I just bought a new 930m and the deck slows down too much in high grass. You can tell the deck is slowing down before the engine starts to labor. My old m665 with the orginial 7 iron never did this, you would stall the motor down before the deck slowed any. The old m665 would out mow this brand new 930m which has a bigger engine and much higher blade tip speed. I looked at the spring that tensions the deck belt and it doesn't put much pressure on the belt. Has anybody else run into this problem?