Needs choke for minutes until warm up

[38racing]

Tecumseh ov490 on an mtd rider. History is dumpster drop a couple years ago that I refreshed and church sold it to local guy. Two or three summers use but last summer forward gear went. I gave him a replacement for last summer. I fixed the gear and he's interested in using it again. I decided to check it over again. Running fine was my recollection but I noticed delayed starting and would sometimes spin backwards as it stopped. So I checked valve clearance. Intake fine at the .004 but exhaust was .009 so I set to .004. Now I'm finding that cranks a tad longer than some engines before starting ( might have been like that before) . When it starts though if I move choke off it starts to stall. I have to keep it choked various amounts for about 2 minutes after which it runs perfectly smooth. No issue cutting grass with it. Usually a bad idle circuit causes surge to stay in off load state. I pulled main jet and it's fully clear. I'm not excited about pulling carb for doing idle circuit since all seems fine after warm up. Could closing the exhaust clearance to spec have created this.