Coils, Armature with Trigger, Armature Without, What Gives ?

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  #1  
Old 03-17-08, 07:48 PM
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Coils, Armature with Trigger, Armature Without, What Gives ?

I have a B&S 18 HP 422707, type 1214, code 9509155A.

The coil currently on the machine looks to have two pieces. armature and a trigger coil - whiich I understand means that I have a MAGNETRON ignition. A solid, small cable from the trigger coil goes over to a plate on the engine just above the breather.

Question 1 - Is this the cable you want us to disconnect in order to see if the coil is grounding out?
Q2 - Is it that other cable that has the fusable-link looking connector.

From B&S Website I downloaded PDF parts list for my engine - it says I need P?N 394891, which according to the B&S PDF it should include the trigger coil assembly 394791.

When I look for 394891 on the web I find the new part does not have the trigger coil assembly. Here is the odd part, for engine types below 0500, they use an armature that does not have a trigger coil. From images that I have seen, the replacement armature/coil for my engine type, and the one for the engine type below 0500 look identical.

( BOTH ) have spark plug wire leads on the same side of armature and no trigger coil assembly.

Have they done away with trigger coil assemblies?
Does my engine care which replacement armature I order?
Does my engine require an Armature with trigger coil?

I'm pretty sure that the last three questions above are really asking the same thing, but I want to make sure that I understand completely the trigger coil and it's necessity, or lack thereof....

The reason is, on my other mower with 18HP, it had an armature with trigger assy, and I ordered an armature that I was told was the replacement, but it came without trigger coil. ( this is the mower where I installed coil upside down )

Your answer actually impacts two mowers that I have. And the answers will be useful to me in the future to take over the world.
 
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Old 03-17-08, 11:05 PM
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Cool

That small wire you mentioned coming fromt he coil is the one you'll want to unplug to verify if the coil is good or not.

The new coil has the "trigger" or magnetron module. It doesn't look the same because the old magnetron modules were added onto the conventional coils. New coils have the magnetron built in...so it doesn't look the same, but it is. You must have the magnetron or a coil with it built in for it to work.

When you take over the world, remember me and cut me some slack....
 
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Old 03-18-08, 04:13 AM
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Originally Posted by Rain Man av View Post
Here is the odd part, for engine types below 0500, they use an armature that does not have a trigger coil.
Engine type numbers below 0500 had points and condenser which used a conventional coil, The magnatron was built as a add on to take the place of these points and cond. then later built into the coil as cheese explained.


Add me to your cut slack list below cheese.....
 
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Old 03-18-08, 12:28 PM
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Thank you both for the information you provided. I know a lot more today than I did yesterday. Of course, I could have pursued the ole fall back, School of Hard Knocks, but I'm getting tired of taking those tests. I am now ready to start the global task of taking over the world, but first, a brief word from my sponsor, Preparation H.

Oh, alright, I'll cut you guys some slack.
 
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Old 03-18-08, 03:24 PM
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Originally Posted by Rain Man av View Post
I am now ready to start the global task of taking over the world, but first, a brief word from my sponsor, Preparation H.

 
  #6  
Old 03-19-08, 08:08 AM
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I ran across this when I was looking for info related to the flywheel. It's from Briggs and Stratton website and it talks about coils, a brief history about transition from points to transistors, step-by-step instructions on how to test coils/spark plugs, etc, etc, etc. Some of it went over my head. It is titled, IGNITION THEORY AND TESTING

It also debunks some old wives tails - for instance, that rust on the flywheel prevents sparking-which turns out not to be true.

It is excellent reading for somebody who wants to better understand the inner workings of a coil. perhaps I will write Opra and submit it as a short story, the plot rocks.

http://www4.briggsandstratton.com/di...sp?DocID=67479

I hope it is ok to post links to outside stuff.

 

Last edited by Rain Man av; 03-19-08 at 08:17 AM. Reason: cause I'm a moron.
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Old 03-19-08, 02:59 PM
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Originally Posted by Rain Man av View Post
It also debunks some old wives tails - for instance, that rust on the flywheel prevents sparking-which turns out not to be true.

Yeah, It tickles me when someone post to clean rust off the flywheel for spark related issues.....
 
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Old 03-20-08, 02:01 PM
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FYI, the 421700-series engines only had points in early production, not the 422700-series that you have. You did order the 394891, coil, correct?
 
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Old 03-20-08, 04:10 PM
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Originally Posted by puey61 View Post
FYI, the 421700-series engines only had points in early production, not the 422700-series that you have.

You are correct puey, I got my numbers mixed.

It's heck gettin Ole......
 
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Old 03-20-08, 05:33 PM
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Originally Posted by puey61 View Post
You did order the 394891, coil, correct?
Yeppers.

I forgot to run my sponsors ad.

Do you have hemaroids ? Preparation H offers soothing relief.
 

Last edited by Rain Man av; 03-20-08 at 05:58 PM. Reason: For Better Reading
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