My 92 I recently bought has been having idling issues. I bought it and it wouldn't even run unless it was fully choked. I pulled apart the carb and rebuilt it. Night and day difference. I replaced the boots between the carb and the engine and the air box. I also cleaned the fuel tank and added an inline filter. Today I changed the oil, filter, and spark plug. I noticed a difference but it will still only idle for about 5-10 minutes max and then dies. It seems to struggle most of that time too. I also should note I adjusted the mixture screw to the factory 2 1/2 turns out. I live in Utah around 4500 ft above sea level. Could being slightly out of mixture be the problem of this? It seems more like it's struggling for fuel than air but you would think at my elevation it would be the other way around?