Well, I can't help you with your problem, but I can give you a bump. I am also having a similar issue. I can get my '82 DT85 to start-no problem. Keeping it running idle is my issue. But I can get it going, sort of, by revving up then throwing in gear (not good I know). But it still dies under any forward load. Now in reverse it is fine and will tach up nicely.
I have cleaned the carbs-and they are CLEAN! Checked fuel pump. Replaced fuel bulb. Air fuel screws. Cleaned the carbs. New gas. Ran carb cleaner through. Changed the plugs. Set the floats (best I know how from other member suggestions). Did I mention I cleaned the carbs???
OK. So my issue is somewhat the same. I can put it on ears and 'Make it' run. I have my kid start it while I stand by. Then control it with the spark advance lever and choke. It runs smooth at 2200-2500 RPMs (again, I know, not good on ears). But if I release the advance and return the control lever to idle, it will cut out. SO I was hoping for some ideas before I spend big money trying to get someone to fix this thing.
