New Carb and PCV valve

[ndutton]

Let's see if it makes a difference first but if it does I'll leave the adjustment advice to those who have a PCV system and have been able to finesse the idle. My opinion is certainly in the minority but I am not a fan of a PCV system on a carbureted engine and depending on your results you may be describing exactly why I'm not a fan.

Your idle adjustment difficulty may well be a manifold vacuum leak and I have argued for years that a PCV system is in fact an intentionally designed vacuum leak so to me your symptom falls right in line.

[Chuck Dyck]

Carb

I will give it a try when I am at the boat this week.
Thanks
Chuck

[Sony2000]

I have a slightly different way to do the adjustment.
With the idle speed screw set not to touch the carb, throttle back, and the engine running, you begin to lean out the carb mixture screw. (counter clockwise). The engine is idling very slowly until the leaning will cause it to run rough. At this point screw in a 1/4 turn to get back your smooth idle.
Now screw in the idle speed screw, (raising the RPMs) to a point that the engine will go into gear and not stall. Or advance the throttle a little for higher RPM, and then set the speed screw to touch the carb body.

[hanleyclifford]

Thanks for all the help, the carb is in and I ran through the idle mix procedure but I can't get the idle less than 900.
Checked the linkage and the choke, they are good.
Could it be the new premium fuel I am using, 91 octane, the only fuel around here without ethanol?
Or, is it possible my timing is out?

Carburetor adjustment is actually the last item on the tune up procedure. First the timing and dwell must be on spec. Ref the PCV; if you mount the valve vertically you will have better results. Neil is right about the thing being an engineered vacuum leak. Under no circumstances should the thing be mounted in such a way that solid oil can get thru the valve into the airstream. The valve should be functioning in such a way that it allows the minimum passage consistent with holding a slightly negative pressure in the crankcase.