Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

spark plug


thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-27-10, 11:02 AM   #1  
spark plug

Does the term mm-1 on a spark plug mean anything to anyone and what kind of voltage/ampage does a typical lawn tractor spark plug need to spark?

 
Sponsored Links
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-27-10, 11:44 AM   #2  
Not sure about the mm-1. That could be a thread pitch.

It takes about 30,000 volts for a spark plug to spark. Some are different with resistors setup in them.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-27-10, 04:00 PM   #3  
what kind of ampage does it need?

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-27-10, 05:20 PM   #4  
Not a lot. It's more of a voltage consideration. All you're doing is showing a spark. Amperage is work load stuff.

What are you working on?

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-28-10, 07:47 AM   #5  
What are you working on?

An old lawn tractor that is missing a battery and gas tank. I decided to take out the electrics (minus the spark plug lead) and when I hooked up a lawn tractor battery (12v/ 275 amps) I got quite a spark, telling me that there was too much ampage in the circut, so I was wondering how much ampage I need. I got a .5amp 12v battery. Would that work?

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-28-10, 08:20 AM   #6  
Edit; when I say lead it was the wire that came from the key and then went to the voltage control that later went to the voltage control center.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-28-10, 09:15 AM   #7  
It depends on the mower. If it's one of the much older ones with the battery fed coil the amperage of the battery would be insignificant.

What would cause your problem would be the voltage. Normally there would be a resistor in the circuit somewhere. That could either be an external resistor to cut the running voltage, often with a by pass for starting or an internal resistor in the coil to cut the voltage all the time. That's done for the coil and points.

Cutting to 6 volts running or 9 volts running is pretty common.

Should you put a 12v battery on a coil not compatible with the 12v, it would run for a short time, then burn up.

Systems using the 12 volt reduced allow for the 12v battery to turn the starter and the 12 volt charging system, which is a little faster recovery.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-28-10, 09:44 AM   #8  
Well, what I am working on is a simplicity 3415s lawn tractor what should id do as far a battery and spark system. I guess ill try the system with the half amp 12v batteryand see if I get a spark. I did not get a spark however with a nine volt.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-28-10, 10:10 AM   #9  
See what you have in it for a coil. It should be marked as having an internal resistor. If it does, use a 12v battery or whatever amps you have handy. A 9 volt battery going through a resistor wouldn't get you a spark, if you're using one of the little radio batteries.

If the coil isn't marked as a resistor coil, go to an auto parts store and get an in line resistor to cut the 12 to 9 and use the 12v/275amp battery on it. If you go this route, don't bother with a bypass for the starting circuit.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-28-10, 10:24 AM   #10  
Well, in the mower there is a box with three sets of coiled wire that I am guessing does what you were talking about. The direct in for the battrey goes in to the first coil and off the last is the headlights ect.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-28-10, 12:12 PM   #11  
That is a resistor, but for the headlights, not specifically for the ignition coil. Trace the wire from your ignition switch to the small negative post on the ignition coil. Between those two points you either have a resistor like you have for the head lights or an ignition coil with a resistor inside it.

The ignition coil is the thing the spark plug wire comes out of to go to the spark plug. That's not the same thing as the head light coil you're talking about.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-28-10, 09:05 PM   #12  
the thing is that there was a device that came from the battery that was labled "shortstop" with the markings "12v, 20amp" would that device bring down the amperage or is that what it can take and the box that i was talking about earlier had multiple points were you could attach a wire which i am assuming is different amperages for different components.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-28-10, 09:09 PM   #13  
also, i believe that there is a missing component there because there used to be an ignition switch between the key and voltage control (for the spark plug) so what I am more or less trying to do is replace that parts function with the ones i already have.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-29-10, 06:47 AM   #14  
The 12v/20amp would a relay or fuse to protect the circuitry. The block you described earlier with the coils of wire and the different connecting point on the down stream side from the battery/block would be a resistor. Since its has multiple connecting points on the down stream side that could very well be serving to cut voltage for everything you need.

The issue on this stuff is voltage, though. That's the thing that's being reduced, not amperage. A device one pulls amperage in the amount needed to run the device. Think in terms, voltage pushes and amperage is drawn. Too much voltage and it pushes its way through the device and destroys it if the voltage is too high. Have all the extra amperage you want, the draw of the device regulates it.

If you have the resistor block in the circuit, check the connecting points with a volt meter, especially on a terminal marked "ignition". If one isn't marked, check all them. They all may be the same, but find out what the voltage is.

The outbound voltage from that box has to match the voltage requirements of the ignition coil. All you have to do then is switch the power from the battery to the ignition. You can put that switch in the circuit between the the resistor and the coil or, if you want to switch off all the accessories with the ignition switch, put the key before the relay/fuse (shortstop 12v/20amp).

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-29-10, 07:29 AM   #15  
well, if its a question of voltage, would a light in the circuit bring the voltage down? also, you might find the owners manual handy (proceeding link)http://www.keepandshare.com/doc/2173...m-1-1-meg?da=y.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-29-10, 02:24 PM   #16  
A light in it isn't going to do a lot. Does that little tractor have a Kohler 8 or 10 HP engine in it? If not, what is the engine model?

Also do you have the power accessories shown in the manual?

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-29-10, 03:17 PM   #17  
Actually, its a 15hp briggs and stratton engine. What do you mean by power accesories?

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

08-29-10, 03:47 PM   #18  
It's showing a power lift and the generator/starter in one component. It's also showing safety switches.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

08-29-10, 04:36 PM   #19  
Well, have just about none of those of those components except I do have the gen light.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-10-10, 12:17 PM   #20  
Let's make sure of what you're working with first. Do you have a full sized coil = about four inches long with two small terminals and the center tower for the spark plug wire?

If you have that, have you found the points and condenser assembly?

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-10-10, 12:25 PM   #21  
I'm sorry but all I know is that I have the voltage control box and and the whole assembly inside the engime for timing and whatever else it does. Refer to the link for the manual that I gave you. That should help. As far as parts are concerned, assume that I don't have them except the box that has all the wires running towards it.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-10-10, 01:07 PM   #22  
That must have all the ignition components inside the engine. So the coil is apparently a semi-modern coil or a fully modern module. That manual isn't showing anything external to the engine except the starter/generator.

Get the numbers off the B&S engine and we'll get the ignition ran down. If that has the ignition I just described it should be simple to get a spark for you and get the thing started. The ignition switch will be no more than an off/on switch to kill the engine and switch the accessories.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-11-10, 10:45 AM   #23  
well, either the engine is so old the stickers have fallen off or I don't know were to look but I can't find any numbers on the engine. I did find a sticker that said easyspin starting but thats it. Here are some links as to what I could find online about it:
Nice 1971 Simplicity Sovereign 3415s Runs Great!
Simplicity Sovereign 3415 S 15hp lawn/garden tractor w/ 48" mower @ ListFox - Craigslist Local Searching

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-11-10, 12:31 PM   #24  
If yours is a 1971 with the original engine, it would have the coil with points and condenser separate. There's a couple of different setups for that. One is with the external tower type coil and the other is with the coil under the engine shroud. The tower type is pretty common with the K series Kohler engines, but since the manual you have linked doesn't show any of those ignition parts, I would assume the coil is under the shroud.

If you have a straight magneto type which is the coil under the shroud, the battery in the tractor would only serve to turn the engine over and wouldn't have anything to do with the spark. If you have safety switches under the seat, etc. those have to be dealt with as possible spark stoppers.

With all this in mind, where are you at on getting it to run? Have you got it started, or got it to turn over without it starting, or what is it doing when you do what?

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-11-10, 02:08 PM   #25  
where I am at as far as starting it? well, I have taken out all of the safety switches including those under the seat. I have taken off the starter motor and anything else that had a wire going to it except the wire that lead to the voltage control center. I plan to put in a pull start because I believe the starter is fried. In short, It really has no hope of starting without the spark. I have a few concerns, when you say condenser, do you mean this (scroll to absolute bottom of page)Hollywood's 1968 Ford Mustang Projects because those two parts i do have in the voltage control box, which i have the lead to.

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-11-10, 02:42 PM   #26  
That is a set of points and a condenser. Take a picture of the thing the spark plug lead comes out of on the tractor and post it.

What is the voltage control box you're referring to - the voltage regulator? That would have nothing to do with the ignition.


Last edited by marbobj; 09-11-10 at 03:03 PM.
 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-11-10, 04:37 PM   #27  
How would I post a picture from my computer or I could email pictures to you if you gave me your email.

 
Gunguy45's Avatar
Super Moderator

Join Date: Dec 2007
Posts: 20,653
AZ

09-11-10, 06:05 PM   #28  
http://forum.doityourself.com/electr...your-post.html

Click the link for info on posting pics


Vic
"I sometimes wonder how some people ever made it to adulthood..."

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-12-10, 08:12 AM   #29  
here is my photostream and pics;
Flickr: thedancingman4321's Photostream

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-12-10, 09:06 AM   #30  
Ok, that;s good with the photos. What you're showing us are the points and condenser. Take the engine pulley and turn it over by hand and see if the points (the two contacts on the arms by the little canister) move back and forth.

And just to make sure follow the wire hooked to the spark plug and see if it goes under the engine cover. If it does take that shroud off and take a picture of the little jobby the wire comes out of on the engine.

I'm pretty sure you don't have an external coil and if the mag coil is good and the points are clean and moving you should be able to get a spark and get that thing started. Keep in mind it's fairly old and will have to be cleaned up.

All this said and if the coil is under the shroud, you won't need a battery except for accessories (lights, electric start, etc.) If the engine is mechanically sound (and we'll look at that) you should be able to get it started.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-12-10, 09:32 AM   #31  
Well, if the battery is just for accessories, then why is there a brownish wire leading into that box

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-12-10, 10:06 AM   #32  
I'm not following what box (the one with the condenser in it?) and what significance you're placing on a brownish wire.

Get the information on the lead wire coming off the spark plug so we can confirm the ignition system you have.

An external coil requires a battery feed to the coil through some sort of resistor normally. Should the coil be under the shroud and mated to the flywheel (which I'm almost sure you have) the coil and points/condenser are a self contained ignition system once isolated from the ignition switch and safety switches.

With an external coil, wires coming from the points/condenser would lead to (1) the ignition switch to break continuity to the battery feed and (2) the coil to establish and break ground to allow for a discharge of spark from the coil. This not likely the system you have. I'm not sure B & S engines even used it. Cheese would have much more first hand knowledge of that.

The system you likely have would have a wire going from points to the armature coil at the flywheel and the other from points to the ignition switch. The latter would be a grounding wire for a kill.


Last edited by marbobj; 09-12-10 at 10:29 AM.
 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-12-10, 01:29 PM   #33  
What I mean by box is the voltage control box (the one I have taken pictures of). The significance that I am putting on that wire is that it was originally attacked to the key for the ignition

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-12-10, 01:36 PM   #34  
That isn't a voltage control box. It's a cover for the points and condenser. The wire goes to the ignition switch to turn the ignition on/off. The off position is the grounded or kill position for the engine.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-12-10, 01:43 PM   #35  
Are saying that if I wanted to I could just take off that brownish wire without it affecting the spark system for the engine(like I could still get it running without the wire)?

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-12-10, 01:54 PM   #36  
Assuming your coil is under the shroud, yes, that is correct, but it can't be touching anything. Still, we need more information on the coil for the spark plug - does the plug wire go back under the shroud of the engine.

*** The wire you're talking about, though, is the way you kill the engine once you have it running.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-12-10, 04:29 PM   #37  
Take a look back at my flickr page. I uploaded a photo of what is under the shroud, but there is just about no way I can remove the shroud without cutting it. Also, when I pulled it away from the engine, I noticed there was a device there but it appered to have an exposed wire

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-12-10, 04:36 PM   #38  
Also, the wire from the coil does go under the shroud. One problem, when I was attempting to remove the shroud, the pully wheel that you saw stops the shroud from coming off. The only thing holding it onto the axle of the engine is the friction that it has on the axle. How if any way can I get it off, preferably using basic tools and materials (wd40 esc. when I say basic materials).

 
marbobj's Avatar
Member

Join Date: May 2006
Posts: 3,658
IA

09-12-10, 05:48 PM   #39  
Don't bother taking the shroud off, that tells us what we need to know.

A small wire should be leading to the points from the same place as the spark plug lead wire. The other wire from the points is the one we already talked about - going back to the ignition switch.

As long as the points are clean and moving and the coil, under the shroud is serviceable, you should be able to get a spark to start the engine. First turn the engine over by hand - turning the shaft from the side of the motor. Watch the two points by the little canister in your picture and see if they open and close as you turn the shaft.

IF you have to replace the points/condenser they aren't very expensive, but yours may be OK if they are clean - but they have to move open and shut.

 
thedancingman43's Avatar
Member

Join Date: Aug 2010
Posts: 143
NH

09-12-10, 06:33 PM   #40  
well, the inside of that box with the condenser in it is about the only clean thing in the whole engine. There is a devicein the box that does open and close or should i say goes in and out disconnecting and then completing the circut. Question, how would i test for spark?

 
Search this Thread