Funny, people are willing to throw out off-the-cuff advise without knowing anything about the boat. If you need to run from a 1985 boat at the first blush of problems that need fixing, you'll never get your boat. I bought a 20-year old boat with trepidation over the engine because of the way it looked - oil leak, rust, belt dust staining the engine compartment, hoses that looked sketchy and a few other things that made me uncomfortable. During sea trial she ran just fine during an hour cruise where we put her through some paces. That said, the first winter, I spent about $1,000 on new Yanmar parts and did a minor overhaul on my own.
If you can't replace those 5 items on your own, then you shouldn't buy a 40-year old boat. None of those sound like a deal breaker and if that is all that need fixing, I'd say that is remarkable. I'm not saying that the parts won't be pricey, but that's one of the reasons why a 40-year old boat is so cheap! DUH! If I was looking at a 40-year old boat, I would expect to replace the engine sometime soon, if not immediately. If I didn't have to, I'd consider it a bonus. Find out as much as you can about these supposed engine problems for sure. If the boat has been in use over the past several years, it can't be bad enough to run away from over the first sign of trouble.
Of course, if you don't have the time or inclination to deal with these things when you travel to Maine, it really doesn't make sense to look for a 40-year old boat in Maine when you live in Florida. I would agree with those that say a Maine boat is going to be in much better shape than a Florida boat so I get that part of the equation. Do you really think those 1980's boats in Florida would be free from blemishes? I don't. Anything that is close to 40 years and asking price in the low to mid 30's will have problems at least as daunting as the problems you find in that Maine boat. I suspect that part of the charm of that Maine boat is the opportunity (you might call it "necessity") to take a nice long trip on her.
I'd bet that you could get the Seller to address those engine issues and possibly even get a mechanic's report on the engine before you get to Maine. You may as well ask and consider it a condition of sale.