Thanks. Think I've got that one, which seems to be Yanmars own and covers the 2 and 3 cylinder models too. Apparently quite a lot of errors, for example head gaskets reversed, so use with caution.

There is also supposed to be one for just the 1GM which is better, but I havn't found it yet.

I've also just got a Clymer "shop manual" which I think is probably their version of the Yanmar multi-model manual above, but have only skimmed the first chapter. Refers to "Phillips Screwdrivers with no mention of JIS, not a good sign.

In the 1960-80s cars were simple - the parsimonious and/or competent could fix their own cars. Unlike now, a decoke would be needed every 10-20k, and all components (steering, suspension, motors, etc etc) failed with depressing regularity.

Most jobs needed no more than a basic tool kit courtesy of Halfords + the odd special (eg: ball joint splitter)

The manuals, excellent though they were, started to become obsolete only when complete wiring diagrams began to cover more than a couple of pages. Once OBD ports become the principle way to diagnose problems, their day was just about done.

Modern cars may visit a garage but once a year for an MoT and service. Gone are the days of setting tappets, checking oil and diff oil levels, balancing carbs, greasing ball joints possibly every 3000 miles.