Hi,
I have a strange problem with the GCV160A Honda engine on my Troy-Bilt 21-inch Push Lawn Mower (model: 11A-542Q711).
The engine started the first time (as always) and ran perfectly (as always) until the bag was full, so I stopped the engine, emptied the bag and went to start it again (w/o choking since the engine was hot), but it did not start.
So, I tried a few more times that day, but nothing.
I then tried a few days later but again, the engine wouldn't start.
Although this seemed like an electrical problem (since I never heard any sign of ignition / combustion like I usually do) I pulled the air filter and verified that the butterfly / throttle valve was moving freely. It was.
I then sprayed some carb cleaner directly into the carburetor in case there was a blockage in the gas line (which I was fairly sure was not the case because I could clearly smell gas after priming). I tried starting it again, but still no luck.
So I then removed the starter recoil assembly and the plastic cover to get at the ignition coil / magneto. I disconnected the spark plug wire, clamped the safety bar (dead man's handle), inserted a copper wire into the spark plug wire connector and positioned it about a millimeter off of the cast aluminum engine casing. I then rapidly rotated the flywheel back-and-forth such that the two magnets embedded in the flywheel would move past the two ends of the U-shaped magneto core to see if I could see a spark. I did this in the dark so that it would be easier to see, but never saw a spark.
Since the mower was apart I also tested the continuity between the little connector that goes to the kill switch and ground. When the dead man's handle was not depressed, there was continuity, and when you depress the handle, continuity is lost. I was glad that I saw a change because I didn't want to have to pull the flywheel to get at the switch.
I also verified that both magnets embedded in the flywheel were good (they both were able to firmly hold onto a steel socket).
So at this point I assumed the problem was a bad magneto and ordered a new one.
Well, I just installed the new magneto, reassembled everything and tried starting it again, but still nothing! It's a mystery as to why I'm still not getting a spark.
So let me ask the following question: Why does the dead man's handle *open* the circuit when depressed? Given that the little electrical tab on the magneto already shows continuity to ground (the engine case), what is the kill switch actually doing? To me it makes more sense if the kill switch would either: 1) keep the circuit open until the handle was depressed or 2) remove a (parallel) shunt across the coil when the handle is depressed.
I guess what I'm asking is: What is the high-voltage electrical circuit? One end of the magneto coil is clearly connected to the spark plug such that high voltage induced in the coil will jump the spark plug gap, return to ground, and then complete the circuit through the kill switch and back to the coil. Is that true?
Thanks,
John
I have a strange problem with the GCV160A Honda engine on my Troy-Bilt 21-inch Push Lawn Mower (model: 11A-542Q711).
The engine started the first time (as always) and ran perfectly (as always) until the bag was full, so I stopped the engine, emptied the bag and went to start it again (w/o choking since the engine was hot), but it did not start.
So, I tried a few more times that day, but nothing.
I then tried a few days later but again, the engine wouldn't start.
Although this seemed like an electrical problem (since I never heard any sign of ignition / combustion like I usually do) I pulled the air filter and verified that the butterfly / throttle valve was moving freely. It was.
I then sprayed some carb cleaner directly into the carburetor in case there was a blockage in the gas line (which I was fairly sure was not the case because I could clearly smell gas after priming). I tried starting it again, but still no luck.
So I then removed the starter recoil assembly and the plastic cover to get at the ignition coil / magneto. I disconnected the spark plug wire, clamped the safety bar (dead man's handle), inserted a copper wire into the spark plug wire connector and positioned it about a millimeter off of the cast aluminum engine casing. I then rapidly rotated the flywheel back-and-forth such that the two magnets embedded in the flywheel would move past the two ends of the U-shaped magneto core to see if I could see a spark. I did this in the dark so that it would be easier to see, but never saw a spark.
Since the mower was apart I also tested the continuity between the little connector that goes to the kill switch and ground. When the dead man's handle was not depressed, there was continuity, and when you depress the handle, continuity is lost. I was glad that I saw a change because I didn't want to have to pull the flywheel to get at the switch.
I also verified that both magnets embedded in the flywheel were good (they both were able to firmly hold onto a steel socket).
So at this point I assumed the problem was a bad magneto and ordered a new one.
Well, I just installed the new magneto, reassembled everything and tried starting it again, but still nothing! It's a mystery as to why I'm still not getting a spark.
So let me ask the following question: Why does the dead man's handle *open* the circuit when depressed? Given that the little electrical tab on the magneto already shows continuity to ground (the engine case), what is the kill switch actually doing? To me it makes more sense if the kill switch would either: 1) keep the circuit open until the handle was depressed or 2) remove a (parallel) shunt across the coil when the handle is depressed.
I guess what I'm asking is: What is the high-voltage electrical circuit? One end of the magneto coil is clearly connected to the spark plug such that high voltage induced in the coil will jump the spark plug gap, return to ground, and then complete the circuit through the kill switch and back to the coil. Is that true?
Thanks,
John
