Re: Outboards for Dummies - QD-20
It more than likely needs a carb rebuild. Outboard carbs are prone to collecting varnish and gunk if it sat at all, that's probably the case. Your main jets are probably the issue. Carb rebuild kits are pretty cheap and the procedure only takes a few minutes to perform. While you're at it, you should think about replacing the impeller too. On an old outboard like that, coils, plug wires, points kit, carb rebuild, and impeller are pretty standard fare after getting it.
Edit: Could also be a case of stuck rings, but i think that would translate into poor idle. Did you perform the seafoam decarb on it yet?