Will turn on only if I wait for several hours

my friend spilled tea on his macbook then contacted me for help, i have disassembled his macbook, cleaned some spots on logic board, keyboard connector, trackpad from corrosion and it turned on, working flawless.

but if i turn off the macbook i have to wait for 5-10 hours to turn it back on

Restart procedure works flawless, problem occur only if i turn it off