How to tune the carburetor and set the distributor timing |
CO adjustment - Gas analyzer - Timing light

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  • OVERALL DIFFICULTY INDEX: 3/10
  • IF YOU HAVE NO TOOLS, YOU PAY $250 TO GET THEM FOR THIS JOB
  • IF YOU HAVE NO EXPERIENCE YOU SPEND 2 HOURS TO CARRY OUT THIS JOB
  • RISKS RELATED TO EXHAUST GAS INHALATION.​
BEFORE YOU START
  • This requires the purchase of a timing light and a diy CO analyzer. 
  • The latter costs around $200 and is quite difficult to find in shops. Better to buy it online from our partners' store (see link further below)
  • You can still manage without the analyzer i.e. without knowing what the result would be. You can test drive the vehicle and check if all goes smooth. 
  • The below applies to vehicles equipped with electronic ignition. Distributors with a contact breaker should be first adjusted for dwell angle.

DISCLAIMER:
Our pictorials are of informative nature and do illustrate works carried out by ourselves at our own premises for our own use and satisfaction.
Readers who envisage to carry out similar works inspired by the below method shall do this at their own risks and liability.

Step 1: setting the distributor timing with a timing light

1- The ignition timing has to be set first. This requires a timing light.
2- You also need to know or find the place where you can read the timing setting. It is on the flywheel between engine and gearbox on transversal powertrains or on the crankshaft pulley.
3- Connect the high voltage wire of the timing light to the spark plug wire of cylinder no 1 i.e. the one nearby the gearbox.
4- Connect your timing light to the battery.


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5- Check in your vehicle's notice if the distributor vacuum hose has to be disconnected during the timing adjustment.
6- Loosen the distributor fixing nut enough to let you turn it by hand. Do not over loosen the nut.
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7- Start your engine, let it warm up and reach a steady idle speed. Lower the idle speed as much as you can while it remains steady. Point the timing light towards the timing indicator and rotate the distributor with the other hand until the timing mark on the flywheel matches the required setting indicated in your vehicle's manual. In this case [12 degrees + 2].   ​
Buy your timing strobe here:

Step 2: carburetor CO adjustment with a gas analyzer (tester)

8- Tighten the distributor nut and drive your vehicle for 2 km at least to make sure engine is really hot. Connect the CO analyzer with the probe still in clean air.
9- Let the reading float for a minute then calibrate it to the recommended value as indicated on the analyzer. Wait until it stabilizes to the recommended setting. 
10- Now introduce the probe into the exhaust.

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11- Tighten the mixture richness screw slowly and steadily until you feel the engine is losing its idle speed or it stalls. (If it stalls, loosen the screw 1/4 of a turn before attempting a restart).


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12- Loosen the screw 1/8 of a turn and check the CO reading. Such analyzers are not accurate enough to match the vehicle's CO setting. Just make sure it is the lowest possible between 0.5 and 1.5% and that such reading is steady for at least a minute. You can now pass the vehicle inspection. 
Buy your exhaust analyzer here:

See also our other carburetor fixing pictorials, and how to buy your exhaust analyzer from our partners' store: