Engine Won't Start


Old 03-05-03, 02:43 PM
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Engine Won't Start

I own a MTD 18HP Briggs and Straton riding lawn mower.This engine has no points or electronic ignition. The battery is good it turns the engine over real fast but I have no fire. How do I check the magneto and the coil to see if they are good or not??? Do you guys have any ideas and am I missing something that needs to be checked? Thanx for your help Bubba
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Old 03-05-03, 02:59 PM
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Hello BUBBA 1, first, lets check the neutral safety switches. One will be under the seat and one on the clutch. Also, the blade engage will have one and any one of them could be the culprit. Most of the time this is where dead shorts will be found. These plugs can be unplugged one at a time and perhaps you will come across one that when unplugged will let the engine fire.....Mike
Old 03-05-03, 03:50 PM
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Thanks Mike but all the safety switches are ok. I just need to know how to check the maneto and the coil. Any other suggestions will be a great help. Bubba
Old 03-05-03, 05:59 PM
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Magneto AND the coil?
The ignition module/coil/etc. is the box with the plug wires
coming out of it. The large finned wheel with the magnets
is the flywheel. There is a small wire plugged into the base of the
"coil", that is the kill wire, and if unplugged, will allow the "coil"
to fire everytime the flywheel is rotated. If the coil does not fire
then the coil is bad, or less likely, the flywheel. But to make sure,
unbolt the coil and sand and clean all of the mounting points of
the coil first and reinstall, after gapping the clearance with a
business card.
If you find the coil bad, then be aware that the greatest killer of
coils is a supply of voltage to the "kill" wire circuit, and voltage to the ignition is lethal, so look for possible sources of voltage
like melted together wires, or an incorrect keyswitch.
Old 03-05-03, 07:08 PM
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Also, if anyone replaced that keyswitch with one from the autoparts store, mostlikely its the wrong one and they have already popped the ignition coil
Old 03-06-03, 12:33 AM
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I have seen that before! (wrong switch) many times.

I agree with Fish...unplug the kill wire and see if you have spark.
Old 03-06-03, 05:51 AM
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engine won't start

Thanks all for your replies this gives me something else to go on.Will work on it just as soon as my fingers thaw out. Bubba

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