QuestionQUESTION: Craftsman LT1000 model 917.272061. Tractor runs great, shut if off then it will crank but not restart.(cold or warm) I have swapped the 3 operator presence relays,and seat sensor switch with ones from another tractor and did not make any difference. Eventually it will restart and run fine until trying to restart and same thing. Does not have a pattern at all. Brake switch and blade safety switch seems fine. Engine cranks but no start. Tried starting fluid in case of not getting fuel but still no start. Then for no apparent reason it will start right up and run great until I shut it off and restart. And again it does not matter if the engine is hot or cold or how long its been running or how long its been off. Any ideas??? Kinda at a loss or more ideas at this point.
Thanks
ANSWER: If it will not start on starting fluid then you know the problem is not a fuel issue. This leave ignition and compression.
Have you replaced the spark plug? I've fixed some weird problems like yours with a new plug.
When the engine refuses to start, check for spark. If you have spark the ignition coil and ignition system is working...other than maybe the spark plug. If you do not have spark then you know you have an igintion problem.
If you have spark and fuel but it will not start, then compression would be suspect. Here is the link to your engine's service manual. The manual tells you how to check compression. If you do not have a leakdown tester you can check the valve clearance to be sure the clearance is with specification if you have the adjustable design.
Try a new plug first.
Eric
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QUESTION: Eric, I tried a new plug today and it ran great...until I shut if off a couple of times and eventually it would not start. Gave up went in the house and tried later and again started right up. Could it be the coil?? Can the coil work intermittently? ( engine being hot or cold does not make any difference)Or one of the safety switches working intermittently? I am getting kinda frustrated. Thanks for any advice you can give me.
Chris
AnswerI've had both cause problems similar to yours. Once in a while a coil will have an intemitent problem. An in-line spark tester is very handy to test the ignition system when the mower won't start. As soon as you know the mower won't start hop off, install the ignition tester and check for spark.
I also had a connector on a Lawn Chief rider that would not always provide a good enough connection to allow the mower to start. This took me several weeks to track down because the problem was intermetent.
I use a Briggs and Stratton ignition tester, part number 19368, to check for intermitent ignition problems. Tecumseh part number 670366 is the same thing but usually a few bucks cheaper.
One technique you can use to isolate the ignition system from the main wiring harness is to remove the top engine shroud to access the ignition coil. Follow the small, single wire from the coil to the engine block where it connects to the main harness. Dis-connect the wire, either from the coil or the block connector. However, with the wire dis-connected you will not be able to turn off the engine. You can connect a toggle switch from the engine block or coil and to a ground. To turn off the mower just use the toggle switch. What you are doing is grounding the primary side of the coil which stops current flow thus stopping the spark. This what your ignition switch does when you turn the key off...it grounds or shorts the primary coil voltage to ground...very simple. This tip should help determine if there is a safety switch on the main harness is causing the problem. With the toggle switch in place and an inline ignition tester you should be able to verify if the coil is properly working.
