deere 65 engine options?

Well, those little engines use $20 batteries but if you insist on pull starting you can just not buy one. I think the 8hp and under engines will all fit as long as the crankshaft is the same diameter to fit your pullys. They generally all fit the same mounting holes regardless of brands and your aircleaner and mufflers are the next headache areas to watch for as well as cable routing for the throttle.

The 65 I used to have did have a battery and electric start, but no charging system at all! You just had to charge the battery with a charger every month or so.

Oh, If you just want a butt buggy for your son to putt around on, you can stick about anything in it and put a pully and belt to fit. I have an old 68 in a shed that I modified years ago for my little nephew to run around the yard on and I put a 3.5 briggs on it and a small pully to speed it up with. The little thing was a bit touchy to start out on in 5th gear without killing it, but it would fly once you cranked it up! You would stick with around the stock diameter for stock speeds. Course i don't know if you were wanting to mow still. The 68 didn't come with a deck for the $10 I got it for.