# Briggs 19 HP Wiring question



## Viper32

Okay I am putting a Briggs 19 HP 42a707 1251 01 engine on a newer but motor expire Ryobi Riding Mower. The rider originally came with a 19HP Kohler. My question is the Briggs has three wires going to the engine and Kohler had I think 4. I need to know what the wires are on the Briggs and how to figure out which to coneect the the mower. Any help would be appreciated.

Mark


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## big ed

Switching Engines Is One Thing But Switching Manufactures Means Tracing All The Wires And Seeing What Gets Voltage And In What Position Or The Next Engine At The Turn Of A Key May Burn Its Electrical System Or Just Blow Fuses Due To Shorted Connections Get A Wiring Diagram And Start Looking Where The Old Stops And The New Begins Good Luck


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## 30yearTech

What is the model number of your Ryobi Riding mower? 

The wires comming out of the Briggs engine are probably an engine ignition kill wire, a dc charging circuit, and an ac power circuit. 

Most Kohler engines have a voltage regulator mounted on the engine and only have 2 wires going to the wiring harness, but this may not be the case for your application. As big ed described you have to be careful, if you hook up the kill lead to a power source you can fry your ignition module. Best to look at a wiring diagram of your old setup to see how to wire your new engine.


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## Viper32

I will get the model numbers off the donor mower that motor came off of and the new mower tomorrow. Will that be enough info to help with this problem?

Mark


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## 30yearTech

Yes it should be. Just let me know which mower the engine came off of and which one it's going on.


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## Viper32

Okay the motor came off a Craftsman Model 91725260 Lawn tractor. It is going on a Ryobi HDK19H42 Mower. I can pull up the parts diagram fro the Ryobi but cannot find the Craftsman one. Heres the Ryobi one http://www.oscar-wilson.com/MANUALS/AYP/96016000402.PDF

Mark


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## 30yearTech

Well looking at the wiring diagram for your Ryobi, I only see 2 wires that would have hooked up to the engine from the wiring harness. One to the ignition kill switch, and one for the charging circuit.

I will try to locate a diagram for the sears unit and see what it had. Most likely you will only need to hood up the charging circuit and the ignition kill, the a/c is usually used to power the lights on alot of mowers, this circuit will probably not be used, but I will check and let you know what I find out.


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## bugman

do you have the wiring from the frame the replacement came from? Swap the wiring, it isn't too hard.


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## Viper32

bugman said:


> do you have the wiring from the frame the replacement came from? Swap the wiring, it isn't too hard.


No I do not have the wiring from the donor mower.

Mark


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## 30yearTech

Viper32, the model number for the donor mower shows a horizontal shaft engine and the Ryobi shows a vertical shaft engine and the model number for the engine you are using off of the donor mower shows that it is an opposed twin cylinder.

On the Briggs engine, from the front left side of the engine (facing the carburetor) there should be a single spade terminal with a wire plugged into it. This is the ignition kill wire, this needs to be hooked up to the wire comming off of your "M" terminal on the ignition switch (should be a black wire).

Then comming off of your Briggs engine (depending on which alternator you have) you probably have two wire coming out into a plug, if this is correct one wire going to the plug will have a diode attached to it and covered with shrink wrap. This is the DC side and should be attached to the starter solenoid (same side as cable going to battery). You do not need to connect anything to the other lead coming from the engine, this is non regulated AC current and can only be used for lights or other items that do not need DC current. 

If you have a multimeter double check the output when the engine is running before hooking up these electrical connections, if you hook up the AC side to your battery it will burn out the charging coil.

If the 2 wires with a plug go to a little box that has one wire comming out of it, this is a bridge rectifier (voltage regulator) it will have one wire with a round connector coming out of it, this would be DC current and would need to be hooked up to the starter solenoid as describe above.

Oh yeah and the other cable coming from the starter solenoid will go to the starter on the engine. (I forgot to count that as a connection in my earlier post) So that makes a total of 3 conections to your old and new engine.

Hope this helps, if you have any questions feel free to email me.

Ken


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## Viper32

I am sorry the correct model number for the donor mower is 917.252560 maybe that will clear it up. The donor mower had a 19hp briggs twin on it.m The briggs motor has a plug that three wires go into that are black, orange, and red. The Ryobi body has 4 wires coming out that went to the motor of the kohler that are Blue, orange, white, and black/white striped. Maybe this will help some more on telling me which ones to hook to were. I already have the red wires for the starter and solenoid hooked up and have ran the engine.

Mark


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