Have been trying to correct an erratic idle in an ex-mod 109 with a 2.25/Zenith. Have rebuilt the carb, timing is ok, valves adjusted and no vacuum leaks. A friend mentioned the PCV valve (looks original and the diaphram is suspect) and thinking they were a few dollars went to order one, surprised (very) at the cost of a replacement PCV. Has anyone used an aftermarket, and if so do you have the manufacturer and part number? Thank you very much