I have a 1957 Willys CJ-5 with the straight 4 hurricane engine. Lately it has been idling very high and would like some guidance on how to fix it. After a cold start and the choke is fully back in, it'll idle very close to what should be normal. But after warm and driving it around, it will idle very fast. Last fall I put in new spark plugs, cleaned the entire air intake/oil bath assembly, and also flushed the oil; (drained old oil, filled with new oil, ran it for 30 minutes, drained again, then filled with additive and full synthetic.)