Briggs key position issue

[frankydp]

New to posting but frequent reader.

I have an issue that I need some test suggestions for.

Briggs Stratton 282707 12HP in an older weedeater rider.

Picked up a mower from a friend that was upgrading. Normal maintenance plus new battery, solenoid, and starter(rusted out base and stripped teeth on top). Also got a new key switch that is a 5 pole as the key was broken off in the old one.

It appears the seat safety is has been taken out of the loop by simple connecting the two wires.

The cutting deck engagement safety sensor was disconnected when I got it. If connected will always kill the engine on cutting deck engagement. Deck works as expected if the wiring harness to cutting deck safety switch is disconnected.

Engine will start without issue if the solenoid is jumped, but only if the key is in the OFF position. If the engine is running and I turn the key to the ON position the engine will die.


Could anyone suggest some testing for me to work through, in order to isolate the issue. I am at a loss on where to start.

Also, does the cutting deck safety switch do more than I think it does?

Thanks for any guidance.

 

[KennyV]

WELCOME to these Forums...
Lets begin at the new key switch... There are TWO types of switches that have 5 connectors...
The first type applies 12 volts to the "Run" terminal when in the On position, and is Open in the Off position.
The second type is Open (nothing applied), to the "Run" terminal in the On position BUT applies Ground to that terminal in the Off position.
On the first type you are applying 12 volts to a coil for ignition and removing it to shut down.
In the second type you Have a magneto and you apply Ground to the kill wire to shut down and Remove that ground to start.

The switches look the same & plug in the same But they are NOT interchangeable....
I suspect you need the Second type but have the First type installed....
& if that's correct,you can easily destroy your magneto by applying 12 volts to it with the wrong switch... :smile:KennyV

 

[EngineMan]

This is has far has I'am willing to go with this, apart from saying you should fit all safety switches back on.

 

[frankydp]

Kenny,

Thanks for the detailed response.

I did order and replace the key switch by part number from the units manual, but I assume the replacement part id could be wrong. I will look into the specific part that I ordered and the OEM part to insure that the type is the same.
EDIT OEM 4406R - received STD365402
These seem to be the same type. I may have an issue with the safety switches or my ground. Looks like I am taking the entire harness out to trace everything.

On a second note if i have been provided the incorrect replacement from sears, what are the consequences of a bad magneto and how would i test to isolate that diagnosis.
Thirdly I have already replaced and connected the safety switch on the seat and ordered the replacement deck switch.

Last my intention is not to by pass safety mechanisms, because my wife will use the machine and I don't trust her to not make a mistake due to inexperience.

Thanks again for the input.

 

[chance123]

If the engine will run, your magneto is fine. There are many key switches that look identical but have a different configuration inside the switch.

 

[EngineMan]

You have a bad switch or a wire in the wrong place, have you got numbers on the back of the switch or does it go...A B C etc post up what you have with the colour of the wire's that are on them.

This may help you.