Small Engines (Lawn Mowers, etc.): Honda GX120 Spark Plug and Magneto, honda gx120, walk behind aerator

Question
Hi there. I recently purchased a Honda GX120 engine on a bluebird 530A walk-behind aerator, and it worked great until I went to change the oil. The unit is only a year old, and had been working perfectly at purchase.

When I changed the oil, the machine started on the first pull, but when I adjusted the throttle to warm it up a little faster, it started pouring white smoke out of the exhaust and shut down. The recoil rope portion locked and the engine would not restart. I know now that the white smoke was the burning of the new oil caused by my not giving the engine time to warm up properly.

Anyway, I ended up removing the engine from the assembly and took it apart about halfway: I had the valves exposed, but not the cylinders, and the exhaust was off, as well as the fuel line. I drained all the fuel and oil and then re-adjusted the starter rope assembly, with the spark plug right over the magneto.

When I put everything back together and filled it back up with oil and fuel, the engine wouldn't restart. I am assuming that I may have put the spark plug magnets too far away from the magneto on the rope, as the spark plug should be working fine.

My question is: How far should the spark plug magnets be from the magneto on the recoil assembly in order to get the greatest electricity from the magnetic field? If I have to disassemble it again, I want to make sure I get it right this time.

Thanks!

Answer
Place a business card between the magneto and the flywheel magnets.  This will be "just about" right.  Not perfect...but will work fine.  If you still don't have spark, check and see if you have a LOW OIL shutdown switch.  Make sure the engine is FULL of oil.  IF the engine is low on oil it will not start either.

If you DO have a low oil shut down switch AND the engine is filled with oil, but still wont start temporarily unplug the wire coming out from the inside of the engine and see if it starts.  If it starts at this point you have a defective oil switch.  

If you need further advice please feel free to ask.

Happy Wrenching!

Dave