1985 DT85 needs 3-4 idle air screw turns to idle properly

[lasersocks]

Recently I got my hands on a 1985 DT85. The motor was in impressive shape, except for some minor rough idle issues. I have now rebuilt all three carbs, got new spark plugs and used a spark tester to make sure there is a strong spark coming through the coils. When I compression tested, all three cylinders came out at 120. When I rebuilt the carbs, I noticed that all the idle screws were quite a few turns out, I thought that if I reset them to the manuals specification it might resolve the issue after the rebuild.

After rebuilding, the motor needed a lot of throttle to stay running, and would die lower than 1000 RPM and seemed to smoke more than I would expect. I assumed it was running rich, so I then adjusted the screws back out to 3-4 turns and it started to idle just fine with no smoke.

Main Question is: Is it okay to run it in the 3-4 turn configuration even if the manual states 1-1 1/2 turns, or is it a symptom of a bigger issue?

Secondary Question: I believe this is unrelated, but while debugging I noticed that one of the coils measures open circuit where it should be measuring 2.4 kOhm. It still produces a strong spark using a spark tester. How is this possible if it can't conduct to ground?

Thanks for the help!

[Solarman]

When rebuilding carbs, did you soak the carb body's, and "blow out" each passage/tiny little holes with compressed air before rebuilding?

It sounds like the tiny air passage-ways used to adj/mix air with the fuel at idle are blocked up, they each have to be blown out thoroughly before resetting air-fuel mixture screws to manual settings. The fuel at idle is a pre-set amount, when adjusting the idle air mixture screw, you are increasing (opening) the air mixture (more air - leaner); but when decreasing (closing) the air mixture (less air -richer), this is why i believe the air passages are blocked -up.

Good luck, post back on what you find out.