QuestionQUESTION: The engine will not fire, but will spin when the starter is engaged. I have replaced spark plug, twice, cleaned the carb, but only superficially, I took it off and blew it and used cleaner, but did not do a complete breakdown... I tried holding the plug wire out to see if it sparked but the cap is so long it may have been too far from the plug... The motor is on a 2004 Craftsman 4000 DYT and has over 300 hours...
Thanks in advance for any guidance...
ANSWER: Did you remove the spark plug, re-connect the spark plug wire and ground the spark plug while cranking the engine to check for spark?
I'm betting you have a safety switch preventing spark. Can you send me the Craftman model number, located on the Sears sticker, about the size of a business card? The sticker is usually found under the rear seat or fenders and the model number format will be similar to xxx.xxxxxxx.
Send me the model numbe and I can look up the schematic if it is available.
Eric
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QUESTION: ok, you are hard to recapture, the model number is 917.273635
Now let me tell you what I have done since the last post..
I checked to make sure key was okay and it was or at least it was in place the slots lined up...finally I bought another magneto...
It fired and ran for 5 minutes and now it is doing the same thing.
So am back where I started...
btw, did check for spark and it has none..
again, thanks in advance
ANSWER: Do you have a multimeter? On the ignition model there is a small wire connected the coil, usually a spade terminal. Dis-conntect the wire and see if there is power on the wire, with the key off and the key in the run and start position. There should NOT be any power, ever, on this wire. This wire should be a short to ground with the key off, this shorts the primary ignition module coil to ground and shuts off the engine.
With the key in the run position the wire should be open with respect to chasis ground.
Again, there should be NO power on this wire. With the wire dis-connected you should have spark. If there is no spark then the module is defective. Those modules are pretty reliable and rarely fail, especially two in a row? I have found faulty key switches send power to the module and cause them to fail.
Let me know what you find.
Eric
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QUESTION: I do not have a good multimeter, just a test light (no good if voltage is low, I am sure) and an antique Radio Shack with a needle and it moves everytime you breathe so I wasnt confident in that....
So I went ahead and put on my 3rd magneto, this time left the wire off and the lawnmower runs fine, but sometimes cuts off okay when the switch is off and sometimes doesnt (?)...I plan on getting a good multimeter (any suggestions) and make the tests you suggested. I will have plenty of time this fall to go carefully over anything that may be a problem..Any other way to test key switch or check for errant voltage??? The only other thing I did while I was fooling around was recheck and reset the valves, but starting hadnt been a problem...one other thing, the first module I got was not a B+S brand, should have kept the pkging but I didnt, the current one is...anyway anymore insight you can offer will be appreciated..I dont think I am going to every be comfortable with hooking the module back to the ground, no matter how much I check or find..
AnswerYou don't need to invest in an expensive multimeter. While I have several high-end meters I typically use the $2.99 digital meter I got from Harbor Freight...I don't have to worry if I drop or break it. The meter is good enough to work on mower electrical systems.
It's possible you got a bad coil but I would still check the key switch and the shut-off wire at the coil to see if any power (12 vDC) in on the wire. There is no easier way to check the key switch. If in doubt, key switches are pretty cheap so you could just replace it instead of checking the switch.
Eric
