Clean inside neglected engine before starting it?

[RyRes]

I just picked up a kart from Craigslist and, before today, I had zero experience with engines.

The engine is a Predator 212, it was advertised as not running and they said it had been sitting for a couple years. Also, the air box is missing and who knows if they were running the kart that way. I pulled the carburetor away from the engine and while tipping it a little, it appeared that water poured out (from the bell?) along with a little tree bark.

I disassembled the carburetor and cleaned it. It was less degraded inside than I expected until I got to the jet (photo attached) but even that seemed to clean up okay. With the carburetor off by glancing in the air intake side of the engine, I didn't see much rust (photo attached). While checking the oil level, that smelled clearly of gas. Then, I took off the exhaust and, by glancing in the exhaust side of the engine, there was a little rust around the valves (photo attached). Sorry about the photos, it was tough to get the light in the engine and the camera to focus in the right place.

Seeing the clogged jet, rust near valves, and gas in the oil got me wondering...how much cleaning is enough before pulling the cord? Would those of you with experience clean inside an engine with an unknown history anyway before trying to start it even if the carburetor, oil, and cylinder head had looked okay?

I'll get the procedure for cleaning up the inside of my neglected Predator from previous posts and youtube. In addition to your thoughts on neglected engines in general, feel free to reply about any important considerations about used engines that I missed. Thanks in advance!

By the way, here is a link to my project log thread if you are interested:
http://www.diygokarts.com/vb/showthread.php?t=40027

 

[bob58o]

That Emulsion Tube (first pic) needs some attention for sure. There are more holes than that one down the length of it. It should look something like this....

If it were me... I'd pop the head off, take the valves out, check the piston (and rings) and cylinder, clean thoroughly, re-lap the valves, replace the head gasket,....

 

[Karttekk]

Drain the crankcase, pull the spark plug and put a squirt of oil in the cylinder, pull the starter rope a few times to make sure the piston moves and is lubricated, reinstall the plug, put new oil in it. If you think the carb cleaned up enough to start it, see if it will fire. That should tell you if the engine is worth doing anything to it before a complete disassembly. Those engines are cheap enough to replace, plus you'll have a new engine with a warranty.

Thanks