Tohatsu mid sized 2-strokes are a bit agricultural, but that said their bullet-proof if properly maintained.
I've had my 60hp for a few years now, which is identical to the 70p mechanically without the throttle travel stop.
One weak point, and it's not exclusive to Tohatsu is electrical gremlins. The wiring isn't tinned, so there's a good chance if you expose copper wiring you'll see tell-tale green oxidisation which results in intermittent trim issues. One way around this is to splice in new tinned cable to the remote loom, or if you're feeling flush, to completely renew.
Given you don't know the history of the engine, then a proper flush with salt away is recommended. You can remove the thermostat for a closer look (you'll need a new gasket). Replace the impeller as a matter of course.
Only other niggles I've had was a failed starter motor, easily replaced, worn carbon brushes on trim motor, replaced with carbon brushes from a motorbike and springs from Hornby (as Tohatsu were looking for my still-beating heart as way of a ransom).
Lastly, be careful not to over torque spark plugs. The cylinder head was off mine due to a threaded plug, so noticed hairline spider web cracks on head due to heat, so alloy is brittle. You can get steel inserts if you're concerned.
Sula
