2000 Posts and climbing!!!
Join Date: Apr 2016
Re: Deere D110 - piston moves but flywheel stuck
Track down the service manual for the engine (may be tricky to do, as it may be non-trivial to find the manufacturer's model info for the engine, as JD wants to sell you their version of the service manual (or get you to punt it to one of their dealers). Read through it, and then, take the engine apart and try to identify what has gone wrong.
At that point, you can decide if it looks like something you can do, or you want a shop to do part of the job (say, if something needs machining, or bearings pressed in/out) or you want a shop to do everything. It's also possible that something can be broken inside that makes it not worthwhile to repair the engine.
I find taking pictures of assemblies before/as I'm disassembling things to be very helpful, as the service manuals aren't always exactly clear on what goes where. In particular, the carb & choke linkages can be tricky to get right if you don't have pics of exactly how and where they go.
I also bag small parts that go together in a ziploc sandwich bag, with a label of what/where the parts are/go. And note, some parts should also be tracked where they come from (ie, the valvetrain, like valves, pushrods, lifters, rockers) [cylinder 1, intake, cylinder 1 exhaust, etc...].
If you are methodical about it, and have time, it's pretty straightforward to do. And don't be afraid to buy special tools as needed, as while they can be expensive, it's can also be expensive to get someone else to do it as well...