I have had a 318 for about 5 years and a 332 for past 2 seasons. Diesel is the way to go. My 318 actually looks better but has 1500 hours and burns a little oil. I looked at re-powering with a Vanguard or Kohler but you are right it would cost more than the $1500 I bought it for. The old Onan can really lug though and I worked the ground up on my acreage very nicely with it. It's too bad the rebuild is so expensive (Onan/Cummins won't sell as a kit) otherwise I would keep them both. The 332 only has about 1100 hrs and should be a 3000 hr motor I hope. It runs like a top and uses much less fuel maybe a 1/3 less. I want to get it repainted and sell the 318 since I really don't need two of them unless I could find the front loader but they are hard to come by. Much more common on the newer garden tractors than this vintage.