Briggs & Stratton lawn mower with no spark.

Joe Soy

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Greetings Lawn World,
I do refer to mower as being "old", it is 20 years old and to me seems old for a mower but what do I know, jus' sayin'. I bumped the air gap to .015" but no luck. There have been some comments about testing for spark correctly, could I have been doing it incorrectly? I have the plug connected and I ground it on a freshly cleaned (1000 grit emery) part of the engine and trun the fly, with the kill wire connected and disconnected. I held it in my hand just as a last resort and felt a mild, very mild, jolt from time to time, not consistant-and not a good way to test-You'll only make that mistake once. As for points and condenser, I looked under the fly wheel and see nothing, also there were no such parts listed in the exploded diagrams I've seen. I haven't taken the fly wheel off though. I've had a lot of cars in the past with points etc. but the ignition system on this thing seems dead simple, if there were points and a condenser they would have to be in line somewhere. I'm leaning toward the original idea that B&S may have sent me a defective part. There have been some good ideas here and I am greatful for the help.
 

Fish

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No, these ignitions are pretty much straightforward. If you spin the flywheel with a coil bolted on, and get no spark, and the kill
wire disconnected, then the coil is bad. Well the flywheel may have lost it's magnetism, but I have never seen it.

So if you have correctly checked the spark, as stated above, then the coil/coils are bad.
 

Rivets

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To me that does not look like a Briggs coil? Can you post the part number for that coil? It should be #802574
 

Joe Soy

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Fish and Rivets,
Thanks I was getting a little worried there. The part number I have from Briggs and Strattons confirmation email is: 590454 -ARMATURE-MAGNETO. Which, obviously does not match the one posted by Rivets. I don't remember the part number from when I ordered it but I used the B&S web site and the model and type number (see first post) that was stamped on the metal cowling of the mower to order the part. It sure looks like my original coil, which is why I thought I had a good match. The original has a factory stamp 9508P which was useless in searching. I'm going to have to search part #802574 and see what turns out. Thanks folks, could be on to something...
PS. Like the Gonzo icon by the way, I'm a big HST fan.
 

Rivets

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There were two coils that could be used on your engine. #802574 or #793353 if you have a screw on spark plug boot.
 

EngineMan

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To me that does not look like a Briggs coil? Can you post the part number for that coil? It should be #802574


Interesting one this.......!
 

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Joe Soy

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Hello again,
Lord, how did I screw that up? I have my notes from from my search of the B&S web site and they gave me the choice of #793353 or #590454...this is why I don't like ordering on line.
Anyhow, I'm getting part# 802574 and I'll post back when it arrives. Thanks for all the help with this puzzel.
 
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