I have a 2004 bruin 350 that has been in storage for several years when I started it it wouldn't idle without half choke but would do it nice and smooth and it would only get to about half throttle so it had no power I cleaned the carb and it has full throttle now but it won't idle I think it's at the right Rpms and it will idle for a minute then die then when I start it again it might idle for a few seconds then die I just can't figure it out cleaned everything and if I press throttle in it runs great

 

I haven't had the problem myself but Yams are known for the rubber inlet manifold splitting and letting air in. Most likely time for it to happen is when you remove the carb, so it is worth checking. While you have it off again, check you have rebuilt the carb right. It is also possible you have an electrical problem. With engine running, check it is charging and the voltage doesn't get over 15V. If it isn't that, it may be the coil, CDI or pick up coil breaking down. If it is electrical, it may be cheaper to take it to a Yam agent, as parts are expensive and they will know that 350 engine inside out.