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engine swap

sleepy2008's Avatar

Join Date: Jan 2009
Posts: 5

09-14-09, 09:24 PM   #1  
engine swap

Had B&S 11.5 on older MTD tractor until it blew--put on 12.5 Tecumseh on and can't figure out wiring to make it run right. Will start but with wiring and lights hooked up it stalls or if runnung then touch wires it shuts off. Both motors have 4wires yellow red green any help can't find any imformation online to help

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cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,567

09-15-09, 07:39 PM   #2  
Tecumsehs usually have a green wire for the kill switch, so that would go where the briggs probably had a single black wire.

One wire from the mower has 12 volts on it with the key on. This one goes to the engine wire that has 12 volts or better on it when the engine is running full speed (got a test light or voltmeter?).

You said you have 4 wires, one red, green, and yellow. That's 3. The yellow is probably the lights and if the briggs had a dual alternator and the tecumseh doesn't then you may not be able to connect it to it.

"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!


Join Date: Mar 2007
Posts: 354

09-16-09, 07:25 PM   #3  
If I had the engine numbers off the Tecumshe engine, I probably could tell you what each wire is. Usually the Green is used to shut off the engine, The red is usually 12 volts out put and the yellow is for ac headlights. On some of the engines there is a green wire on the carb shutoff valve, So it helps to know the numbers.

sleepy2008's Avatar

Join Date: Jan 2009
Posts: 5

09-21-09, 03:02 PM   #4  
hey camino kid--there are only 3wires yellow green red.numbers on motor are
SPEC 206915E
DOM 03192C80047
tractor wires are
Red(from motor) goes to red to L on ignition switch
Yellow (from motor) goes to G on ignition switch
Green (from motor) goes ????? if plugged to lights like before it won't start just turns over. Leave it unhooked and it runs but won't shut off until I touch the green to headlight wire.
Tried switching around Yellow and Red but makes funny noise and acts funny
does this sound right

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