on *:join:#channel:{ dolimit }
on *:part:#channel:{ timerlimit off }
on *:quit:{ timerlimit off }
alias dolimit {
timerlimit 0 120 mode #channel +l $calc($nick(#channel,0) + 2)
}
the above will check every 2 minutes while you remain in the channel and halt the timer when you part or quit. replace ALL #channel's with the channel you wish it to run on of course
hope it helps - cheers