You can source from Tohatsu supplier. I use Gaelforce Marine in Inverness. They order direct from Tohatsu. Shipping charges are in region of £6 (UK) even for washer, so order everything you need at the same time. I've also used Ribshop who are excellent. Rib - inflatable boat & outboard parts, repair & service centre
To remove drain-plug, strike the head using a blunt-end chisel with a light hammer a couple of times. These drain plugs are easily damaged because people use the wrong tools to tighten. Use a decent flat-head screwdriver that fits the plug slot neatly. You can also use a pair of Draper adjustable grips on the flat-end driver screw driver for extra torque while leaning into it.
Fit new fibre washers on the drain and fill plugs. Part number: 332-60006-0.
Drain and fill plugs are part number: 332-60005-2. Trim tab is part number: 3C8-60217-1
These are parts for Tohatsu MD40-50 2-strokes. Double check with dealer just in case.