I got an 86 318 with 1634 hours on it. It smokes on start up and does slowly burn oil. Takes me about 2 hours to mow the lawn and I have to add oil every few times mowing. Tractor runs pretty good but do get a slight surging around 1/4 throttle but that's about it. I've had the carb partially apart and pulled the float, needle, and pilot jet out and soaked up all the gas in the bowl and cleaned it out the best I could. Dumped seafoam in the bowl and let it sit a bit and put it back together and started it up and smoked pretty white till it burned the seafoam out lol. I do run it in the gas sometimes too to help clean the carb. I tried spraying carb cleaner around the intake gasket to check for leaks but engine rpm didn't seem to change so I'm assuming that's ok. Anyways, I guess what I'm wondering is do I re-ring it or new rings and pistons or just keep running it the way it is and if it craps out , repower it? I'd rather not spend over a grand on a full rebuild kit. Thanks in advance for any help.