Her rig is likely original if she has closed body vs. open body turn buckles. All mine were original and mine is an 81. The closed bodies have several drawbacks. The turnbuckles must be lubricated to rotate freely and the closed ones gaul easily. I know this because my Marina wound a double kink in my back stay starting me on a replacement program early. I plan to at least replace the turnbuckles with open body turnbuckles shortly then do the rest of the shrouds when I drop the mast in a year or to do some major maintenance.
The one or two cylinder Yanmars are reliable, but do shake a lot at some RPM's. I was quite alarmed when I started mine for the first time LOL. Sounded like two guys driving a railroad spike! Look at the engine beds. Mine are really just a couple of beams bedded in epoxy putty instead of formed to the hull and tabbed in place with roven woving instead of fully encapsulated in fiberglass. Two of the tabs had separated from the beds, but they were easily reattached with epoxy.
Check the fittings that penetrate the hull from the inside. Any black or dark discoloration on the stainless nuts underneath is a sign of a potential deck leak. This might not be a major issue...most 30 year old boats will have some moisture in the deck during the survey. Check the chain plates especially thoroughly. Any sign of drips or stains on the wood around them could result in the need for a major bulk head repair. Fortunately the design of the boat lends itself to this repair as the panels the chain plates are bolted to are sacrificial and protect the main bulk head. I still had some damage to the main port bulk head though. See my post of the work that the previous owner had to do before I bought my boat on this site under "boat info" then "knowledgebase" ((if I recall correctly). If I had done a better job of matching the stain it would be virtually undetectable.
Check the alignment of the head door. Open it. There is a wooden stop on my boat across from the head door on the cabinet opposite it. My door hits the cabinet way before the stop. A few others have noted this and concluded that there either wasn't a block under the compression post under the mast (built into the port bulkhead) or the block, which would be wet by water passing down the head drain, has disintegrated. This is not a difficult repair and should not dissuade you from purchasing the boat. Just a negotiating point.
If there is staining of the sole in the galley it may be time to tighten or repack the rudder stuffing box. I finally figured that out after some help on this site and a following sea last year. Also note that some of the bolts involved in the rudder stuffing box area are not silicone bronze and may be rusty / degraded and need replacing. The sole in my boat has been sanded and repaired several times and the teak laminate is shot at this point. It is about $500 for teak veneered plywood plus time to repair.
The rudder post is solid stainless on my boat and my rudder is sound. This is a blessing as my last boat's rudder was saturated with water and the rudder post was a pipe, not solid. Solid is very reassuring.
I have a leak in the toe rail just aft of the bow pulpit in the vee berth. Again look for staining, this time of the polyester liner. The liner may be falling off the cabin roof inside, but this is not a difficult fix. All in all I like the fact that I can access the back of all my hardware and I like the polyester "mouse fur" liner versus none or a vinyl liner like I had in my last boat.
I have had my electric panel off and in general the wiring in the boat is decent and was not a concern.
Parts availability is decent, but you can't get a new head for the 2QM15, based on Gary's experience. I looked too and we also looked for a way to repair his cracked head, to no avail.
The good news is that engine access on the 9.2A is sweet compared to most 30 footers. I swear I could have mine on the dock in two hours flat if I had to. The only downside is that the engine cover is a little cumbersome to put back on the half hinges it is designed with, but that is a minor inconvenience at most.
Occasionally my 2QM15 won't start easily or at all. It doesn't like cold weather and lacks glow plugs. However, opening the engine cover and rigging a line to the cylinder pressure release allows you to get the engine spinning well. After it is doing so release the lever and it will then start. When it wouldn't start at all I replaced the cracked rubber starter button, which cost $20 and took five minutes. It still wouldn't start. We had a heavy dew that morning and had washed the boat down. I thought that perhaps things got damp. Jiggling the connections on the engine panel seemed to cure it and it hasn't happened again. However, posts on here alerted me to a known issue with this set up which can be cured by running a heavier gauge wire between the panel and starter. Not a big deal again. But the jobs on a good old boat start to add up for sure!
The encapsulated keel is great because there are no keel bolts to worry about, however, if you hit something significant with the keel you should either dive or pull the boat to check for keel integrity and to ensure you are not taking on water. A soft grounding isn't going to hurt anything, as the glass is quite thick. The downside to the set up is that the deep bilge is a pain to clean and the engine on the 9.2A is mounted right over it making pollution of the bilge inevitable. I put a disposable broiler pan under mine and a oil absorbing pad under the engine. I also put a reusable oil absorbing pad on a line so I can pull it up, wring it out and redeploy it easily. Given the potential fines for pollution I also put a bilge filter on my bilge pump hose. The bilge filter is about $100 including the element.
Whew...what else can I think of? Heavy crazing of the ports and hatches is common. All are pretty straightforward to fabricate and replace except for the companionway slider which the previous owner of my boat replaced. He said it was a significant challenge as there was machining of the plastic and then it had to be heated and curved.
Oh yeah! The aluminum water and fuel tanks will leak soon if they haven't been replaced and aren't leaking already. I think we have a big enough sample to say that decisively for 78-81's now.
That's enough for now.
Bob