car runs at idle when in ingauged in gear car dies. what screw to adjust carb

[jessiepimentel]

my 1973 datsun 510 has a slight problem.my car takes a long time to start but when it does start i have a problem when i take the car from park to drive it stalls. i have no idea why. i would also like to know what screw do you adjust to tune the carb.

[datzenmike]

Not much info.... original carb or weber swap? If so new or POS? Header?, burn oil?, compression checked? any mods?

 

 

You need a good 16 to 18 inches of vacuum for it to idle well.

 

Check the valve lash. Tight valves will often leak vacuum or compression causing a poor idle.

 

Check ignition timing. The spark should be advanced to 12 degrees BTDC so that the hot expanding gasses reach their peak pressure at about 15 degrees after TDC and give a maximum push down on the decending piston. Too late and the pressure is chasing the piston.

 

Check plugs and wires, cap, rotor and points. You need good spark delivered to the plugs.  

 

Is your choke working as it should?

 

Look for loose, missing, cracked vacuum hoses.

 

Grab carb and twist it. Does it move? Loose mounting bolts will cause a vacuum leak. Is this the original carb?

 

Does it overheat? Use coolant and need topping upevery week?

[banzai510(hainz)]

Im thinking the dist is off(dissy swap) or the oil pump spindal off during a rebuild timming chain install.

this would be obvious when cking with that new timming light you have.

 

rest mike answered

 

 

if car runs at idle YOU DONT NEED TO ADJUST the carb.

 

If it idles there is more than likely NO vaccum leaks.

 

 

Is this a automatic??????????sounds like it. a automatic will tune a little different but close to the same.

 

 

read everything on olddatsuns.com the tech section.

[ggzilla]

if car runs at idle YOU NEED TO ADJUST the carb. It will idle if its too lean, but will die as soon as a load is put on it.

 

Adjust idle speed screw to 750 rpm. Then adjust idle mixture to beat lean idle.