I have a Hayward 'Aqua Critter' (a.k.a. Aqua Bug) above ground automatic pool cleaner that generally seems to be in good working order. However, it only turns counter-clockwise, with very little forward motion...so it usually remains in the center of the pool. My understanding is that it should turn both Left and Right, as well as move forward. Any ideas as to what may be limiting its movement, or how I can fix it? Thanks.