Hey CTH,

I'm not sure I follow the vacuum modulator. Yes I do have an AT. At the rear of the intake, under the accessories port right?, is a metal tube that routes under the firewall. I don't see a modulator where you mentioned.

Ok. Venturies look fine. Last night I spent quite a bit of time readjusting everything from timing to balance and now she's running at 900 RPM idle and 700 in gear . she still has trouble going uphills and starting. Vaccum is still 17"

No I don't have 2 hoods and 2 meters. I just use the one and go back and forth.

The port between the carbs is open.

I'm not sure what the neutral and out of way settings are. I have the Zenith carbs that came with the later models. These are 42/35 as oposed to the 45/35. They do not have the idle vents and do have the idle stop solenoids.

Hi all,

I was doing some research around the net, and I found a recomendation for vehicles having trouble starting, moving... like I am is to advance the timing.

So I moved the distributor about .5" counter clockwise which bumped my timing from 7' to 12'. Put her in reverse backed up a little from my driveway, put her in D, and plenty of power goingo up the ~30' hill.

Now before I do any damage, any problems running her at 12' at 900RPM no vacuum?

Is the situation that it will idle OK at 800 in Park (you mentioned this about timing), but then dies in gear? What vacuum are you getting at 800?

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Hey Chuck,

Looks like the stalling in gear resolved last night when I redid all the settings on the carb. I still had an issue where it would bog down when starting from a complete stop and going uphill. I had set the timing to 7' w/o vacuum. I just bumped it up to 12' no vacuum and she's running much better.

I'm wondering if 12' is OK and will not cause catastrophic failure...

Thanks for your help...

George

I usually run my timing at whatever the plate on the radiator mount says, maybe a few degress advanced.

If you have to go much beyond a few degress either way, something is still wrong.

A slightly off the wall though comes to mind. Could it be that you have the firing order correct but have the plug wires off by one? Or maybe a wire or two out of order?

There should be a mark on the distributor for number one. It is on the rim and maybe near one of the clamps for the cap. With number one on the compression stroke, the rotor will line up with the mark and the number on tower on the cap. On the exhaust stroke the rotor will be 180' out.

Michael

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Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120

Hey Michael,

No, I'm good on that one. The plate says 4 ATDC but my emmissions dashpot is shot, so I've re-plumbed it so that advance is always on. Hense the timing can't be what's on the plate.

I'm looking at my Haynes manual, and it shows that my engine model is a 130v the same as the 280S/8. They have several timing ranges

12' BTDC no vac on a standard compression
15' BTDC w/ Vac on a low compression

I beleive I have a low compression 130.923 casting. It does sound like I'm in range...

Dang!

You've stumped this chump.

Michael

__________________
Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120

Hey Michael,

Ithink I've got most of it. Ok. Drove it back and forth to work, night and day! WOW. There is still just a bit of hesitation when you jam on the gas. Don't know if any of these cars "peeled" out.

I checked the timing and at 3K RPM no vac I'm at exactly 30' advance. at idle 825 RPM I'm at 15' advance w/o vac. over the next few days I'll try bumping the timing by 2' each way and see if there is any improvement.

now I need to rifle through the manual and see if there is anything about testing the vacuum secondairies. They don't appear to open. I know for a fact the did a few months ago.

With the engine off I moved the throttle all the way back and pushed a dowel down to make sure they where not seized. and they arn't. Anybody know what hte lifespan for those diaphragms are?

Thanks again to everybody for their help.

George