Setting CO on 930 in VA

[scphelps1]

I know this has been covered, but I still can not find the adjustment screw to adjust the mixture on the fuel distributor. Is it a different screw than the spring-loaded one? The pictures/descriptions I have seen are for 911's. Is there any difference to the 930's location?

Also, does anyone in the Central VA area have a CO tester? I called Crown Porsche (local dealer) and they don't even have one! They say there isn't enough of a demand to warrant keeping one in their tool inventory!

Should fuel pressure on an adjustable WUR be set before attempting to get the CO/idle correct?

Thank you for any insight.
Clayton

[john walker's workshop]

adjusting the WUR for good cold running doesn't effect the warm pressure, as long as you don't get it way too rich w/cold.
the CO adjuster IS the spring loaded allen screw between the fuel dist and sensor plate, visible just to the right of the curve of the air filter housing. it needs to be pushed down to engage the allen screw on the sensor plate arm, then turned.

[scphelps1]

Thanks John

What do you set the CO at for this car? In Bruce Anderson's book I see the specs for the '79 are 2.5+/- 0.5 and the 77-78's are 2.0-4.0. What would you recommend for a 79? Also, what value should the WUR be set for, cold?

Thanks
Clayton

[john walker's workshop]

930s can be set to 3.5-4% for best idle and low end performance. that's with the air pump hose clamped as you do the adjustment, if it's still there. same with the later ones, (and leave the oxy sensor disconnected also).
the WUR usually works best at a cold beginning pressure of .8-1.0 bar. more than that, and it's doggy thru warmup. less that that and it's too rich and suffers surging and low idle, maybe black smoke too.