Homelite Weed Wacker will not stay running

[jtfoxman]

Hi everyone.
I got sick of letting my neighbor borrow my weed wacker so I offered to look at his for him and see if I can get it to stay running. He borrows everything else so I don't mind since I get everything back but he is borrowing it every week and it's becoming a pain. It is a Homelite 25cc with the numbers SH2025UB24RA and EM 08652-01 on it. No other id's that I can find.
He put straight gas in it and seized it. I couldn't even pull the cord to turn it over. I took it apart, filled with the proper mixture and now I can turn it over it just won't stay running. I primed it at full choke and it attempts to turn over. I can start it at half choke and it will stay running but only if I feather the throttle a little and after a few minutes it will stay running, but once I close the choke it instantly dies. I removed the bulb and primed it and it is receiving fuel and spark. I tried adjusting the idle screw to every position available and still nothing.
Anyone have any ideas where to start?

[HayZee518]

look at the rear gasket and gasket plate. straight gas dissolves any sealant used there. if the crankcase is sucking air, anywhere around that gasket the unit won't stay running because the air/gas mixture isn't right. with the gasket sealed proper vacuum is maintained and gas is sucked up through the "dangler" and into the carb. there's no float just the rubber diaphragm connected to the needle valve.

[jtfoxman]

Thanks for the advice. I'll look into that.