One of the easy things to check out on the 18xx models is the big things that are easy to see. Look at the bottom of the tranny for any leaks. Check out the rear wheel axle area for oil seal leaks. Look at the front of the engine below the PTO for caked on oil from a seal leak behind the PTO. While sitting still turn the wheel back and forth without turning the tires to see how much play there is in the steering gear. Don't buy into the old "It just needs adjusting" crap. At the age of these things the steering gear is probably shot. I believe the 1812 does not have hydraulic deck lift so that should be easy to check out by simply pulling the lever back and forth to make sure it works. On the engine rebuild the owner should have a detailed list of all parts and labor that was put into it. If not then I would not believe that it was rebuilt. Run it and make sure the hour meter is working and that the exhaust is not smoking. Listen to the engine at idle and at full throttle and then do the same thing with the PTO and the deck running. There should not be a big increase in noise. If there is then you will probably need some new spindles soon. If the deck has belt guards on it ask the owner to take them off so that you can see the condition of the deck innards. Check the amp meter for positive indication and make sure the brake safety switch is working by trying to start it with the parking brake off. Any ONE of these is not a deal breaker but more than a couple should lower the price by a good bit or make you walk away. Good luck.
