I have a 9.9 hp Tohatsu long shaft.
Here is what I would suggest:
* Spark plugs
* Gaskets and membrane for fuel pump
* Carb to intake gasket
(o-ring style; ordinarily these can be reused but they're small and cheap)
* Carb bowl gasket
* Fuel filter
, either complete assembly or bowl, seal, and screen
* internal fuel
lines and clips, can skip these if recently replaced
* Spare stop switch lanyard and clip
* Spare fuel line assembly from motor to tank, can skip if recently replaced
* Starter rope
(can skip if electric
start and the recoil is only used rarely)
* Gearcase drain plug
(easy to lose)
* Spare propshaft seal. Mine uses an assembly that includes the bearing. (easily damaged by fishing
line but may be an expensive spare)
washer, nut, and cotter pin
* Spare propeller
(big and expensive, skip if that's a problem)
* Water pump
impeller, housing, wear plate, shaft seal
, and rubber outlet washer
* Water pump
woodruff key (easy to lose)
Usually the carb can be cleaned, and it's unusual for them to fail on a regularly run motor, so I wouldn't necessarily bring a spare carb.
Ignition coils, module, etc are more likely to fail than the carb but make an expensive set of spares if you get everything. You need a puller and large wrench to get the flywheel off to replace them. Still good to have in case you need a shop in a remote
area to replace them.
If you depend on the alternator
I would carry a spare diode assembly.