Need advice on engine that has been sitting.
 

Previously healthy running 13b has been sitting outside wrapped up in a plastic tarp for a year and a half. Would you gamble on an install or say a rebuild is mandatory?

Pull the plugs and uncover intake and exhaust ports. Look inside the exhaust ports with a strong flashlight in a dark room. Rotate it by hand and feel for any kind of "hard spots" indicating rust or carbon.

definitely the moisture has gotten in it. like jeff said, get a flashlight and look inside it. probably can get alittle oil down in it and rotate it around in there. g/l with it.

i'd pull it apart. i personally don't trust used motors

What I would do (cheap method):

Inspect the apex seals to make sure that they are intact and moving freely against their springs. You can do this through the exhaust ports, and use an unsharpened pencil or something like that to push on them so you don't damage them. If you find any that are sticking, then try some Seafoam to get them moving again.

Once that is verified, then the only real risk beyond that is whether the coolant seals and oil control rings are deteriorated. Coolant seals can be "repaired" by using Alumaseal in the coolant (worked for me), and bad oil control rings can sometimes be "gotten by with" if you use Lucas in the oil.


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