i want to buy this quad from a guy but it is overheating, what could be the problem?also the electric start does not work and it is hard the get into 4wd? could it need tightening?

 

is it auto or manual, if its hard to engage in 4wd,if the shifter is push or pull on the fender, the fender may be cracked and its just pushing on fender, Starter problems could be bad battery cables, bad battery, or starter shot.Over heating, is it liquid cool? if it is look to see if radiator is plugged or thermostat stuck on it, if not liquid cool, check the fins on the head to make sure there not plugged with anything

 

Also on the overheating question. The cooling fan could be bad. It happened to mine on the trail. The only way I could keep it cool was run it in fast , short bursts then cool down for a little while until I got home.

 

Adamsquad - I had a 2000 500 auto. The fan was on from the moment I turned the key. If the machine is overheating and the fan is not on , I would first check the fuse,if I recall correctly they are located under the seat. The 2000 500 auto had 25-10-12 tires up front which made it steer very heavy. I dont think you will enjoy it.
At times I had a hard time engaging the 4wd. Don't think you will enjoy an old school machine. Save some more money and look further

 

Regarding overheating, as others have suggested start with the easy, obvious things first. They're easier to check and less costly.

1) Thoroughly clean the radiator (mud/dirt/crud caked in the cooling fins)
2) When the engine gets hot does the fan come on? Fan? Fuses?
3) Is the antifreeze/water getting to the radiator? Thermostat sticking or needs replacement. Is the radiator cap holding pressure? Worn or faulty water pump?

My only experience with over-heating was on my 1998 AC 500 Manual. The dealer checked everything. He installed a new thermostat. My 98 came stock with a 170 or 175 deg.F thermostat. The 97 Cat had a lower temp thermostat (160 or 165 F). We installed the lower 1997 thermostat in my 98. That cured the problem and ran fine for next 5 years.

Good luck.