Converted L Head to CDI - How to install the kill switch

chieffan

Tractorologist
Senior Member
Member
Armature is installed and have fire at both plugs. That ground wire from the armature is required to make the system work. As I understand it any open in that wire will kill the engine. A normal key switch does the opposite, off position it grounds the armature, so will have to put a separate ON/OFF switch in that ground wire to kill the engine. This in on an old B&S 16hp horizontal twin L Head engine. Am I missing something or is this the route to go?
 

MiCarl

Tractorologist
Senior Member
Member
My experience is with motorcycles but I'd think the systems would be similar. On motorcycles the Armature is always grounded. There is another wire on the CDI that is grounded to shut down the spark.
 

olcowhand

Daniel In KY
Staff member
Administrator
Never heard of such system for mower engines so not familiar. But sounds like the separate switch to kill is only way to go unless you add a relay that will disconnect the ground when you turn key off.
 

chieffan

Tractorologist
Senior Member
Member
2 plug wires and the ground wire is all that is on these. Never thought of a realy set up. That would work with original ignition switch. Atom makes, or at least did, for different applications. Green (#205) is the most popular for all B&S single cylinder engines. Brown (#209)if you can find it is for B&S twins. White (#5) is for B&S go cart engines. I have 2 or three of the Green in use and they work good, but not for the old twin L head engines. Thanks for that relay suggestion.
 

chieffan

Tractorologist
Senior Member
Member
That did not work out so well. IN the on or off position the engine keeps running. Better check the switch to make sure it is good.
 

chieffan

Tractorologist
Senior Member
Member
Much bigger issue showed up. Blowing oil out the #1 breather hose. Tore it down and found an issue with scoring on the cylinder walls.
Checking on getting it bored 10 over now. Piston with rings are located for +0.010 and +0.020. Will probably go that route from what I have read they will run a long time with the chromed piston and rings from B&S. Won't go after market for sure.
 
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