Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

My 10-12 year old Snapper I 722 runs like a champ but I noticed that I was not so self propelled anymore in the lowest gear (a good gear to use with the deep, wet snow last weekend here in Minnesota). 
Anyway, more recently, it seems I'm losing power on the second to the lowest gear.  I can get it to engage if I nurse it but it's not reliable.   I'm detecting a theme and assume it is just a matter of time until
third goes.  I've done oil changes, lubes, plug and muffler replacements but have never opened the chassis.  Is this a case of needing to adjust something?  Replace a belt or two? 
Can a DIY guy do this or should it go to a shop?

Since you are asking about "gears" you are referring to the traction system.

The way that works is that there is a pulley on the engine that connects to another pulley via a belt. the second pulley is connected to the rest of the traction system. The belt is supposed to be tensioned so that when the engine is on the pulleys are turning. There is no clutch effect as there is with the auger system.

I haven't looked inside the traction system so I may have things reversed slightly ( which comes first the friction disk of the friction wheel?)

The traction system is a series of gears that connect to a large flat disk that rotates as long as the engine is on. The flat of the disk is parrallel to the axis of the axle that the wheels are attached to. There is a rubber edged wheel that is mounted on a splined ( grooved) shaft that can pivot and cause the rubber to press against the spinning disk. When you shift the "gear" leaver you are moving the rubber edged wheel and the splined shaft back and forth. This changes where the friction wheel will touch the friction disk when you engage the traction system control. If the wheel is close to the centre of the disk then you go slow, if its close to the edge you go fast. The interesting thing is that if the wheel goes past the centre of the disk then you will be in reverse. The splines on the shaft have a gear on them that stays in the same position as the shaft and fiction wheel move side to side. This gear connects to the gear on the wheel axle via a chain whose tension is supposed to be tight whenever the friction wheel is pivoted onto the friction disk.

What does this mean? Well first of all when you "change gears" you aren't, you are changing the position of the friction wheel, none of the gears are changing. However the ratio of RPM at the engine to RPM at the wheels does change.

Now according to your problem description, the two most likely causes are:

1. Traction system belt is old and slipping, it will slip most noticably when you are in "low gear" since that's when the system is transmitting the most torque;
2. The friction wheel has finally worn out.

I've done both and the belt replacement is a bit easier so I'd start with that, after 10-12 years it doesn't owe you anything. It would be a good idea to renew the auger belt as well since you have to partially remove it to get at the traction belt.

Once the belts are replaced you can test to see if the problem is fixed, if not then the friction wheel is the next thing to check.

are the wheels worn out? because my lawn mower wheels were warn out and once i replaced it worked better