I have a Yard Man 8hp 26" blower from 1977, and it has been gradually losing forward speed over the past 3 years.
The symptom is inconsistent forward speed when I change in and out of a specific gear. So if I am in second and shift into reverse to reposition, going back into second usually has a different ground speed. This is most obvious in 5th, which is usually a brisk walk: this past weekend it was a normal pace. There is also "slip" of some sort, meaning going up a slope I lose forward speed. This blower used to be UNSTOPPABLE in first, so grippy it would drag me no matter how much resistance I put on it.
I changed the drive belt this past fall with a factory part. I changed the friction wheel about a year before that, cleaning the friction disk with brake cleaner (none touched the rubber wheel), and the disk was in great shape. This really leaves just couple things remaining: friction disk, play in the friction wheel positioner, friction plate to disk pressure, drive belt sheave on the engine crank shaft, idler belt tensioner.
Other things to check?
The symptom is inconsistent forward speed when I change in and out of a specific gear. So if I am in second and shift into reverse to reposition, going back into second usually has a different ground speed. This is most obvious in 5th, which is usually a brisk walk: this past weekend it was a normal pace. There is also "slip" of some sort, meaning going up a slope I lose forward speed. This blower used to be UNSTOPPABLE in first, so grippy it would drag me no matter how much resistance I put on it.
I changed the drive belt this past fall with a factory part. I changed the friction wheel about a year before that, cleaning the friction disk with brake cleaner (none touched the rubber wheel), and the disk was in great shape. This really leaves just couple things remaining: friction disk, play in the friction wheel positioner, friction plate to disk pressure, drive belt sheave on the engine crank shaft, idler belt tensioner.
Other things to check?