how to check elect ignition on 2 cyl Briggs

screaminghollow · Feb 17, 2015

step son went to trn the engine off and it kept running so he jammed a screw driver into the blades behind the ignition switch to "short it out. It is a circa 1980 opposed twin horizontal shaft magnetron engine. needless to say I have no spark now. Can't find model number. How do I check the electronic ignition module to see if he fried it? (small black plastic box with red wire going in and two thin black wires coming out.)

Bob · Feb 17, 2015

I think what you are calling "small black plastic box with red wire going in and two thin black wires coming out" is the voltage regulator for the alternator charging system.

What MAY have happened is that he fed battery voltage back into the coil/magnetron/armature that makes it's own power and NEVER gets 12 Volts and fried it.

That unit is cleverly hidden under the air shroud covering the flywheel.

FIRST, try checking for spark with the "kill" wire from the magnetron disconnected from the ignition switch.

<img src = "http://gardentractorpullingtips.com/images/bs-coil.gif">

This should be the complete Magnetron ignition system.

screaminghollow · Feb 17, 2015

Thanks. now I am really confused. The ignition switch has three tabs in the back. One for a back ground wire that is connected at the other end to a small screw at the top of the engine block at the carburetor. Another tab with a medium red wire that goes to the solenoid switch and the third had both the heavy battery wire and the thin red wire that goes to the plastic box . Is that black ground wire the kill wire? Is that the one that should not get battery charge? There are two black wires from the plastic box that appear to go under the engine shroud

screaminghollow · Feb 17, 2015

Ah I found a picture of a voltage regulator in a catalog, that is a voltage regulator. So maybe the coil is fried. great. he probably crossed that batter0y/charge tab with the kill wire. I will check for spark with the kill wire disconnected in the am.

Thankyou so much.

I am still puzzled about how the kill wire worked electric wiring seems like a devious plan to drive folks crazy

T.R.K. · Feb 17, 2015

The kill wire from the coil is connected to a ground wire through the ignition switch when the ignition switch is turned to the 'off' position. In all the other positions of the switch it is not grounded.

The switch or wiring may have been failing when it refused to stop. No ground through the switch for some reason.

If he ever experiences this problem again, he can stop the engine by using something insulated to pull the spark plug wire(s) off the spark plugs.

joe csuti · Feb 18, 2015

If you can't find an id tag on eng,after you remove flywheel cover clean off same & check all sides of same under a bright lite for mod,type & code numbers which may be stamped into cover as you may need these numbers to get a new coil as early mod magnetron ign on opposed twin eng had an ext trigger module mounted on coil that was replaceable seperate from coil(this may be what's cooked)later versions trigger was enclosed in coil and coil/trigger were replaced as a unit.

If you do find mod/type# on eng & unless you are 100% sure ign a magnetron(pointless) system or same marked on eng with a decal check type# of eng
if below 0500 the early opposed twins below 0500 had point type ign system & the coils are NOT interchangeable,if ign a point type magneto system it may be necessary to remove carb or intake manifold/carb to get to points as points may be burnt/welded together.

ShadetreeRet · Feb 18, 2015

"electric wiring seems lie a devious plan to drive folks crazy". You got that right!!! LOL

ShadetreeRet · Feb 18, 2015

Sounds like you may need a new ignition switch also.

how to check elect ignition on 2 cyl Briggs

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