Small Engines (Lawn Mowers, etc.): honda gc160 exhaust valve stuck, air filter assembly, briggs and stratton

Question
Dear Ben;
I am new to small engine repair. I have a gc160 honda EMYB 1624006 from a Billy Goat quiet blow that is not starting. It had the wrong spark plug installed and it backfires through the air filter assembly. I took the valve cover and the exhaust rocker was cracked and the valve stuck. I pushed it down and now it moves up and down free. What makes this to happen ? Is this a interference engine and the time belt is off or is this a common problem with hondas ? Other than replacing the rocker is that anything else I need to do ?
Thank you for your answer, have a good day.

Answer
Joe

This is probably the most common problem you are likely to encounter. The cause is very often the same - lack of maintenance.
Note that the assumption here is that it cranks - the crankshaft and blade rotates in a normal manner but the engine never catches. Some larger (Briggs and Stratton) engines may have a low-oil cutoff switch which will stop the engine if the oil level is inadequate. However, this is not likely on a push mower.


In the case of a recoil starter, you are able to pull on the cord and the crankshaft with the blade rotates and it feels normal but the engine does not start. If it feels like nothing is engaging, then the starter mechanism or clutch may be broken. Of course, if the cord breaks, then the problem is obvious!  

In the case of an electric starter, the engine cranks but never catches. If there is no response to the button or key, then the outlet may not be live, the battery may be weak or dead, or there could be a bad connection or bad starter motor. If the motor spins but doesn't engage the engine, the overrunning clutch or gear could be broken.
If you are unable to pull the cord (or the auxiliary starter on one with electric start), there may be a clump of grass stuck between the blade and the deck or there could be serious internal damage, especially if you just encountered an immovable object. See the section: Lawn mower will not start after the blade hit an obstruction. However, you didn't forget to engage the dead-man bar, did you? On most inexpensive mowers this safety interlock is needed to both enable the ignition system and release the blade brake.