I have a 149 that did the same thing. I repaired it myself with some parts from one of the vendors on here. You will find the trunnion under the seat after taking off the rear fenders. It is not a hard job, and the tractor runs like new. There is a video of this work on here, not sure where but you are looking for a repair of the trunnion. Good luck.Yes, I know someone here had this problem. The F/W lever controls speed on the left of the steering column by adjusting the hydrostatic transmission through a linkage that runs under the cover in front of the seat. My 149 will randomly accelerate without any touch to the control. On Sunday, I mowed my lawn for the first time this year, and I adequately compensated for the random acceleration by either pulling the lever back and gingerly starting forward again or stomping on the brake (which actually just locks the Hydrostatic into Nuetral). However, the 149 picked a turn as I was finishing the lawn to accelerate and threw me off the tractor before my 65 year old reflexes kicked in. My wife is still making fun of me for this! The 149 headed off into the woods and landed on its nose after diving off a 10 foot embankment on the edge of the lawn. I hauled it back up with my Jeep and it restarted right up. I drove it to the front and parked it. I would really like to fix this. Now I've heard that what keeps the speed constant is some kind of bushing that by friction prevents the lever from moving. Where is this bushing? It would make sense that it is in the steering column assembly, but someone suggested to me that the bushing is in the linkages under the cover in front of the seat, that I should look there. I can make a new bushing and put it in, but I'm famous for taking off too many parts unneccesarily. Hopefully, someone here can let me know the best way to access the bushing and replace it.
It's an original 1974 IH Cub Cadet 149 with a Kohler engine.
Here's a picture of it sitting on its nose in the woods below my yard. Remember any modern lawn tractor made of plastic would have been pretty heavily damaged. The 149 is completely unscathed (except for the rusty old hinge on the hood and one headlight). So proud of my 149.View attachment 143401