You don't have enough info on your motor for many of to even know how to start advising you.
You have a very old model there.
I get that it's new to you so you have to start way back with the basics. Did you do a compression test? Was it running well before you bought it? When was it last running good (or at all for that matter).
If it's been sitting for a while there may be no end of problems. Perhaps it was worn out and sitting long before you took possession of it.
So you can start it then what?
You increase the throttle and it doesn't pick up in rpms? or you had it in the water and it just won't push?
Sorry, just don't have enough in your post to even point you in any kind of direction at this point beyond "check the compression first". If the rings are worn out or the cylinders are a little toasted you either need to rule that in/out first before moving on to anything else.
