Just serviced my Tohatsu 60hp at the weekend. I had a fuel problem last year, in that the engine would cut out on one of my 25 litre fuel tanks. I opted to clean the inline fuel filter (on engine), replace fuel/water separator filter and install fuel pump diaphragm kit. Normally you'll get a warning if something is 'iffy'. I wouldn't normally replace the fuel pump... (on account of it being bleed'n expensive), but once you're aware of issue, then yes - replace.
Regards thermostat, the thermostat is probably okay, but remove to clean housing and renew gasket as a matter of course. Remember and lightly grease bolt threads.
If the engine is a pull start... then please replace starter cord too.