Initial post-overhaul testing
Assuming you didn't make any mistakes, the engine should start on the first pull. As you start it, look and listen for any abnormalities and immediately stop it if any are detected:
- Engine overspeeds due to screwed up governor or linkage.
- Unusual knocking or banging due to parts hitting one another.
- Excessive black, white, or blue smoke from exhaust (or 3 foot flames, I suppose).
- Overheating.
- Leakage of oil or gas.
Assuming nothing appears wrong, run it for a while at slow speed (if you have the option). Continue to be on the lookout for anything unusual. After a few minutes, stop it.
Let is sit for 10 minutes or so and then check, and if necessary, top off the oil.
Now, restart and run it at high. Mow a few lawns.
Congratulations! Hopefully, your engine will now serve you for many more years - or until the blade hits the next curb!