Is there any good detailed information on tuning a 1965 190C?

It has new plugs, a rebuilt carb, new fuel tank, lines, pump and
filters. Had the heads rebuilt. It has 105 to 110 pounds
compression in each cylinder. Idle mixture is 1 3/4 turns out and
it seems to run best when the idling jet is currently 2 to 2.5 turns
out. With the idling jet all the way in it hesitates at half
throttle and wants to stall, unless the choke is out a bit.

Also the muffler is old and needs replaced. Could some of these symtoms be due to low back pressure?

Would appreciate any guidance.

Gary Landrio

If the car idles good with the idle screw 2 turns out, leave it there. Why do you want to screw it in? The car can't get any idle fuel that way and closing the choke only reduces the air to match the available fuel. Does the car perform well otherwise?

Peter

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Auto Zentral Ltd.

Ok, but the engine still misses at idle and all speeds. What else should I check that I have not already tried?

I would start looking for vacuum leaks.

How are the plug wires?

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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

OK now it's time to start with the basics. I'd check valve adjustment first. As that aluminum head expands, valve lash can diminish. I'd then check manifold vacuum at idle. Then I would check dwell and timing through the whole curve. I would also check all the electrical connections in the ignition circuit. A loose connector can cause the problems you describe. I wouldn't spend much time looking at carburation.Defective plug wires could also be the problem. If you have a timing light, you can use it as a scope by hooking it up to each plug wire and looking for a skip.

Peter

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