I won a Johnson 18hp on ebay, but he said that it was a early 60's model. The price was at $151.00. He tells me now that it is a 57/58 model and is a pressure tank engine. He is giving me the option of getting out of the winning bid. I am wondering if this is still worth it. I don't have a pressure tank and it does not come with one. Should I still buy it and pick up a pressure tank when I can find one? It is supposed to be in running condition, but I won't be able to check without a tank. What do you think?