I just recently bought a '79 tuffy 15 footer, witch is fiberglass, kind of on impulse. I only have a 6hp motor. I found a 20hp Johnson for $300, and it is a ways away. All I was told is that it is in great shape for it's age. Any input would be great, thanks.

if you dont want it and its near me, I'll buy it.  he-he.

from what i know, 300 is pretty cheap, new 20's are running 2000.00 or better. i am looking for a 20 also, and wouldnt passs on that deal. get some pictures of it running, and with the cover off so you can see the Hoses and wires.

i dont know where you live, but i did contact a guy in TN that is willing to trade my 9.9 plus cash for a 25hp.

I think it would have to be in excellent condition to worth that.  $200 - $250 would be a much more realistic price.   Be sure you check the oil in the lower unit and see if it's milky.  Those are very prone to leak after they get a little age on them.   There's an O-ring under a brass bushing that's the main cause of the leak.

Do a compression test on the motor also.   I bought a 73 25hp remote start with controls last year for $50.  The only thing wrong with it was the lower unit leaked.