[geezer#99]

Excellent advice Marine!
I might add that if it won't idle down to 700 rpm, just increase the timing a little at a time until it will idle lower. To do this don't loosen the distributor completely. Leave it a little snug and move it slightly. It likely won't take much.
Then set your timing.
10 degrees is a good place to start.
Your motor might like more but experiment with that later once you get it to stay running when you pop it into gear.

Another thing to remember is the elevation where you live. Just like Marine-58's motor, your motor will be happier with more timing than is usually used at sea level.