My 1971 250 has twin carbs and one is loose. Where and how do I tighten it... from the bottom?

And where is the idle set screw? I can't seem to find it in the manual. Any help out there?

of late these carbs have been extensively discussed I'll pass on what was passed on to me. The mounting nuts are located awkwardly below the carbs they should need a 12mm wrench the 4 on the passenger side (assuming LH drive car) are easy to get at. The ones closest to the valve cover will require one on three things. 1 - a 12mm wrench cut off short (maybe 4" long anyone? I did option 2) and the stub end rounded and smoothed out. 2 - remove the valve cover and with great patience work the nuts 1/6 of a turn at a time. 3 - find the special Hazet tool #4531 made for the job, I recently discovered it in the last Spae-naur fastener catalogue#12 . The new catalogue doesn't list it. The tool is wrench, bent up 90 degrees with 3/8" square drive at the top, it looks cool but knowing Spae-naur they're no giveaway.

The Zenith carberettor setting manual can be found online at http://www.jaimekop.com. It has pics, diagrams and various ways to get your carbs tuned or FUBAR'd quickly. Keep in mind the engine will not run smoothly unless the carb flows are balanced.

...if there is one thing we're good at on this forum, it is giving advice on the Zeniths. Just be aware going in that they may have some problems not easily fixed. But no shortage of advice!

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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

I just called to get pricing on the tool I mentioned earlier. $67.95 (cdn$) or about $43 US and they show 16 pcs in stock. I suppose if you make a living doing this....

I LIKE my Zeniths. Buy a wrench and cut it to fit. 12mm if it has the original nuts ( or 13mm if they were changed by a previous owner. )
Good Luck,
Mark DiSilvestro
1972 250
1972 250C

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DrDKW

Debi:

When you tighten the nuts pull them up snug but don't try to really squeeze them down or you will probably crack the insulator blocks. They are phenolic and tend to crack or break at the carb stud hole easily of over stressed. If you use the "short" wrench, snug them using two fingers on the wrench - that should get you there.

Oh, don't bother to ask how I know that these insulator plates crack and/or break easily - thanks.

Dan

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Dan Taylor/ Tulsa, OK MBCA
'84 300D/'90 Jaguar XJ6/XJ40