Briggs & Stratton engine question – do coils just die suddenly?

I went to mow lawn last night and my Snapper self-propelled mower with 6 HP B&S engine wouldn’t start. I use this mower every time I mow lawn, this Snapper mower does the “trim work” around trees, flower beds, etc. It has started with one pull all summer, and basically its entire life for that matter. I think this mower is 20-25 years old, it was my grandfather’s before they moved out of their house and I bought it from him about 18 years ago.

Last night, I pulled it out of the shed, gassed it up and pulled the cord. Nothing. Checked all the usual items. Nothing.

So I pulled the spark plug and put the checker on. There is absolutely NO spark. The plug tip was wet, so it’s getting fuel, but there is no spark on the ignition testing tool at all. She’s dead as a doornail.

Do coils just up and die on B&S engines? I just mowed with this mower 6 days ago and it ran perfectly, not a miss or any clue anything was wrong.

I’ve checked the discharge safety switch and that’s functioning properly, so the spark isn’t being killed, it does not appear to be being made at all. I’ve replaced coils before on engines that were hard starting and running badly, but I have never had a coil just up and die on me between uses. Which makes me suspicious that either this can happen and I just don’t know it, or maybe I’m barking up the wrong tree and it’s something else?

Anyone have any thoughts? I mean thoughts besides “it was ethanol what done it. ” Obviously, we all know that ethanol is out there wrecking the planet, kidnaping children, committing terrorist atrocities, and kicking dogs, but in this case….

Grouse

I would guess bad non-oxy gas??? Like anything electrical, sometimes things go out without warning.. Trump/Clinton or the Bridgwater injury may also be to blame

Anonymous wrote:

August 31, 2016 at 3:26 pm#1637007
I would guess bad non-oxy gas??? Like anything electrical, sometimes things go out without warning.. Trump/Clinton or the Bridgwater injury may also be to blame

Thanks. You left out global warming, Zebra mussels, Indian netting, and DNR mismanagement as possible causes as well. May as well round up ALL the usual suspects.

Make sure you don’t have a mouse house in the intake or exhaust. Or some needed wire chewed through.

-J.

Not a real expert but…..Any coil can just go right now……and usually does..
I think

Take the top cover off and remove the coil and clean the fly wheel and the 2 sides of the coil with sandpaper, then put a piece of paper between the 2 and let them stick together then tighten back up pull the paper out and start it.

condenser wood be my guess.

yes,a coil can fail after running perfectly,have seen it numerous times.
even as old as that thing is,it is still new enough to have the integrated module type coil on it,so it is possible the electronic trigger in the coil has failed which will require replacing the coil assembly.

now,if it is older than you actually think it is,and it still has point type ignition,the points may be bad,I cant remember if briggs used a points push rod,or was that techumseh? anyway,it is possible that they are being held open by a sticky push rod,in fact,the push rod can be worn enough the points may not even be opening anymore.

if it uses the cam type points actuator,the rubbing block on the points arm may be worn completely away.
as mentioned in another reply,if it is point type ignition,the condensor may have given up the ghost as well.

if it does have the integrated ignition module type coil on it,and you have to replace it,pay close attention to how it is mounted as IT WILL NOT fire if mounted upside down,they are rotation direction sensitive,I know,I spent an afternoon many years ago trying to figure out why a new coil would not work after installation,now a days,they have a direction arrow painted or cast into the coil body.

let us know what you figure out.

Must have filled it with diesel or you got some ho2 in your petrol. That will get ya

no no no!! he sad it doesnt have any spark,he must of had too many toddies,got hungry and ate the coil wire and doesnt remember it!!

its those dang bloody marys I have seen recipes for on here that will get you!!

Thanks for the replies. Tonight I’ll tear into it and get the parts diagrams looked up to see where I stand.

If the coil is shot, then it might be game over for this mower. The one thing going right for this mower was that the engine was running well. Unfortunately, the deck was rusting and I had to do some welding this past spring to hold it together for another year. So with that issue, I’m not sure it’s worth even the $30-40 for a new coil to keep it running.

I hate to see good equipment die. This Snapper was the best mulching mower I’ve ever used. It shreds everything like fine tobacco and does such a great job that I haven’t bagged leaves for years. I just mulch them with the Snapper and they go away.

Grouse

I recall testing coils with a multimeter on a couple of engines. If the Ohms are out of line the coil is shot. The thing is, one time the test showed the coil as bad and it was an easy fix. The other time the resistance was in range but I determined later on that the coil was bad nonetheless. Long story short, that latter coil was going in and out of service while the engine was running (basically when it warmed up).

I’d do a little work on Google, check the coil with a multimeter, and if its bad see if you can find one online for a good price. Used ones come up on ebay all the time and work just fine.

Of course, if you want to use this as an excuse to buy a new mower I am fully supportive of that decision!

Lots of good replies. I would also guess it would be the coil. Bigcrappie suggested what I would try. Sometimes it is just a really gummed up flywheel, specially on lawn mowers. Another thing to check (not related to the coil) would be the float in the carb. Briggs motors are notorious for a sticking or faulty needle seat thus flooding the motor and keeping it from starting. I do not believe that is your issue, but if you didn’t crank it too much trying to start it and the plug was wet, I would be cautious about that. You can check if the seat is bad by smelling the oil. There will be a significant amount of gas in your oil if the seat is bad.

I have lost faith in Briggs motors and have recently sold off my last one. It was on my mud motor and it was problem after problem.

it sucks to go down in the cylinder index

Mwal

Ya grouse coils do just up and die, seen it many times on older outboards. I’ve unwound a couple coils and found a break in the windings. If the motor runs uneaven or starts hard its either the condenser leaking and isn’t holding its charge and the spark will be of a reddish tint and anything but blue, or the coil. The only way to tell is take the ignition pieces out and look at them. Burnt points will still produce a spark that you would be able to see on a multi meter. Not spark? its either the points or the coil. No points and a high output coil? its the coil or a break in the ground wire or plug wire thats on the coil, my guess from experience.

Well, I fixed the problem. I got a new (to me) mower. That’ll fix it all right.

I just couldn’t justify putting any more time into this mower. The deck is shot, the blade is shot, and now this ignition issue. Just not worth the parts just to prop it up for the rest of the season.

I found a nice, barely used Snapper on Craigslist. Must have been owned by someone with a very small lawn, it was hardly used and less than half the price of a new mower. Done deal.

Appreciate the help and comments though.

Grouse