You can still watch Vice Grip Garage on his Youtube channel. VGG, Puddin's Fab Shop and Mortske Repair (all on youtube) frequently do "first startup in a long time" episodes, I like the way VGG does it a little better because he recommends priming the carb with 2 stroke fuel/oil mix to give some top-end lubrication if it does light off.
The last engine I woke up after a long sleep got a real thorough going-over. Gave the cylinders good amount of Marvel Mystery Oil before even trying to turn it with a wrench. One I confirmed rotation (which pushed most of the Marvel out) I pulled the rocker cover and confirmed all valves opening and closing, then flipped it over (since it was out on a stand) and pulled/cleaned out the pan and oil pump pickup screen. Once it was in the car I spun it with the starter (but no plugs) until I saw oil pressure and confirmed oil at the top of the engine, did compression checks to validate the health of the head gasket, then proceeded to deal with spark/ignition and the carbs. Overkill for most cases but since I was transplanting it from one car to another it wasn't much extra work. Once I got it to light off, then I went ahead and finished out the cooling system so it could run long enough to get a few heat cycles. Only thing I didn't do was pull the head, but since I personally had heard it run 20 years ago I took a leap of faith on the head gasket.
With a engine already in the vehicle I'd go this way:
- Pull plugs and give the cylinder walls some oil before even trying to hand-turn it (may save scratching a cylinder wall).
- Verify rotation with a wrench on the pulley nut (listen for bad noises while turning). If it rotates some then gets stuck, probably wise to pull the rocker cover(s) and make sure you don't have a stuck valve - forcing it could cause damage.
- Disconnect the fuel line coming into the fuel pump (in order to avoid sucking up rust laden, expired, varnished up sludge that had at one time been fuel).
- If it has actual oil (not contaminated, still feels slippery to the touch, not smelling like gas) it should be OK to light off for a minute or so - if it seems bad change it out before spinning it with the starter.
- Spin it with the starter while the plugs are out (going to throw the oil previously added to the cylinders around, use rags if the mess concerns you). Spinning with the plugs out means no compression, minimal pressure on any of the moving parts until oil pressure builds up and gets back into where it is needed. Make sure it builds oil pressure. Again, good time to listen for any suspicious noises. Also this is a good time to do a compression check if you feel it might be helpful - if it seems a bit low no immediate cause for panic, the rings may be a bit stuck and need to loosen back up.
- Repair/replace whatever needs it in the ignition system to get sparks happening. Reinstall the plugs and wires (replace if suspect).
- Prime the carb (2 stroke fuel has a bit of oil in it, but if you oiled up the cylinders before starting its not really critical).
- Make sure the carb and linkages move freely. Having it fire off and immediately go wide open past redline is a good way to kill an engine. The goal is to wake it up gently.
- See if it wants to run. Even sputtering and popping isn't a bad thing, that indicates that its trying.
Once you get it to light off even briefly, you'll know its going to run. I like to get to that point before troubleshooting cooling system, fuel delivery, cabin electrical, etc. No point it doing all of that before seeing if it runs, and then having to pull the engine because it is dead.
