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zchornyak · May 20, 2008, 04:36 AM

I've disabeled all the safety switches, the engine turns over fine and I've isolated the ignition armateur (unplugged the ground wire from it.) the old one had spark on one lead but not the other so I figured it was bad. It ran sometimes but other times it would not start. Now that I bought a new ignition armateur I can't get any spark at all. What gives?

Thanks in advance for any advice..

MOWERMAN2468 · May 20, 2008, 06:31 PM

You could have possibly installed the armature upside down, look on the coil and it will say either: cyl side, or top, or something to that nature to let you know which way to install. This is a common mistake, and a costly one, seeings as how I do not know of anyone that will allow the return of electrical parts.

zchornyak · May 22, 2008, 03:02 AM

Originally Posted by MOWERMAN2468

you could have possibly installed the armature upside down, look on the coil and it will say either: cyl side, or top, or something to that nature to let you know which way to install. This is a common mistake, and a costly one, seeings as how I do not know of anyone that will allow the return of electrical parts.

How would installing it upside down be a costly one. Not sure how that would bust a coil?

MOWERMAN2468 · May 22, 2008, 06:35 PM

Well, zchornyak, installing a coil upside down can ruin it immediately, therefore you would have to purchase another coil, which would be costly. You can improvise the gap between the coil and the MAGNETS of the flywheel using a standard business card as a gauge in a pinch.

Thorb · May 5, 2010, 09:19 PM

Hey... guys... I got the same engin on a Roper...
It lost spark... then got it back then lost it again...
Is there a reading [in ohms] on the magneto coil I should know... to test it?
No spark on either wire.

wildbill1947 · Oct 21, 2011, 01:04 PM

I have a 1995 B&S 'L' head, twin cylinder, 20 hp. I have a new Magnetron coil installed correctly, gap at .011", ground wire removed... and NO spark. The motor oil is cold and thick, so I am not getting a high rev while cranking. What are the correct ohm readings and where to take them to determine if B&S sent me a defective coil? Please reply to: [email protected] thanks

DG · Oct 21, 2011, 03:11 PM

Unhook the ground wire going to the coil then see if it starts

wildbill1947 · Oct 24, 2011, 09:12 AM

Most of the later coils, like the B&S Magnetron, must have about 300 to 350 rpm before the unit will create a spark. I am currently working on a 1995, 20 hp, B&S. I just installed a new coil and neither plug wire would not spark due to the low cranking rpm with the old battery. I had to install a new battery and it had the power needed to spin the motor fast enough to make the coil work. Also, make sure the air gap between the coil 'legs' and the flywheel magnet is set .010" to .012". If you have removed the "kill" wire from the coil, and if the coil is good, and if the air gap is correct, and if you spin it at least 300 rpm, it has no choice but to create a spark.

DG · Oct 24, 2011, 03:04 PM

Are you answering your own?
Don't know of any Ohms test , I always just check for spark ,
Did you put the coil on with the right side up.This would cause no spark.
Luck

samuelg127 · Apr 26, 2012, 08:45 AM

Hope your still out there, I unhook the ground wire going to the coil and got good spark so what is wrong with it decause I get no spark when I plug it in any idals of what is causing this thanks sam

DG · Apr 27, 2012, 07:00 AM

Check the wire you unplugged and see if it has a bad place , also look for a inline diode .
Luck