If you have "ignition power", I think you need to learn how these engines operate.
Does your walk behind mower use "ignition power"?
That's a hint.

It sounds like you put 12V to the coil and probably fried it.
The wire to the coil is GROUNDED to KILL the engine.
It should NEVER have power applied to it.

you lost me a bit bill,

we have not applied power as you say, my walk behind is a good simple model no fancy gismo's it is over 20 years old original squat 4hp b&s. still starts no more than 3rd pull, uses no oil. i'm sure way back when i would have lifted the flywheel and replace mechanical points with after market b&s electronic ignition.

any help in getting this flywheel off will be greatly appreciated, reckon my friend will buy a local simple rider next time none of that foolproof stuff to make them unreliable.

if coil is danged maybe last person who tried jumpering past everything did that? all we've done is loop past those safety solenoids.

tia

len

Then just EXACTLY do you mean by "ignition power"?

Apparently, we're separated by a common language.

Well "Igniton Power" is a good question, I don't know what you mean either but there is nothing under the flywheel that has anything to do with your ignition. As Bill said, You do NOT want any battery power TO the ignition coil. There probably are two wires coming from under the flywheel, both are from the alternator.

To see if you have ignition trouble, find the "Kill" wire, disconnect it before it goes under the cooling shroud and see if engine runs. IF it does, problem is back up stream in safety switches OR ignition switch. IF not, problem may be with Kill Wire between connector and ignition coil OR the Ignitions coil.

Walt Conner

sounds simple to me that is the power we get when we turn the ignition switch, so the ignition works and turns the motor over but there is no spark to the plug the plug spark is not known as ignition spark. so on a rider with electric start there are 2 electric type conditions one is spark to the spark plug, the other is to activate the starter simply and only to start the engine instead of a pull cord manual starter being used.

how's that sound now bill?

walt we now don't have starter ignition problems. yes 2 wires from under the flywheel, and there is a wire plugged into the coil externally. all safety switches are bypassed.

need to point out some other person had run some sort of jumper wire and started the motor that way but it then stopped and could not be restarted, we have removed that wire. so any damage to the coil would be before we got the machine to look at. all we want to do is some saving grace for the owner/friend, who rues the day he bought this make and model.

len

"and ignition power"

"Apparently, we're separated by a common language."

"sounds simple to me that is the power we get when we turn the ignition switch, so the ignition works"

First off, as has been said before, you do not want any power to the ignition from any outside source. The ignition is totally self contained and operates merely from the flywheel turning fast enough. Power from the ignition switch has nothing to do with it other than run the starter making the flywheel turn. The wire to the ignition switch is a "Kill Wire" shorting out the ignition to stop the engine. ANY momentary exterior power to that wire will destroy the ignition coil. IF you unplug the "Kill Wire" at the base of the coil and the coil then does not produce a spark, the coil is shot. This needs to be followed exactly. There is a slim, very slim odds chance, that the surface the coil is mounted on is corroded so ground is not established OR that the flywheel magnet is bad (never had one)

Walt Conner

Walt said what I would have.

I never call it the "ignition switch", because it ISN'T 98+% of the time.
I call it the KEY switch.

Len, the ignition system is a completely independent and self powered entity. The magneto coil (Briggs calls it an armature) generates its own spark making energy as soon as the flywheel rotates as the magnet in the flywheel passes by it.
There is not any power coming from the key switch to the magneto.
There is however a "kill wire" which serves to connect the magneto to the chassis of the machine in order to cause the spark making process to cease and thereby "kill" the engine.
The kill wire can be controlled by several components of the tractor depending on the brand and year model.
Typically there is a circuit in the key switch that controls whether the magneto is grounded or not.
There may also be other switches in the safety interlock set up that will kill the engine under certain conditions.
As has already been said, you can unplug the kill wire from the engine to see if doing that allows spark to return.
If that does not help then you must disconnect the kill wire right at the magneto itself. If disconnecting the kill wire at the magneto does not give you a spark then your magneto is defective.

yes i am converfsant with teh sparking magneto systems of mowers, so when it was suggest that somehow 12 volt power got to the coil i got lost.

like in cars there is 2 systems:

ignition system is where a key is inserted and turned to start the motor

then there is the spark system where an alternator provides power or power is provided to a coil and in old days a mechanical points and condenser system through a distributor. nowadays that has been replace by electronic, like briggs did 20 years ago about.

the ignition system always has been what starts the motor and provides power to accessories etc., simple hey?

so now i need to lift flywheel so we can attempt to find out why we don't have spark, that means there is no current to the spark plug.

so now how to lift this flywheel never had any issues with older model briggs's.

there is a plug socket near the carby that is not plugged in we cannot find any cut off to ground type switch like all b&s motors had that i ever worked that included electric start australian models started by exactly the same key key start except none of that safety stuff that makes mowers from say the US unreliable.

so if we are now in the same ball park are we able to move on? and get this machine running for this bloke?

so bill when key is turned it causes ignition which operates the starter to turn the engine over. starter switch or ignition switch one and the same.

len

Is this for real?

Walt Conner

I give up!

so no help hey, confused the question with local science, i've re-read what i said and to me it is simple. but others seem to want to complicate it, it is ok to say you have no idea how to get the flywheel off, i won't laugh at you.

that is where the question is at removal of the flywheel nothing else ok!

in previous replies in one breathe one of you said that 12V power goes to the coil, in the other breathe another said there is no 12V power going to the coil, that does make sense.

so keeping it simple any clues on getting this flywheel off please? are they still on a conicle shaft?

len

http://www.youtube.com/watch?v=KkaD3h8J6es&feature=fvwp&NR=1

Nobody said you need 12 volts at the magneto.
The magneto makes its own electricity.
The wiring that DOES connect to the magneto IS NOT 12 volt power! It is a grounding circuit to provide a means of stopping spark when you want the engine to quit running.
You must grasp that the key switch can provide 12 volt power to some circuits that require 12 volt power and at appropriate time also provide a separate function of grounding the magneto to stop the engine. The key switch has multiple circuits inside and the power circuits are separated and insulated from the ground controlling circuits.
Did you attempt to follow the simple suggestions for testing the magneto?
And for the last time......there is nothing under the flywheel associated with the spark making process.

You very knowledgeable gentlemen are waisting your breath, The OP is convinced he understands the electical system and that the points and condenser are beneath the flywheel. He IS going to remove the flywheel. He now has a video explaining how. He'll be back again shortly.

I do have one question for gardenlen:

Where does the electricity for the spark on your push mower come from?

grass,

the coil points system, nothing whatsoever to do with starting the engine same in a car. by the way my briggs is around 20 years old and long ago when i had the opportunity i replaced the mechanical points with a B&S after market electronic unit DIY, that would be around 15 years ago and all i do is change oil twice a year, keep the sponge filter cleaned and drop in a new spark plug each season.

yes mownie, exactly then why did a poster earlier on say that the 12 volt had damaged the coil?

dunno what is trying to be proved here, so to bring all this to an end as i said earlier we worked on teh ignition part of teh electric start, and we have that working.

now the coil/electronic ignition is not supplying a spark as i said earlier, and yes having been under many briggs flywheels to replace points or fit after market electronic units that is where i need to go to determine what to do with the electronic spark ignition is not working.

this flywheel is not going to budge without a substantial puller, so it is back to the owner who has been without this unreliable machine now for 9 months, so his options are mortgage the house maybe (he is very low income poor type person, why i took the task on against my better judgement and the treatment here supports that).

we obtained a wiring diagram offline for the briggs, that says that what we have done so far with the ignition side of things is fine.

so where there was an opportunity of online help that has now vanished, i've said what the current status is we have neither fixed it or made it worse, the owner is still broke and without a retched mower he should never have bought.

so i'm outa here

good luck folks

len

OK. I got to feeling bad and decided to get out of bed and post this as I hate to see Len waste his time and possibly do damage removing the flywheel. I've read this thread a number of times and I think I understand what mownie, bill and walt are saying and what Len is not catching.
Len, your posts indicate that you understand that your pushmower creates electicity from the magnets on the flywheel and the magneto attached next to the flywheel. Years ago the electicity created by the magneto was sent to points and condensor that were located under the flywheel. In 1982 or 83, small engine manufacterers did away with mechanical points and replaced them with the electronic ignition (you also seem to know this). They combined the electronic ignition unit with the magneto and B&S calls this combined unit the magnetron. It is still in the same place as the magneto--on the outside of the flywheel. So riding mower engines, whether they are 12 hp or 28 hp operate'spark just like the engines on any pull start gas engine.
Now most people don't want to pull start engines, especially larger engines, so the manufacturers decided to put starter motors on them. To run the starter motors they had to have a battery. Then they determined that they had to have a way to charge the battery or it would go dead, so they added an alternate under the flywheel that would be turned by the engine to generate electricty to recharge the battery. Then they decided that since they had all this electric power they would add lights etc. I don't know why they didn't decide to use this eclectricity from the battery for the ignition/spark plug spark like in a car, but they DIDN'T. They still use the system used on any small gas engene to procuce the spark. So there are two separate electical systems, neither has anything to do with the other.
If you follow the advice given here, you will be able to determine why there is no spark at the spark plug. Take the flywheel off if you want, but it's a waste of time and you will need to buy the tools if you don't want to damage the engine.
Once again, other than the addition of the electronic ignition magnatron, the tractor's engine works the same as any pull start engine that you are familiar with--just no points or condenser under the flywheel anymore.

Hmm , well the OP posted while I was composing, I just don;t understand how someone who seems to understand how ti all works, doesn't understand how it works. But evidently it's all you fault gentlemen, so a pox on you for trying.

***"when key is turned it causes ignition which operates the starter to turn the engine over"***
I think the primary problem here is in semantics, as illustrated by the statement above.
A lot of folks might think that the above statement is an accurate description, but....alas, it is not.
The word "IGNITION" (and thus Ignition system) actually refer ONLY to the components that work to manufacture the spark in the spark plug.
The starter motor and starter solenoid are not components of the IGNITION system but instead are in the CRANKING system grouping.
And to give one more distinction to the semantics of the trade, Diesel engines DO NOT have an actual IGNITION system per se, but they do have a Cranking system.
Now, as to why the implication of "12 volts to the magneto" was mentioned...........It will never be known how many magnetos have been ruined because someone connected the kill wire to a battery power source in a misguided attempt to figure out why they were not getting a spark from the ignition system. This has happened enough that that most small engine technicians and parts personnel can relate numerous examples/stories of such. So when a poster comes on here and admits to being baffled by the (seeming) complexity of an electrical system, it seems prudent for us to go ahead and make it clear (or at least try to) that 12 volt power should never be connected to the magneto.

did say i wasn't coming back forgive me for that but:

ignition system

all starts at the ignition switch to start the motor, until an attempt is made to start an engine the coil, points system distributor have no part to play.

so when you put your key into the ignition switch of the car that is the very first step, on a pull start mower nothing happens until the starter is engaged and the flywheel is rotated past the coil stator plate. so the ignition starter of new mowers mostly due to larger engine sizes take place of the starter cord.

anyhow i'll leave that with you lot, i do need to get the flywheel off so we can very possibly replace the electronic points system and/or coil(not sure if you are aware but a coil can't be tested or replaced until the flywheel is off)

in this case there are 2 wires that go to the starter ignition switch, they have not been tampered with as we can see. like when i put an after market B&S electronic points system onto my once mechanical points motor, the flywheel had to come off.

now i don't know how over there you check the spark system without lifting the flywheel maybe you all have X-ray vision like superman??

anyhow thanks for the non help, if the owner of the mower wants to go further he is going to have to take it to a mower mechanic when he can afford it.

len

Hmmmm. This sounds familiar somehow. Anyways, there are no ignition components under the flywheel (at least parts that make the spark plug spark :) of a modern Briggs and Stratton engine. Under the flywheel is a stator that creates the current necessary to to charge the battery. Should you be at a crossroads and your engine cranks over, but you have no spark at the spark plug- either a switch or ? is supplying a ground to the small terminal of the ignition coil or a defective coil / spark plug. One can slide the small terminal off the coil temporarily to see if the coil will produce spark when the engine is cranked. If no spark, then the ignition coil is defective. Briggs calls them an armature BTW just to confuse the issue even more. 492341 is the part # for the engine #s you supplied. You'll know it when you see it as the cable that is attached to the spark plug is glued into it....

I obviously mispoke when describing the operation of the alternator/stator under the flywheel, I hape this does not furthaar muddle the issue.

MAN.....JUST UNPLUG THE WIRE ON THE BACK OF THE COIL!! IF WIRE ON BACK OF COIL IS UNPLUGGED AND YOU DO NOT HAVE SPARK, THEN THE COIL IS BAD!! ITS SIMPLE!!!! EVERYONE ON HERE HAS TOLD YOU THAT THE ONLY THING UNDERNEATH THE FLYWHEEL IS THE ALTERNATOR WHICH ONLY RECHARGES THE BATTERY, AND HAS NOTHING TO DO WITH CREATING A SPARK PERIOD!! ITS ONLY CONFUSING BECAUSE YOUR MAKING IT!!!

sorry just can't help myself, but won't resort to yelling in online terms.

with all of you resident experts, and i have lifted flywheels on electric start motors many time yes i am away the charging stator is under there but and this is a big BUT? do they only now sue a coil and no points condenser be it mechanical or electronic to cause the spark needed?????

refer to basic diagram in link i provided early on.

at this time we can't test or determine if coil is damaged then as was pointed out that some one put 12 volts into it then that was withdrawn, because i can't see that anyone could do that.

sorry to say also i am not making anything confusing i have tried to talk in simple terms, that's all i can do, and you all seem to have judged though over the years when a mower mechanic i would have lifted flywheels off of at least 1000 b&s not counting kirby lawson/techumseh, victa, villiers 2 & 4 strokes and some other models of engines foreign to australia.

now the B&S motor may be a US engine from wisconsin but sadly the US does not own it, it is used world wide, did a great job in WW2 for many small stationary engine applications, still runs my push mower after about 20 years.

in all that time we replaced very few coils they are a good strong coil so few in fact i could not even come up with a figure, yes i have lifted flywheels on B&S motors to replace point/condenser set up and when the plunger bush (was weakest link in briggs's wore because owner did not change oil enough, we reamed out the original bush an popped in a brass bush.

later on when briggs bought out their great electronic points/condenser system commonly called electronic spark ignition we then would seal off worn plunger bushes and fit this new device absolutely great invention to the degree i fitted one to my own machine.

so is there anyone here with the experience to tell me where the spark creator is? or is it contained somehow in the coil that looks like briggs coils have always looked.

all i want to do is get this mower a spark for the plug.

now if the electronic points/condenser is not under the flywheel and is not visible to my eye where is it.

just in case some help comes tia

len

When everyone else is crazy except you, might want to think about that just a little. I can send you a PDF of the Service Manual and you can look for your self IF you like but I have already given good advice which has been repeated by at least two others and I am done. Address below, put in proper format and remind me, model number and what you want.

Walt Conner
wconner5 at frontier dot com

"do they only now sue a coil and no points condenser be it mechanical or electronic to cause the spark needed?????"

Yes, If I understand walt, mownie and bill correctly, no points or condensor anymore and no separate electronic points anymore it's all one unit now --it's all circuit boards, microprocessors and the magneto all wraped up into one part that B&S calls the magnetron. It is not under the flywheel. You need to follow their advice on how to test the system.

The component that "times" the spark energy is in fact contained inside the magneto/armature/coil assembly outside of the flywheel.
The little package of electronic circuitry that does what breaker points formerly did is call (by Briggs)....the magnetron unit.
The spark energy is still produced just like it was in the olden dayes except that the timing of when a spark lets go is now done by the magnetron circuits buried inside the magneto coil.
Next!

Where's Rusty? Maybe he can understand him.