About the easiest TM going to service, engine just a basic air cooled so just change the oil, spark plugs & filter regularly
The pump change the oil yearly, the vacuum PD grease yearly ( they are pretty much bullet proof).
Only problem I've seen it the preheater which takes heat from the exhausted air can get clogged up with fibres, I just bypassed mine, if it runs, holds water pressure, does not leak, has not frozen, does not constantly dump water it should a winner