HC, CO2...

CO 0.5 - 1.0 CO2 13 - 16 HC 300 max O2 0.5 - 2.0

So the figures you have are fine. with something that old you are doing really well!! If the engine is running well and has good plugs etc. and the CO is in the right area then the HC will be OK and as the other two are related all should be well. Adjustment wise the mixture screw will change the CO. Everything else is largely determined by engine condition.

Nedavno Mrcheerful napisa:

So there is no need to, for example, screw in idle speed screw and screw out mixture screw or something?

I did look at Autodata (where you probably did get this numbers from), but it seems that it gives values for CO2 and O2 for almost every engine I checked (not too much I must admit).

as long as the idle speed is as specified 850 +-50 and the co is correct, and the general servicing and ignition timing is correct then all other figures will be ok

Nedavno Mrcheerful napisa:

Yes, idle speed is ~850 rpm, CO is 1, timing is set to spec (25 deg @ 2300 rpm), and all ignition components are in good condition.

While we are at it, I connected vacuum gauge to the inlet manifold, and it shows at idle IIRC ~20 in HG (it's in the green part of the scale).

But it fluctuates very fast ~0.5 in HG up, and ~0.5 in HG down. About 5 times /sec (roughly), the end of a needle is blurry.

Is it normal, or do I have something that needs adjusting?

That is normal depending more on the gauge/hose/connector position than anything wrong.

Nedavno Mrcheerful napisa:

OK, thank you.