YA640 Trips GFCI

Hi all.
My YS640 trips the GFCI breaker about five minutes after I turn it on. It worked well in past seasons. I'm using the same outlet as in the past, but tried others, including a much newer one, but the have the same problem. Any suggestions?
Thanks so much.
My YS640 trips the GFCI breaker about five minutes after I turn it on. It worked well in past seasons. I'm using the same outlet as in the past, but tried others, including a much newer one, but the have the same problem. Any suggestions?
Thanks so much.