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garyb

Coil problem on my 5212.5

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garyb

I recently swapped out my 12.5hp motor with the 16hp from another Simplicity mower, and put a new ignition switch in (correct part #) I’m on my 3rd coil now.  Why am I going through coils? I’ll get about 10 minuets or so of run time and then no spark the coil is ruined 

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fishnwiz

Double check to be sure your plugs are correct for your mower....also bad plug/coil wires may be at fault if old and worn.

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SimpleOrange

Most coils today have a built in ballast resistor, it's possible the coils your installing do not have an internal resistor.

If a non ballast coil is operating on the full 12 volts after the engine starts the primary winding will burn out in short order.

Usually as the coil overheats the engine will misfire.

 

 

ignition-coil-ballast-resistor-wiring-diagram-lovely-1988-420sel-mercedes-benz-parts-diagram-e280a2-sipra-of-ignition-coil-ballast-resistor-wiring-diagram-657x657.jpg

Edited by SimpleOrange
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garyb

There’s it kinda sounds like the issue it will sputter and die in about 3-4 seconds time,  what is a good coil to use? I’ve been getting the ones recommended for that size motor but they are only about $15-$18 

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SimpleOrange

Also make sure you have the power lead on the correct side of the coil, next time you purchase a new coil ask if it has an internal resistor or if it requires and external.

Most coils are marked with a plus and minus sign while others are clearly marked Batt for the power lead.

I'm safe to say that any 12 volt automotive coil used on a breaker point ignition system, its possible that a coil  from an early electronic ignition system would also work.

On your next coil purchase ask the couterman if it has an internal resistor, if so claim warranty on your previous purchases.

Old school resistor shown on the image below, to save a dollar the automotive manufactures whet to a resistor ignition wire that looks just like ordinary sheilded wire.

Using the external resistor follow the wiring diagram in previous post, you;ll notice that one power lead comes off of the starter solenoid. The sol lead feeds a full 12 volts to the coil to give it an extra jolt for cold weather starting.

Then once the engine is running the power to the coil comes off of the ignition switch through the resistor where the voltage is reduced to around 9 volts for continuous coil operation.

 

 

bal.png

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TommyK1

FWIW, I lost the acorn key for my 5212.5.  The only thing they had at Farm and Fleet, was 2 keys with an ignition switch.  I was desperate and needed to replace my IGN switch, so I bought it... 5 terminal IGN switch.  (the IGN switch is another story)   During my investigations I found that there are two styles of 5 terminal ignition switch.  BOTH have the same terminal lay-out pattern, but the spade connectors are wired different.  The 5 terminal wiring harness will plug into either switch, but with the wrong switch, bad things could happen.  If you still have the OEM switch, compare the letters stamped into the side of the spade terminals to make sure you have the correct switch.  One source (B/S switch installation instructions, I think) indicates that one style is a metal switch and the other plastic.  They are not wired the same.  The wire harness plug has to be re-wired to use the replacement switch.

 

Edited by TommyK1

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