# Replacement Engine Wiring



## WayneC (Feb 11, 2005)

I've replaced the BS 16HP motor on my tractor. New motor has electronic ignition module with a "red" wire that needs to be connected somewhere. (There is no spark) I'm guessing it goes to the ignition switch and that I simply have to run a new wire. But before I do that, I just want to check with a knowledgable person. 

Second question, there is a two conductor plug comming from the new engine. Comming out of the tractor from the ignition switch are two cables with the same connector, one a male and one a female. I am not sure which two wires to connect together. I suspect the plug on the new engine is comming from the alternator/generator.

Thanks in advance to keep me from burning up something.


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## bugman (Aug 12, 2004)

oooh usaually i follow the original way the old engine went in and the wiring because well they all are pretty much the same. sorry i just don't know, maybe someone else will but :lol: i follow what the original engine was like and i always come out a champ with it. could check tommorrow on mine though unless someone gives you what you need


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## bbnissan (Nov 7, 2004)

Hmm...what you said doesn't make sense unless B&S has a new ignition system I'm not familiar with. There should be a black wire coming from the ignition module rather than a red wire. Also, the engine should have a good spark even with this wire disconnected (the coil will ground out and produce no spark when you ground this wire). It sort of sounds like B&S may have gone to a safety interlock module sort of like what Kawasaki uses. If this is the case, the red wire will probably need to be grounded for the engine to get a spark.

The two connector harness coming out of the engine is for the alternator. Since nobody seems to use a common color coding of the wiring harness, you will have to do a little work to figure out where the harness needs to plug on the mower. If you follow the wires back, one of the connectors should run back to the ignition switch and the other should run back to the starter solenoid or straight to the battery. The one that runs to the solenoid or battery is the harness that you need to use.


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## WayneC (Feb 11, 2005)

Clarification: This engine replaces a replacement engine that did not use any of those connectors. That engine had a magnito system. This replacement engine is very similar to the original engine. Near the starter, there is a black epoxy module with three wires, two yellows and one red. The two yellow wires appear to go up to the flywheel so after re-thinking this situation, the black module with the "red" wire single connection, may be a diode rectifier which may go back to the run position of the ignition switch to re-charge the battery. Again, I do not know this for sure...only that the engine has a 18Amp alternator. The other connector comming from the new engine has two wires...one comes from the solenoid below the bowl below the carb. The other one goes up to the housing.

Hope this might help clarify my situation. This is my first experience with an engine with no spark and I was only guessing the black epoxy module (about 1.5x1.5 square) was some sort of ignition assembly because of the lack of spark. Any thoughts would be appreciated.


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## bugman (Aug 12, 2004)

ground that wire and see if it gets spark. now all of the briggs engines use magneto's. magnets on the flywheel and a coil system. must be one of those new systems that give spark at low rpm's. 125 rpm's i think


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## bbnissan (Nov 7, 2004)

Ok...you definately have an interlock module on the ignition of the new engine. Since the interlock modules wire differently on different mowers, you need to refer to the wiring directions that are in the owners manual of the new motor.


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## bugman (Aug 12, 2004)

oh man interlock's *crying badly* why!!!!!, man o man i hate those if it is, then crap. *crap* *crap*


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## scrench (Dec 8, 2004)

if you send power to the one that goes to the coil you will fry the coil , . (There is no spark ouch ,,,, module with three wires, thats the regulator , the diod is in the plug coming out of the wires from under the shroud , should be really close to the starter bolt ,, but you will probally have one that will go to the fuel shut off solenoid on the carburator , post your model and code ###"s but if i were you i would not hook up any thing until you know for sure what wire goes where you can cost your self close to a hundred bucks real quick about a split second if you send power to the coil ( "module " ) you might know that but thought i would tell ya ,, does it have a solenoid on the carburator ?


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## scrench (Dec 8, 2004)

post the code ## off the old engine also ????


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## WayneC (Feb 11, 2005)

*Got it working*

THANKS. I used my VOM to check voltages/current before I connected any wires. There were only three possibilities and I chose to connect the 2 conductor plug comming from the carb solenoid and upper hood to a matching jack comming from the ignition switch. Engine fired up and runs like a gem. That still leaves the short red pig tale wire comming out of the epoxy module and I am almost certain now that it has something to do with the charging circuit because (for now) the alternator is charging the battery. (no big deal for now because it starts easy and the battery can be charged manually).

Anyway, motor was on a 42 in Sabre by John Deer tractor, several years old and I put an older "freeby" smaller engine that was bare bones on it for a year or so that did not use any of the original connectors. I recently bought a new (closeout) engine closer to the original, but it came with no manual. The engine on the tractor at this time is a BS Vanguard 15.5HP, 28Q777-0691E1. I looked at a JD tractor today with two different engines and they both had that same epoxy module with the two yellow and one red pig tale. The red pig tale ran back to a connector that looked like it went to the ignition switch. Since I dont think that the store owner would have appreciated me ringing out the wire, I simply left, knowing that at some time I will figgure where to terminate this wire. My best guess is that it goes to the bat terminal on the switch. There is +2.4 volts on this wire when the engine is running. If it were 13 or 14 volts or so, I would know exactly what to do with it, so for now we can close the thread unless someone happens to have a manual and can tell me what that module does and where the red wire goes. Again thanks for the attention.


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## bugman (Aug 12, 2004)

mm all i have to say is good choice on engines. i own a original 12hp briggs I/C on a noma and no rebuilds in around the 8 or 9 years it been here on this earth and it starts easy, uses little to no oil and has very good compression. can't beat it. good luck with yours.


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## scrench (Dec 8, 2004)

module is the regulator , wire is the charge wire goes to the + battery side , or the wire in the harness thats hot all the time , the diod will let juice go one way only out from stator , just find the one in the wiring harness thats hot and tie it in , the one that goes to the anti backfire solonlid on the carburator should only be hot if the key is on and should have no power when the key is off , if its hot all the time it will drain the battery , the way to find the one that goes to the coil to kill it is to hook your test light on the + side of the battery , touch to the wire light should light up , then go off when the key is turned on , that tells ya its grounding

the first 2 digits of the code is the year of the engine on briggs , magnatron came out in 82 ,, but points type still dead shorts to kill ,


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