1985 ATC 70... stalls once warmed up?

[RideRedFan]

Hi guys... we have a 70 that starts like a piece of cake. No choke, first pull. (my 6 and 8 y/o boys can both start it once it's been sitting overnight or longer) They run it for maybe 15 - 20 mins and then it starts to bog and just dies. I can't even start it myself once it stalls out. They are running it at a pretty good pace so it's getting air (not overheating) The next morning it starts on first pull again and runs like a new one. The tank is getting plenty of air, the plug is good... I'm beginning to think it's something electrical, but I'm just not that great on electrical stuff. Any ideas? Thanks in advance. Jeff

[Autophysn]

sounds like a dirty main jet to me, or simple dirt in the carb period, but as for electrical? Does it back fire? Also check your air cleaner, it may be coming apart and releasing particles into the carb.

When it warms up and you can not start it, check for spark then. Maybe the mag is giving out?????? Just a thought, but I would start at the carb

Replace the spark plug just for sh^ts and giggles. Mine gave me hell similar to that once.

[BOBALOO]

next time it does that check to see if the gas cap is venting by taking it off. If you hear a whoosh sound it is not venting correctly but should start back up. I'd think it would do this sooner than 20 min though. Sounds like something electrical, possibly an ignition coil.

[CRAZY70MAN]

check magneto. Has to be clean, may have dirt or small oil leak at one of the seals or stator plate. Take off and clean with carb cleaner. You may want to drain tank and look at petcock filter also? Last , like the others said, carb problems.... good luck. on 3 eatin'4.........mad triken to all!!!

[dizasterzrfun69]

points and condenser