View Full Version : Riding lawn mower.....NO SPARK!


Keizer
07-26-2009, 05:32:24 PM
Ok, this is my riding lawn mower. I was using it the other day, and it was running great, just like always. I stopped to empty the bags, and then returned back to the mower. When I started it back up, it suddenly just died just like if you pulled the wire to the coil on your Camaro.

Anyway, I checked and cleaned the air filter. I pulled the fuel line on the other side of the fuel filter and had good fuel flow through the filter.

I checked spark, and was getting a little spark, but not a consistent spark every time the piston was at the firing cycle.

I bagged the troubleshooting, and just finished the lawn with the push mower.

So today I drained the fuel, and the fuel line, and added new fuel. I thought maybe I had bad gas. Again, it wouldn't start. So, I check spark again, and get a very intermittent spark, and then no spark at all from either plug. By this time I'm using the start feature on my battery charger, so I have plenty of torque to turn the engine over.

So, looking at my pic, can I assume I need the part that has the two plug wires coming out of it? If so, what is that part called?

Thanks for any help!! EDIT: I have re-sized the pic three times, and it just stays BIG........sorry.
http://img22.imageshack.us/img22/1619/img4772s.jpg (http://img22.imageshack.us/i/img4772s.jpg/)

ILLREGAL
07-26-2009, 05:52:43 PM
you meen the coil?

Twisted_Metal
07-26-2009, 06:00:52 PM
Do you wear a pacemaker?

Magnet still on the flywheel?

Hold the plug wire while you slowly rotate the magnet past the coil pick-up.
If the coil is dead.... You won't feel much.

A good coil/magnet will tell you to leave it alone. <- Pacemaker Alert ;)

79camaro2001
07-26-2009, 06:01:18 PM
it's a ignition coil.

Check the gap between the coil and the round disc so you can put the new one in the ballpark of where it needs to be. pull the coil off and replace it with a new one. set the gap to where the old one was located and hopefully it will fire off with no problem. Also might want to make sure the surface isn't rusted causing a bad reading.

If you can get the actual gap requirement from the lawn mower part store then I would use that one.

bbc nova
07-26-2009, 06:48:12 PM
Ignition Coil

Make sure to test the magnets on the flywheen and make sure they are magnatized. If they are get a new coil.

Replaced on on my lawn tractor earlier this spring. Call any small engine shop and give then the model # of the engines and they can hook you up. IIRC mine was like $50

Keizer
07-26-2009, 06:58:31 PM
Yeah, the magnets are good. I loosened the coil and turned the large wheel, and the coil sticks good to the magnets. I cleaned the outer part of the wheel with a small wire brush, as well as the coil......no go.

gordonquixote
07-26-2009, 07:35:55 PM
Kill/safety switch you possibly forgot about? Lots of riders won't spark unless you are sitting in the front seat.

Keizer
07-26-2009, 07:41:01 PM
Kill/safety switch you possibly forgot about? Lots of riders won't spark unless you are sitting in the front seat.

Nope, didn't forget the kill switch in the seat. All the testing is from sitting in the seat.

Are these coils either good or bad, or can they still spit out a random spark? I can get a quick spark every once in awhile, but for the most part.....no spark.

Knuckle Dragger
07-26-2009, 08:00:31 PM
That's a magneto Doug, and yes it can have a partial failure.

crazypurgatory
07-26-2009, 08:01:48 PM
Well I can't say for sure on the coil but If you getting week spark you might want to see if you can move the coil closer to the flywheel.
It's been a while since I messed with a coil I think you can move them to set the gap between the coil and the flywheel.
You can also go to briggs & stratton and down load a repair manual.
http://www.briggsandstratton.com/maint_repair/manual_and_more/index.aspx?buy
Well it's more like a parts list but you will have all the part numbers for your engine.
Good stuff to have in any case.:):)

Cardinal
07-26-2009, 08:18:31 PM
Actually, it's called a solid state. If your engine is a Briggs & Stratton it is a common problem for the solid state to quit when hot.

You can set the air gap with a $20+ tool OR use the box that the new solid state comes in to set it. Put the box between the solid state and the flywheel (where the magnets are) then tighten the screws.

79camaro2001
07-26-2009, 08:27:50 PM
Actually, it's called a solid state. If your engine is a Briggs & Stratton it is a common problem for the solid state to quit when hot.

You can set the air gap with a $20+ tool OR use the box that the new solid state comes in to set it. Put the box between the solid state and the flywheel (where the magnets are) then tighten the screws.


I used a business card to do this also, but I said to check the gap with a feeler gauge cause I know Keizer is more technical.

Keizer
07-26-2009, 09:37:13 PM
Thanks for all the info everyone. I got the Coil, Magneto, solid state, whatever it's called off the engine. I will take it to the mower shop this week and get a new one.

I did by pass that kill switch in the seat by just grounding out the magneto. I assume all the kill switch is doing is completing the circuit to ground when you sit in the seat. I wanted to see if mabe that kill switch was bad. Still no spark.

By the way, there is only one magnet on that flywheel.

rscamaro73
07-27-2009, 03:05:14 AM
If'n I was you, I'd have tried to dump a very little amount of fuel thru the air filter to see if it'd fire that way....in case the carb was jacked up.

Then again, if you don't have a heart condition or pace maker, I'd have tried the 'screwdriver' test :crazy: Its pretty much spot on. If you start cussing and THROW the screwdriver, its a HOT coil. If you drop it all and start cussing, its weak. LOL.

I'd also check your battery as well for a ground.....you must have a cheaper rider to have a coil mount like that. Just not like the Deeres I've been working on.

Keizer
07-27-2009, 12:21:13 PM
If'n I was you, I'd have tried to dump a very little amount of fuel thru the air filter to see if it'd fire that way....in case the carb was jacked up.

Then again, if you don't have a heart condition or pace maker, I'd have tried the 'screwdriver' test :crazy: Its pretty much spot on. If you start cussing and THROW the screwdriver, its a HOT coil. If you drop it all and start cussing, its weak. LOL.

I'd also check your battery as well for a ground.....you must have a cheaper rider to have a coil mount like that. Just not like the Deeres I've been working on.

I did shoot a little starter fluid in the carb with a no go. There was no way I was going to try the screw driver trick. Either you get spark from the spark plugs or you don't. I wasn't getting spark from the plugs, so it wasn't starting anyway. I also tried other plugs with no spark. The only other thing was the kill switch which I bypassed, and still no spark.

Yeah, this mower is about 14 years old. It's a Murray, with an 18 hp Briggs, and a 46" cutting deck. All I have ever done to it is a steering linkage, and a starter gear. These riding mowers will last a long time if all you ever do is mow your lawn with it. Once you start trying to cut an uneven hay field, or other nasty grassy areas, they start to fall apart.

John Wright
07-27-2009, 12:37:21 PM
Take some scotchbrite to the flywheel.....


..also make sure the key is still square in the keyway on the crankshaft...if it has started to shear you'll get irratic timing.

Keizer
07-27-2009, 12:39:41 PM
Take some scotchbrite to the flywheel.....


..also make sure the key is still square in the keyway on the crankshaft...if it has started to shear you'll get irratic timing.

Whatever this was, it gave up instantly. Like I said, it has always ran great, and was running perfectly the day it broke down. It was running, and then it was just like I turned the key off. The engine sputtered a few times as it was winding down and dying.

John Wright
07-27-2009, 12:41:34 PM
the key problem is usually with push mowers when ya hit something that stops the blade

rscamaro73
07-27-2009, 04:45:11 PM
Time to get this thing fixed as its prolly something small.

If you're SURE its spark related, it'll be the coil deal there. Make sure there's not a separate ignition module as well. I see lots of Deeres with them. I have at least one I need to change out still (pop's).

Anyhows...if I was you - and spending your money - I'd still get that part number and do a net search and see if you can find it somewhere online, as its usually cheaper that way. At least for J.D. parts. Can't see paying $5+ for a $1.50 fuel filter :rolleyes:

Did some homeworks for you though....when you put the new coil on, make sure its the correct "this side up"....and the ground strap goes on before the coil gets fastened down, along with the proper gap. Found this same issue online and a new coil wasn't working....so make sure orientation is done properly....and that you've 'tested' it....4500 ohms resistance....and spinning it over with the starter. Mags in the flywheel shouldn't be bad if a nail sticks to it.

Also - post up the part # on the coil and I can see what I can do for you...

Lastly - here's some info to looks at - http://faqs.custhelp.com/cgi-bin/faqs.cfg/php/enduser/std_adp.php?p_faqid=3761

Parts lists - requires engine model # - http://www.briggsandstratton.com/maint_repair/manual_and_more/

Check this to see if its close - price wise its decent. - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180376314302 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180376314302)
Part lists for $50 on the B&S site.

Amazon has a seller with it as well for under $30. - http://www.amazon.com/Replacement-ignition-Briggs-Stratton-394891/dp/B002HPZ678

Even cheaper (and maybe closer) for $21 - http://cgi.ebay.com/Replacement-Ignition-Coil-for-Briggs-Stratton-394891_W0QQitemZ110414353344QQcmdZViewItemQQptZLH_DefaultDomain_2?hash=item19b53553c0

http://cgi.ebay.com/BRIGGS-STRATTON-TWIN-CYLINDER-IGNITION-COIL-394891_W0QQitemZ390074391468QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item5ad23edbac

BowHunter
07-27-2009, 07:23:31 PM
I had a friend who had the same problem and it was the seat switch! He thought he had bypassed the switch but it still would not start!
He went to a shop and they told him to replace the seat switch he did and she fired right up.

rscamaro73
07-27-2009, 09:56:19 PM
I had a friend who had the same problem and it was the seat switch! He thought he had bypassed the switch but it still would not start!
He went to a shop and they told him to replace the seat switch he did and she fired right up.

That's what I am hoping it isn't......because it'd be a PITA if it was....lol.

You can tell when the starter kicks over if the seat switch is depressed. Starter won't kick over at all if it isn't (unless you jump the starter terminals).

Keizer
07-27-2009, 09:59:12 PM
Ok, I took the coil into the local mower shop and they tested it for me. They said it gave out one jolt, but nothing that was going to start the mower. They had one in stock for $55.00, so I bought it. I also got a set of new plugs.

The instructions said to place the coil .010"-.014" away from the flywheel. So, the business card worked perfect for this.

Anyway, it fired right up first try and runs great!!!

I also replaced the fuel lines since I had it apart.

Thanks allot guys for all the help. And rscamaro73, thanks for all that info. I just now saw it as I was extremely busy today and away from the PC.

Keizer
07-27-2009, 10:01:52 PM
That's what I am hoping it isn't......because it'd be a PITA if it was....lol.

You can tell when the starter kicks over if the seat switch is depressed. Starter won't kick over at all if it isn't (unless you jump the starter terminals).


It would be so easy to bypass that seat switch. All it does is completes the circuit to ground. You could easily just connect a wire to the coil, and straight to ground and it would stay running. I am actually thinking about doing that because it would save wear and tear on the starter gear.

Cardinal
07-27-2009, 10:18:58 PM
I wouldn't bypass the seat switch. A guy up the road from me did. Mower rolled over and kept going. Damned near killed him. It's a safety interlock that's there for a reason.

rscamaro73
07-28-2009, 02:40:07 AM
I wouldn't bypass the seat switch. A guy up the road from me did. Mower rolled over and kept going. Damned near killed him. It's a safety interlock that's there for a reason.

X 2. Its stories like that - that make me leave things like that alone.

Glad you got fired back up and cutting again :) Good job.

Marks71BB
07-28-2009, 02:52:05 AM
I bypassed the seat switch when I brought my riding mower home and never looked back.Common sense tells ya to disengage the blades and put it in neutral befor ya get off.

Glad ya got it fixed Doug. imho Dave is correct, its a magneto, the simplest form of ignition.

John Wright
07-28-2009, 08:43:41 AM
Glad you got it going Doug.......none of my mowers have any of those switches working anymore.....they are troublesome, so when they quit working, rather than replacing them, I just jumped them out....Like Mark said, a little common sense goes along way. Might be a different story if my kids used these mowers though.

Keizer
07-28-2009, 11:40:50 AM
Glad you got it going Doug.......none of my mowers have any of those switches working anymore.....they are troublesome, so when they quit working, rather than replacing them, I just jumped them out....Like Mark said, a little common sense goes along way. Might be a different story if my kids used these mowers though.


Yep, I'm real big on common sense, and have always considered that seat switch a pain more than a safety feature. My lawn is huge, and I probably start and stop (kill switch) the engine a dozen times during a mowing to empty the bags.

The starter gear is nylon so it doesn't damage the flywheel gear. But, eventually the starter gear gets mangled from all the starting.

John Wright
07-28-2009, 11:59:53 AM
I hated that switch under the seat that disengages the blades....on a rough yard, if you bounce over the bumps you can disengage the blades, if the pressure on the seat isn't enough to keep the switch made.

Keizer
07-28-2009, 12:20:03 PM
I hated that switch under the seat that disengages the blades....on a rough yard, if you bounce over the bumps you can disengage the blades, if the pressure on the seat isn't enough to keep the switch made.

My seat switch doesn't disengage the blades, it shuts the engine completely off. If I get out of the seat, the engine dies. That's why I am always starting the engine up, because I have to get off the mower to empty the bags.

Twisted_Metal
07-28-2009, 12:27:52 PM
The seat switch on my mower kills the engine too.
I have a couple of steeper areas in my yard which are difficult to mow with yer butt planted correctly.

I left it in place cuz I don't have enough sense to know how dumb I can get. ;)

79camaro2001
07-29-2009, 09:43:17 AM
Actually the reason for the seat switch is if you are riding along a hill and you fall off somehow, then the mower will kill it's self instead of still be running. This is so you don't get ran over by the mower or if the mower fell on you then it will kill the mower before it topples on you.

John Wright
07-29-2009, 11:30:12 AM
Actually the reason for the seat switch is if you are riding along a hill and you fall off somehow, then the mower will kill it's self instead of still be running. This is so you don't get ran over by the mower or if the mower fell on you then it will kill the mower before it topples on you.My point...if you used a tiny bit of common sense and saw that the hill was a bit too steep to safely mow for the fact that the mower could turn over...why mow it with that mower?, use a push mower or weed eater....right?..so how does that switch under the seat keep you safer if you use your head for something other than a hat rack?

rscamaro73
07-29-2009, 12:04:00 PM
My point...if you used a tiny bit of common sense and saw that the hill was a bit too steep to safely mow for the fact that the mower could turn over...why mow it with that mower?, use a push mower or weed eater....right?..so how does that switch under the seat keep you safer if you use your head for something other than a hat rack?


Lets just go back to the old saying " If common sense was so common, EVERYONE would have some " :crazy:

Wouldn't be Darwin recipients if there wasn't a lack of common sense :p

mike261
07-29-2009, 12:10:51 PM
that switch is a pita, I put a toggle switch with one of those red aviation style levers on top. I can overide the seat when i get off the mower, and if i forget to deactivate it a quick slap will turn it off if im rolling over.
mike

79camaro2001
07-29-2009, 03:58:32 PM
My point...if you used a tiny bit of common sense and saw that the hill was a bit too steep to safely mow for the fact that the mower could turn over...why mow it with that mower?, use a push mower or weed eater....right?..so how does that switch under the seat keep you safer if you use your head for something other than a hat rack?

Say someone decide to play a prank with you and digs a hole in your yard, but also put the grass back in place with a layer of plastic to hold it up. You riding along and your front tire drops in the hole causing you to start falling off the lawnmower and you end up in front of it when you nose dived to the front.

Where's common sense then! LOL Safety devise are placed in their position for a reason MOST of the time.

Kind of like the derrick hand whe was wearing a harness but didn't hook up to the safety cable while he was up in the air. He never fell off the derrick so why do he need to hook it up, it's just getting in his way!

crazypurgatory
07-29-2009, 08:24:36 PM
Say someone decide to play a prank with you and digs a hole in your yard, but also put the grass back in place with a layer of plastic to hold it up. You riding along and your front tire drops in the hole causing you to start falling off the lawnmower and you end up in front of it when you nose dived to the front.

LOL they did that in one of the JackAss videos.