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Started running rough so i replaced gas filter, nothing, spark plugs, nothing getting good spark, went thru carburator fires right up run like it running on one cylinder pulled left plug out to check spark and the mower fired up running the same way ?

You already figured it out. replace the left coil.

Two part numbers come up.
394988
394891
You will have to look at the part and decide what one is yours.

:welcome:

That engine is getting a bit long in the tooth now.
So a few things will start creeping in if the mower has not been properly serviced.
Check each cylinder by pulling the plugs 1 at a time.
If the engine runs the same with one plug removed then that side is the problem.
This model has a double sided coil so you need to earth out the removed plug.

As they get on the head bolts loosen a little bit and the head gaskets blow.
Also check the valve lash as by now it has probably opened up a long way

You are not changing the left coil but both coils. It is one unit for both spark plugs.

BlazNT said:

You are not changing the left coil but both coils. It is one unit for both spark plugs.

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Mate, this is a double ended wasted spark coil,
No way can only one side spark it is either both or nothing.
You get a + spark on one side and a - spark on the other.
Bp\oth plugs fire every revolution.
Next time you get your hands on one stick an induction tach on it a see what it reads .
A 7000 rpm Briggs, yeah right, hod me stumped whn trying to tune the first one .

bertsmobile1 said:

Mate, this is a double ended wasted spark coil,
No way can only one side spark it is either both or nothing.
You get a + spark on one side and a - spark on the other.
Bp\oth plugs fire every revolution.
Next time you get your hands on one stick an induction tach on it a see what it reads .
A 7000 rpm Briggs, yeah right, hod me stumped whn trying to tune the first one .

Click to expand...

Yep and wires never go bad. Maybe I should have trouble shot this a little more but I have seen it a lot in this type of coil with cars. One cylinder no spark and move the spark plug wires and it follows the wire. Replace the wires and spark come back to all cylinders. I will step out of this one.

BlazNT said:

Yep and wires never go bad. Maybe I should have trouble shot this a little more but I have seen it a lot in this type of coil with cars. One cylinder no spark and move the spark plug wires and it follows the wire. Replace the wires and spark come back to all cylinders. I will step out of this one.

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Cars have a kettering type ignition not a magneto type ignition.
If you have a polarity sensative induction timing lamp you can check this because the pick up has to be put back to front to get a reading on the - spark wire.
It is a single circuit with a spark plug connected to either end of the coil and the windings in the middle.
If one end is open circuit the whole thing is open circuit.
If both spark leads are connected to the same end of the coil, the one with least resistance will get all the spark and the other will get none.
You know electricity will follow the path of least resistance.

Some coils have an internal resistor so if a wire goes open circuit there is still a complete circuit but these are way too expensive for a lawn mowr.

Well I learned something today.

BlazNT said:

Well I learned something today.

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And the day I stop learning will be the day they toss me in a 6' hole and urinate on the box I am in.
You canget a clever device from farm suppliers that tells you which way the electricity is flowing through a wire ( never seen one in an electricians supplier ) .
It is designed for grasiers in places like Arizona where you can have 100 miles of electric fence and can not walk it daily to check for faults.
The landlord has one and I ge to play with it now & then, lots of fun.
When I use to do it in the dirt, we fitted about 60 Runtronics ignitions to th dirt bikes and they have the same type of output coil, double ended + one end - the other.
Even more interesting is they use a cluster spark at low revs which really sent the impule tach crazy.

I agree. I'm not dead so I am learning. Only a few pompous asses think the know everything. I have not seen many of those on here that help. Just some that need help. They tell us what it can not be and it normally turns out to be the problem.:laughing::laughing: