Just my opinion---
If you only use it for short distances, that is an awesome motor. I say that because it's slow. How can anyone think 250 for an incredibly reliable motor that will last 2 lifetimes would be a bad deal???
Now, MYSELF, I wouldn't pay that for it, but I like to collect them and have about a dozen, so I must confess I DO NOT need it. Don't tell my wife I said that, though.
It does have a shear pin so do a little research and ask some questions about it so you know how to use it. A 5.5hp OMC is about the most reliable motor ever built---just so you know. Especially if it has new coils.
Don't expect it to plane your boat, though--unless you weigh below 140 lbs. it's not going to happen.
And it will probably start the first or second pull on choke when it's 20 degrees outside--mine do.
Don't be scared of it because it's old. And don't get all upset when you run it in a bucket and it puts some oily crap in the water when you run it. All 2-strokes do that. If it bugs you, try the synthetic oil--it's more quickly biodegradable and doen'st make as much gunk.
Now, a guarantee for a year?? Heck, that's just crazy!!! I'd buy it just for that.

The fuel pump conversion is nice, too. You can get a cheapo walmart tank and be in business. Since you're only using it rarely, I'd take it out and run it in a trash can every so often to keep the carb clean and the water pump impeller from taking a set.
It's a good deal. Get it if you want it. And don't go out there cranking it every once in a while in the barrel in the yard just to see it run and because it's so easy to crank. I never did that with any of my new/old motors.

JBJ