I have a club cadet riding mower probably about 8 years old. Been a great mower however when I try to go backwards now it is really slow and will not go up a hill. Any ideas as to what the causes

SOURCE: engine drags while trying to start

It may be a problem with the camshaft-compression release. Some of the Briggs & Stratton models had a weak spring on the compression release whis is parts of the camshaft. you may also want tocheck that all wires are clean and tight. Also if it's a over head valve model check the valve clearance.

SOURCE: 2007 Toro LX 425 Riding Mower, slow cranking.

check the starter see if it is going bad or not?

SOURCE: murray riding lawn mower

Nix on safety switch. If it was a safety switch, you would not hear a click when you turned the key to start.. There would be no power going to the solenoid. However, if your engine has the fuel shutoff solenoid beneath the carb bowl, it will make a faint click when you just turn the key to the 'on' position. Probably as thabrain says, a bad solenoid.

SOURCE: engine on riding lawn mower surging

Dirty air cleaner.

Clogged fuel filter.

Replace or clean both...

SOURCE: Cub Cadet 2166 series. Mower will not engage.

Unfortunately, the circuit is a little complicated - it involves the "PTO switch" (the switch you pull on to engage the mower), a "reverse switch" that senses if you've put the mower in reverse, and a relay operated by the reverse switch. The reverse switch is there to disengage the blades if you try to reverse while mowing. A failure in any of those items, or the connectors and wiring between them, will prevent the blades from engaging. Unless you want to "shotgun it" and replace parts one-by-one on a guess (which many repairmen to do save time, but at your expense) you need to use an ohmmeter or test light to trace and isolate where the failure is.