If it was not winterized... and you live where it gets very cold... it may have a cracked engine. (very common) If there is raw water in the jugs... when it freezes, the side of the jug will split open. Also... the pipe can split too.
If it was kept in a heated garage... then it's probably OK... but things can still be rusted inside. (Cylinders, crank, bearings, etc)
Either pay "Salvage" price for it... or take it on a LONG water trial. (like a full thank of fuel) I can bring a crap engine back to life long enough to sell it... but it doesn't mean it will hold together for long if the crank bearings are bad.
It could be just fine... but it could be junk too.
Good luck