Aikosha 21 Day Striking Wall Clock - Japan

Aikosha 21 Day Striking Wall Clock. Measures approx 21” high, 10 1/4” wide and 4 3/4” deep. Case is in nice shape for age. Has a few marks in the finish here and there. Comes with winding key. It does run and strike, but it keeps stopping on me after about 15 minutes. I am not sure if I am doing something wrong, if it needs to be adjusted or just cleaned. Being sold as-is.