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Tuneup, and Solex 34 PICT 3 Carburetor Adjustment


BEGIN WITH THE BASICS: Before you begin to adjust the carburetor, the valves, points, and timing should be set. Do it in this order, and you go from a cold engine to a warm one.

Setting the Valves -

Valve adjustment is always done with the engine cold - this means that it has been sitting overnight without running and is room temperature.

0.006 inches (.15 mm) is used on 71 and up engines, where the 34 PICT 3 was meant to live.

The aim is to set a gap that virtually disappears to zero when the engine is at operating temperature - expansion of metal and all that.

Adjusting the Points -

The points are adjusted to .016 inches (0.4 mm). Replace them if the contacts are pitted or the cam rubbing block is badly worn. Add a touch of grease to the cam lobs at the same time. Also pull off the rotor arm and take a look in the center of the shaft it rides on. If your distributor has a felt pad in there, put a FEW drops of oil on it to lubricate the distributor drive - don't overdo it though.

Adjusting the Timing -

The usual timing setting are:

  • 1300/1500/1600 engines with single vacuum distributor - 7.5BTDC. This is set static - engine off (or at idle with a timing light and the vacuum line disconnected).
  • 1300/1500/1600 engines using the double vacuum distributor - 5ATDC. This must be set using a timing light, with the engine idling and the vacuum lines connected so the retard line can pull in the 5ADTC (After TDC).

Check the Choke -

Now start the engine and warm it up. Take the air cleaner off the top of the carb and check that the choke valve is standing straight up. If it isn't, run the engine some more to make sure it's throughly warm, and check the choke butterfly again. If it is not standing vertical, the butterfly needs adjusting or fixing.

It's important to set the valves, points, timing and check the choke (in this order) before setting the carburetor, they all work together for a smooth running engine.

Setting the 34PICT/3 carburetor

  1. Engine warmed up, but switched off. The screw on the throttle arm, which faces to the rear of the car is called the Fast Idle Adjuster. This works with the choke to give a smooth idle on a cold engine. Unscrew the Fast Idle Adjuster (sits on the stepped cam), until it is clear of the stepped cam. Now screw it in until it JUST touches the very bottom of the stepped cam - NOT on any of the steps themselves. Now screw it in another 1/4 turn - no more. This sets the throttle butterfly open the required .004 inch, so you can use the Bypass screw (read on) to set the idle speed correctly. Now leave the Fast Idle Adjuster screw alone.
  2. Turn the Volume Control Screw (smaller screw in the side of the carby) in until it bottoms. GENTLY please - you don't want to open up the hole. Now unscrew it 2.5 turns. This is the starting setting.
  3. Start the engine and use the Bypass Screw (larger screw in the side of the carby) to set the idle at 850rpm (fast idle if you don't have a tacho). For a semi-auto car, use 900rpm.
  4. 4. Go back to the Volume Screw and adjust it slowly for the fastest idle. It should not be much outside the range of 2-3 turns ( turn in/out from the 2.5 basic setting). Then turn it very slowly IN until the revs drop by about 30rpm. If you don't have a tach, listen until you can just hear the revs start to drop, maybe as little as 1/8th turn.

  5. Now use the Bypass screw again to reset the idle speed to 850 rpm (900 for the semi-autos).
  6. That's it - you're done. If it still doesn't run right, something is worn or broken. Check the usual - air leaks, trash in carb, trash in fuel lines, coil dying, bad wires, bad etc.