Mower suddenly will not start. No spark. Replaced spark plug and air filter. Still no spark.
SOURCE: Sears Craftsman mower-Tecumseh engine 3.75 HP-
check the linkage for the governor, maybe on the wrong side,when off it should be pushing the throttle wide open, the governor brings it down after start up!
SOURCE: i changed oil, blade, spark
Hi Make sure the blade and shaft can easily be moved by hand. First, remove the spark plug wire from the plug. Reach under the mower and see if the blade will turn or if something is stuck between the blade and the mower. Also remember that you have to hold the safety bar when you are starting the mower or the engine won't turn. It is possible that the cable from the safety bar to the engine brake has come loose. Follow the cable from the safety bar to the engine and make sure it is working.Also check whether the line from the gas tank to the engine is crimped? Also check this link to troubleshoot your problem:- http://www.ehow.com/how_7363405_troubleshooting-push-mowers.html
Hi
Make sure the blade and shaft can easily be moved by hand. First, remove the spark plug wire from the plug. Reach under the mower and see if the blade will turn or if something is stuck between the blade and the mower. Also remember that you have to hold the safety bar when you are starting the mower or the engine won't turn. It is possible that the cable from the safety bar to the engine brake has come loose. Follow the cable from the safety bar to the engine and make sure it is working.Also check whether the line from the gas tank to the engine is crimped?
Also check this link to troubleshoot your problem:-
http://www.ehow.com/how_7363405_troubleshooting-push-mowers.html
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Mower was working fine for 6 or 7 weeks. Suddenly, when my son was unavailable to mow, I tried to start the mower, but there was nothing to indicate that the engine would turn over when I pulled the starter rope.
I pulled the spark plug, connected the electrical cable and grounded the spark plug thread area against the head of the engine, away from the spark plug hole. I had my son pull the bail lever and pull the starting rope, but there was no spark.
The spark plug and the air filter were dirty. I replaced them with new plug and filter. I repeated the spark test. There was no spark.
Thinking that maybe the grounding switch needed to be advanced just a little more, I used a tool to pull that cable as far as it would go. I did not have extra help at this point, so I had the new spark plug fully installed as if trying to start the engine. There was not indication of the engine making progress on turning over. I still think there was no spark.
Seems to me that either there is a problem with the magneto or coil or the grounding switch. I have a multimeter, but I am not sure how to test the latter. I have a Lawn Boy 10685 with a serial number 2500xx123 (at the moment I cannot remember those two digits, but I believe the first two digits will specify the year).
Any counsel on how to proceed?
I checked some of the site http://www.ehow.com/how_7363405_troubles...
and found how to test the coil. I used the ohmmeter setting of my multimeter and found 3.33 kOhms between the terminal of the coil and the spark plug connection. My understanding is that if it read Open line, zero, or infinity, that the coil was no good. So I believe the coil is good.
A connector that slides over the terminal of the coil has a green wire coming to that connector. So that connector forms a T intersection with this green wire. In one direction the green wire goes into a cable protector that goes into a plastic cover over the rear-while drive area. On the other side of the connector, a green wire goes around the corner of the engine in the other direction and goes up under the fly wheel. I have not yet figured out how to remove the fly wheel to see if that is in order. I will look up some diagrams if I can find them.
That green wire that goes through the rear drive plastic cover ends up at the Module Switch, number 20 in the diagram, and part 108-0967. This switch, it appears to me, senses the presence of a bar of the grass catcher when it is in place. Right? Seems easy enough to test if that is the case.
The module is nothing more than a magnetic switch, in line with the engine ground. Pull the bail back, and open the ground, allowing spark and the engine runs. It sidetracks thru this goofy safety switch.
That magnetic switch senses the iron rod on the bag frame, or mulch plug, and closes the circuit.
Simply jump the 2 wires, completing the circuit. Release the bail, when done, and the engine will still loses spark/ground out. Also, the spring-loaded flywheel brake band will still grab hold and stop, the engine.
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