves.
If you are getting fuel to the carbs, but none is squirting out when you pump the accelerator pump, it appears something is wrong in the carb. If there was fuel left in the carb and the car sat for awhile, the fuel may have gone bad and gummed up things in the carb, although usually it just evaporates without an issue. Either way, it may be time to remove the carbs, clean them out and replace all soft parts. But before that, you may wish to simply remove the carb top and see if there is fuel in the bowls and if they look dirty. The top comes off in two parts and I believe some of the screws are different lengths. To remove the tops, do not forget the center screw. It is reached down through the center threaded hole that the air cleaner mounting screw threads into. My 230/8 does not have fuel shutoff solenoids, but it sounds as if you are aware that they need to let fuel through.
Tom
Bob, do you have any updates for us? Did you get it running?
Tom
Hello,
I have been gone the past few days. I ended up ordering electronic ignition that should be here tomorrow and I plan on taking the carbs off to look around as well as replace the water pump as it's leaking. I just wish I had warmer weather to work in lol. I will keep you posted with what I find. Thanks!
Bob, do you have any updates for us? Did you get it running?
Tom
Well I got around to installing the electronic ignition, went with crane xr700 system and a new coil. After installing it and charging the battery the car started right up on starting fluid. But I do think I had 2 issues. I solved the no spark but after starting it only runs if I spray ether down the carbs. I've got fuel going to the carbs just not spraying into the bowl when I pump the gas. I was reading somewhere the zeniths have a fuel shutoff connected to power. Would you know where that might be? Also do you have any links to where I can find how to adjust idle on the carb? Thanks for the help.
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