I started up my B2630 yesterday no problem. I drove to mow my field. When driving there in the road I thought it seemed like it was not moving as fast as usual. When I got there I engaged the PTO for the mid mount mower. The engine slowed way down and then died. I could not get it started after that. I towed it back to my garage. Any ideas? It seems like it might be connected to the engine not operating as fast as normal.