My sons suzuki LT80 starts fine but but wants to stall out when I give it throttle

CHECK COMPRESSION ON ALL CYLINDERS

maybe some of both

The condition is call vapor lock.
Is there any missing heat shield?

======
Use a bottle of yellow HEET dry gas to remove any moisture problem in the fuel.

03 Suzuki Areio won't idle when hot??

If there is no engine codes like my 03 Areio 2.0 I simply cleaned the throttle body and adjusted the throttle cable when the engine was hot back to 800 rpms.. seems to be the fix. I'm suspecting the cable after 240k was a bit stretched and didn't give enough tension to the butterfly valve after it was up to operating temperature..

check for loose, cracked or disconnected vacuumn lines or connectors that are missing a vacunmn line.

do you have a clean metal to metal ground to begin with as well if it did run and throttle was fully open you may have fouled the plug'-s try leaving the plugs out to dry or replace them to begin with

sounds like trash in the carb clogging the main jet

Sounds like you are having a problem with the fuel injection on it. Take it to the dealer.

Install new sparkplugs. Activate choke. Do not touch throttle. Push starter button. Do not touch throttle. If bike stalls repeat until it stays running, then you may give it a little throttle. If I give my TL any throttle on start up it floods. It usually takes 2 or 3 tries where the bike starts then stalls before it stays running. DO NOT TOUCH THROTTLE UNTIL IT IDLES. THEN GENTLEY.

THe Carbs need to be pulled off and cleaned. If you keep on what your doing. You will burn a valve or a piston. It like leaning a torch out to cut metal.Alternator is probally a bad ground, are blowed fuse????