Howdy. Newly acquired car, the quest continues...

The car idles too high (about 1800 rpm) and I have yet to lube up the choke and carb.

I measured the timing at 23 deg #1 cyl BTDC, warm engine, choke in.
The engine compartment label states 7 deg BTDC. The car runs pretty smooth. Can my readings be right?

Does the vacuum hose to the distributor need to be disconnected to read the timing?

Also, the distributor body (new cap) is pretty old and I can find no ID or manufacturer numbers on it. What kind and model is it?

Also, does a high idle cause advanced timing or vice versa??

Thanks.

Hi. My 121 (a B18A with one ZS 175CDS)has high idle (1500 rpm) after a full overhaul. The culprit was air leaking between the carb and the manifold. I put a bit of gasket seal on that gasket and press a bit more the nuts.

Need to plug the tube coming from the distrib for timing measurement.

Also, old engines due wear has different timing settings. On 121s (with carbs, no damm computer gadgets) we advance timing up to feel pinging driving with load aboard (like go up to a hill), after it, we retard the timing a bit up to the point the pinging are gone.

¿Your dizzy are black/rusted or aluminium?

Happy Volving
--
Joaquin / Rojo 121 / Lima, Peru

Hello,

I have a B21A with a Z-S Carby and Automatic Transmission. There are 3 places to set Idle. The Set Screw by the Choke should be 0.5mm Gap, approximately 1 and 1/2 threads showing below the screw mounting bracket. The Brass Screw at 11 o'clock is the main one for setting idle . . . seems difficult and inaccurate to set. Very fiddly to get it just so. And, the Idle Trim Screw beside the Temperature Compensator should be roughly 1/4 turn out from all the way in, if that makes sense.

A high idle will start the centrifugal advance curve. Don't re-set the timing as you have to fix the idle first. The vacuum hoses to the distributor are supposed to be disconnected while setting the base timing.
Check for vacuum leaks all round. Pinch the hoses to the heater controls and the brake booster to confirm the engine isn't drawing air from them. If all of that seems fine, and the idle speed screw (small brass one in the intake manifold at about the 11:00 position) is seated, then the decel valve in the throttle plate may be hanging open. Remove the carb and solder it shut.