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I have had an Ariens 16-h garden tractor with a single cylender 16 Hp engine. No problems for at least the 2-3 years We have had it. Last week it started and ran like normal. It always has started when I quit cranking and the motor starts coasting. I noticed this and it has never been a problem, I never had to diagnose it. Now I checked the spark and noticed this behavior. It does not even try to start even with starting fluid. Compression and all else seems normal, just not even a pop. Anyone have any experience like this? Where to start looking?

lets start with the model and spec of the engine on your mower. The 16 hp could be a K series, KT series, M series, CH or CV series, SV series. So without the engine info we are just guessing.

K series.

Assuming K341 then What is the specification number of the engine so we don't have to guess. Kohler used both a battery ignition and a magneto ignition on their K series engines.

Will have full information tomorrow morning, battery ignition. It's not here right now.

My suspicion is it is not sending power to the coil with the key in the start position. Could be faulty key switch, could be somebody replaced the key switch and now has the wrong switch. Never saw it with the battery ignition systems but is fairly common with the Kohler engines with the fuel shutoff solenoid not sending power to the solenoid in the start position but works fine in the run position.

No fuel cut off solenoid. No wires evident.
Model 341S
Specs 71109A
serial 8318085

mcostello said:

No fuel cut off solenoid. No wires evident.
Model 341S
Specs 71109A
serial 8318085

Click to expand...

My point was that the coil may not be getting battery voltage with the key in the start position, but is in the run position. Need to get the volt meter out and check for power to the coil in both the start and run key positions.

Yes, You have pointed Me in the right direction.

You have a + and - sign on the coil. What is connected to the + side of the coil?

Busy tonight, will begin diagnostics tomorrow, thanks.

I have checked the ignition switch and all works correctly. Black wire from switch ends up on the + positive side of the coil. With a test spark plug grounded to the engine there is no spark when cranking, VOM meter confirms this. When letting off the key there are several strong sparks shown.
I have done a little looking around and found no evidence of crossed wires. I don't know how many safety switches there originally were. There is only one on the hydraulic transmission and it works as expected. Where to proceed?

So you are saying that you have battery voltage at the + side of the coil while cranking the engine but don't have spark.

If the answer to IL's question is yes, is the black wire from the switch the only thing connected to the + terminal on the coil?

Did not check voltage to coil, just checked spark. Black wire is the only thing fastened to the coil RIGHT THERE. Every thing else is hidden under the battery tray. Will check these tomorrow. Thanks for the ideas.

mcostello said:

Did not check voltage to coil, just checked spark. Black wire is the only thing fastened to the coil RIGHT THERE. Every thing else is hidden under the battery tray. Will check these tomorrow. Thanks for the ideas.

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No need to check. Sometimes when points and condenser get replace a person might connect the condenser to the + side of the ignition coil and that doesn't work.

You probably have no voltage to the coil while cranking. Just a thought but has the ignition switch ever been changed? If so and it happened to be replaced with a switch for a magneto ignition that will cause issues. If you time it just right, they can work but over time things can change. With most magneto ignition switches, the run terminal goes dead when you turn to the start position. On an ignition switch for battery ignition, the run terminal will stay hot when you turn to the start position.

The switch has not been changed in My time with it. It is a 1978 model - 46 years old. I have only had it 2-3 years. More troubleshooting. Thanks, Mark.

Just wondering, was this the first and only symptom? Prior to this, was there no rough running, bogging down or anything like that?

So you think nothing never wears out?

Run an unswitched hot wire directly to the + side of the coil. If the engine starts and runs fine, you know all of the ignition components are fine. Now just find out why you aren't getting power to the coil while cranking.

This service manual may help you out. One thing you should know is that the timing on a Kohler K341 engine is not the same an other K-Series engines. You need to review section 8 of the manual. https://mymowerparts.com/pdf/Kohler...al-K91-K141-K161-K181-K241-K301-K321-K341.pdf

I hope it’s not the wire harness. That happened to me. It’s a pain to find and replace the bad one. Mine was one for the stator.

Looking at the service manual, one of the schematics (Fig 8-20) shows that the behavior you describe is normal.

If that figure applies to your machine, then you’re already done.

Sounds like the key switch is losing ignition contact in crank position.

I had this exact problem when I had replaced my ignition switch. Not realizing there was a difference I picked up a generic replacement switch that didn't supply power to the coil when cranking. It worked fine for years and even though it cranked longer it always fired up when I released the key. I never realized it was wrong till I had a problem with the replacement one.
As was mentioned earlier, run a jumper wire from the positive battery terminal to the + side of the coil and see if it starts.
Even if the existing switch is correct it can short out and not supply power as it should. I have worn out several thru the years and id bet the previous owners of yours had to replace it.

Not trying to simplify things but this actually sounds like a fuel problem.
Drain the tank, drain the carb, put in new fuel adding some Sea Foam, about an ounce to the tank. Rock tractor to mix, wait ten minutes and start the engine.
Has worked for me!

Jim Pritchrd said:

Not trying to simplify things but this actually sounds like a fuel problem.
Drain the tank, drain the carb, put in new fuel adding some Sea Foam, about an ounce to the tank. Rock tractor to mix, wait ten minutes and start the engine.
Has worked for me!

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That’s what I thought at first too, but he said he shot it with a little starter fluid and he got nothing. Normally, if it’s a fuel problem, it’ll at least fire and then die. But you never know.

No other symptoms, making unobtainable and repair parts in My machine shop makes Me VERY aware things wear out. I will try the hot wire to the positive side of the coil in an hour or two tonight.

If it is not getting a spark when cranking then all the fuel in the world will not fire (unless it's a diesel.) It will start when coasting. No spark until I let off the key and the motor coasts.

Can you post the model and serial numbers for the unit. I would like to see what the original key switch was used.

I just came up from starting the mower. I hooked up a live 12V wire and it turned over 2-3 times and started right up, which it has never done. So I bypassed the switch. Now I need to know which switch to buy. The Wife is very happy as this is Her mower.
Model 341S
Specs 71109A
serial 8318085

ILENGINE said:

My point was that the coil may not be getting battery voltage with the key in the start position, but is in the run position. Need to get the volt meter out and check for power to the coil in both the start and run key positions.

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We have to be very careful how we say this. If a coil gets battery voltage, it is blown in shot in under a second!
What happens is the kill switch tab on the coil is grounded to the machine when the key is in the opposition but of course not when it's in the start or run position or at least that's the way it's supposed to be.
We don't want anyone to ever shoot 12 volts to a coil because it will likely damage it and quickly.
Flaky switches do this all the time. This problem is likely a messed up switch if no one has messed with the wiring.
EDIT: I just found what kind of engine we're talking about and it has a automotive style coil with a plus and minus apparently so that's why I was confused.
I was thinking traditional lawn mowers and not old school tractors. lol
Maybe that's why the old guys always called them magneto's.

TobyU said:

We have to be very careful how we say this. If a coil gets battery voltage, it is blown in shot in under a second!
What happens is the kill switch tab on the coil is grounded to the machine when the key is in the opposition but of course not when it's in the start or run position or at least that's the way it's supposed to be.
We don't want anyone to ever shoot 12 volts to a coil because it will likely damage it and quickly.
Flaky switches do this all the time. This problem is likely a messed up switch if no one has messed with the wiring.
EDIT: I just found what kind of engine we're talking about and it has a automotive style coil with a plus and minus apparently so that's why I was confused.
I was thinking traditional lawn mowers and not old school tractors. lol
Maybe that's why the old guys always called them magneto's.

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Magneto ignition is a breed of it's own. Had a 7hp Wisconsin on a wheel horse years ago. You could take the plug out and turn it by hand at the spark firing point the mag would click. that click was 50K discharge. It has a pulley that you wrapped the starter rope around and my brother being smart planned on doing like they did the old briggs engines by holding the spark plug wire and turning it over slowly and the briggs ignition would bite you softly. Well my brother grabbed the spark wire and told me to turn it over slowly pulling the rope. so I did click, click, click,click. It got him 4 or 5 times before he could let go of the plug wire.

Have worked on the single, twin and four cylinder versions on Wisconsin engines over the years. Can be finicky sometimes. Same brother that got bit by the single 7 hp engine had a JD B that I hated. The compression discharge petcocks that had to be closed after starting were about an inch from the spark plugs on that thing. Got bit more times than I want to count.

That is the engine numbers, I would like to see the Ariens model and serial numbers l

TobyU said:

We have to be very careful how we say this. If a coil gets battery voltage, it is blown in shot in under a second!
What happens is the kill switch tab on the coil is grounded to the machine when the key is in the opposition but of course not when it's in the start or run position or at least that's the way it's supposed to be.
We don't want anyone to ever shoot 12 volts to a coil because it will likely damage it and quickly.
Flaky switches do this all the time. This problem is likely a messed up switch if no one has messed with the wiring.
EDIT: I just found what kind of engine we're talking about and it has a automotive style coil with a plus and minus apparently so that's why I was confused.
I was thinking traditional lawn mowers and not old school tractors. lol
Maybe that's why the old guys always called them magneto's.

Click to expand...

And just to throw in what might be considered useless info, most of the old guys I know call a magneto a magneto, a coil a coil and the newfangled thing you’re speaking of an ignition module. It is an item made up of different components all combined into a modular unit. And when mounted on an engine and coupled with the magnets of a flywheel those two components become a magneto. Same as an old push mower with points, condenser, flywheel with magnets and a coil. Those components combined also become a magneto.

mcostello said:

I just came up from starting the mower. I hooked up a live 12V wire and it turned over 2-3 times and started right up, which it has never done. So I bypassed the switch. Now I need to know which switch to buy. The Wife is very happy as this is Her mower.
Model 341S
Specs 71109A
serial 8318085

Click to expand...

Any chance you could post a picture of the terminal side of your current key switch. There are several switches you could make work but it could be nice to know what type of terminals your switch has and how each terminal is labeled. An Oregon switch part # 33-389 could be made to work but not match your plug exactly.

That is why I requested the units model and serial numbers. I want to know which switch originally came with the unit. Seems like the switch has been changed out a certain of times.

Ariens model 931018, serial 002307. Pictures of switch coming this evening.

The switch Veg. posted is the same one I found on the Ariens site. You need to look at the back of the switch and see if the terminals are labeled the same as those pictured. I’m posting another picture which may be easier to see.

Rivets said:

The switch Veg. posted is the same one I found on the Ariens site. You need to look at the back of the switch and see if the terminals are labeled the same as those pictured. I’m posting another picture which may be easier to see.

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Yeah I should have attached it differently. It cut off a bit of the picture in the thumbnail but if you click on it to open it, it should become a much better picture.

VegetiveSteam said:

And just to throw in what might be considered useless info, most of the old guys I know call a magneto a magneto, a coil a coil and the newfangled thing you’re speaking of an ignition module. It is an item made up of different components all combined into a modular unit. And when mounted on an engine and coupled with the magnets of a flywheel those two components become a magneto. Same as an old push mower with points, condenser, flywheel with magnets and a coil. Those components combined also become a magneto.

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Very true but that all becomes semantics at some point and that was about 20 years ago. Lol
Often when customers call me using terms I will say something along the line "coil, magneto, ignition module are all commonly used interchangeably"
It doesn't make it totally proper or accurate but when you're searching for parts especially on eBay and amazon, you will find them under all those headings and probably some more.

In this thread though, I didn't realize at first we were talking about an older k-series Kohler so I assumed we were talking about a magneto style ignition and not and automotive style tower like coil.

VegetiveSteam said:

Yeah I should have attached it differently. It cut off a bit of the picture in the thumbnail but if you click on it to open it, it should become a much better picture.

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You will find there are two commonly available switches like that.
They are even available at advance Auto Parts in a O'reilly Auto Parts and they carry them either out on the floor hanging up or in the back with their other lawn mower parts. One has an extra terminal on the outside edge so all you have to do is count the terminals and it should work for yours if you match it up.

TobyU said:

In this thread though, I didn't realize at first we were talking about an older k-series Kohler so I assumed we were talking about a magneto style ignition and not and automotive style tower like coil.

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What makes things worse is internal magneto, external magneto and battery auto style coil ignition were all used on those K series engines.

ILENGINE said:

What makes things worse is internal magneto, external magneto and battery auto style coil ignition were all used on those K series engines.

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Yep, and not to mention solid state breakerless.

Here is the switch that I have used since We have owned it.

Clean your switch up a bit and see if any of the terminals are labeled. If they are labeled the same as the pic I attached the Oregon 33-389 or Kohler 48 099 01-S are two that would be the same. The Oregon one is available on Amazon for around 20 bucks. Rivets also posted the part number for the OEM Airens switch which would be the same as the Oregon or Kohler switch. Just don't get a switch that has any terminal marked with an M. That would be the most common switch these days but won't work for your application.

Just a thought here. Before you blame the switch, would the engine keep running if you removed the jumper? It may not be the switch. I could be an issue with the wire between the I terminal on the switch and the + side of the coil. Remove the jumper and turn the key to the on position and see if you have battery voltage on the wire connected to the + terminal of the coil. Or turn the key to on and jump across the starter solenoid and see if the engine starts. If it does you know the power wire to the coil is good. Then get a new switch.

That tells me a lot and very little! First, you’ve done very little to identify which switch you have and because of that you have got this thread going in circles. I‘m wondering about your knowledge of how a basic electrical circuit works on a small engine? Have you read through the section in the manual which was posted, how a Kohler battery assisted ignition system works? Plus do you understand how it works? You’ve made a very common assumption that just because that is the switch in the time you’ve owned the unit. When dealing with electrical problems you “NEVER ASSUME ANYTHING AND DOUBLE CHECK EVERYTHING “. As stated clean that switch and identify each terminal. Waiting to hear what you find.

Five pages and getting no where.

Only commenting....Not trying to help or interfere Rivets.
But personally would I try reading the Ariens service manual electrical section.

Star, you and I could probably have solved this problem in an hour, but we know how to troubleshoot electrical problems. Too many cooks who don’t know how to boil water are confusing the thread and the OP has no idea how to troubleshoot. I’m probably going to leave this one unless the OP can show me he is at least one step above basic electrical circuit knowledge.

Rivets said:

Star, you and I could probably have solved this problem in an hour, but we know how to troubleshoot electrical problems. Too many cooks who don’t know how to boil water are confusing the thread and the OP has no idea how to troubleshoot. I’m probably going to leave this one unless the OP can show me he is at least one step above basic electrical circuit knowledge.

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Probably not that long. and most of the time would be spent rounding up tools and then researching and getting the items needed to effect the repair. The direction of the issue was solved on page 1 but still not much closer to an actual cause of the problem, being a key switch issue or something with the wiring.

That's basically it. With experience come knowledge of how to do things. Sometimes it is better to just let a professional do the work as he has done the investing his time and money in having whatever is needed to do the job. Beside it is a lot less frustrating but of course some think we are just gouging them.

Sorta like the time a customer decided he was a better tech than my lowly shop was. He spent over $400 and still had to bring the mower into the shop for me to spend 15 minutes and find a fifty cents terminal bad. But of course he wanted me to make whole again by buying his used parts.

I just pass the 47 yrs of electrical troubleshooting experience and yet there are times it takes some head starching due to some unusual wiring.

StarTech said:

Sorta like the time a customer decided he was a better tech than my lowly shop was. He spent over $400 and still had to bring the mower into the shop for me to spend 15 minutes and find a fifty cents terminal bad. But of course he wanted me to make whole again by buying his used parts.

I just pass the 47 yrs of electrical troubleshooting experience and yet there are times it takes some head starching due to some unusual wiring.

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Had a customer bring me a Briggs 5 hp in a box totally disassembled down to the bare block, because it wouldn't start and he couldn't determine why. I totally has to reassemble the engine to determine what the issue was. In the end found that it had a faulty spark plug.

And you are right about the wiring on some of these mowers. Some of the wiring on mowers make you say WHAT.

There are no letters visible on the back of the switch after I cleaned it up gently. I do not have a lot of small engine electrical experience. I have a small machine shop and weld, turn, bore and otherwise do metal repair. I have a lot to learn about small engines.I clean and rebuild carbs.
The terminal marked B goes to the amp gauge, gauge goes to left side of regulator. Terminal on top goes to top of regulator to ground. This is as far as I got. Will continue tomorrow. Will run down more wires tomorrow. I have battery voltage to the coil with the switch in the run position, no voltage to coil in start position, but the engine coasts when letting off on the key and starts when coasting.

Yes My electrical troubleshooting is weaker than I like, but I am learning. I had to go into town today and had to drive past O'reilly's twice. I decided to drop in and see what They had. I found the switch referred to above and it works. I thank Every one that has helped Me with this problem.

I’ll bet if you look carefully you will will find letters stamped on the metal terminals.

mcostello said:

Yes My electrical troubleshooting is weaker than I like, but I am learning. I had to go into town today and had to drive past O'reilly's twice. I decided to drop in and see what They had. I found the switch referred to above and it works. I thank Every one that has helped Me with this problem.

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Glad you got it.

No letters on terminals, letters on new switch are almost under the terminals, old switch is too old to see,new one just barely. Looks exactly the same. will check patent numbers shortly.

mcostello said:

Yes My electrical troubleshooting is weaker than I like, but I am learning. I had to go into town today and had to drive past O'reilly's twice. I decided to drop in and see what They had. I found the switch referred to above and it works. I thank Every one that has helped Me with this problem.

Click to expand...

Most peoples electrical troubleshooting skills are not what they would like. It takes times to get competent at it and I didn't say good. the thing with auto electric or small engine electric is sometimes you have to go slow to go fast. It has to be done step by step and follow the system, because you may miss something by jumping around.

I would say i am not the best. Part of my skills come from experience and mistakes along the way. If you are into watching Youtube look up Eric O with South Main Auto. This guy is probably the one of the best electrical auto troubleshooters on the web. This guy get the stuff that is towed in from the 3rd dealer and had several thousand dollars worth of parts thrown at them and they ask him to diagnose or repair them. And will show his system of diagnosing problems with vehicles. I would say he has probably doubled my working knowledge of how to troubleshoot issues. He for the most part doesn't work on small engines but what he shows when he goes through his techniques on cars and trucks will also apply to troubleshooting small engines.

Rivets said:

I’ll bet if you look carefully you will will find letters stamped on the metal terminals.

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Some have them on the terminals some are printed on the backing plate of the switch. there are a few out there that are unmarked. there is was period that one of the companies that I worked with sent out a bulletin saying the terminals on their keyswitches would be unmarked.

No patent numbers on new switch. Old key fits new switch. New key too big to fit old switch, filing will fit that, just for reference.
I took the old switch apart,because I am like that. and the switch was not burned out or anything. It was functioning as intended, just the wrong switch for the application. Thanks all, Mark.

mcostello said:

No patent numbers on new switch. Old key fits new switch. New key too big to fit old switch, filing will fit that, just for reference.
I took the old switch apart,because I am like that. and the switch was not burned out or anything. It was functioning as intended, just the wrong switch for the application. Thanks all, Mark.

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I kind of doubt that unless the mower has always agreed this way....I forget the previous discussion on that. Lol
Of course a switch should send power to that coil even in on position AND in cranking position.
Did you get a new switch that looks identical to the old?
If so.... It's 99.9% likely the same switch application and it will have power in on and cranking AND your old one should too!
I've seen several of these and similar do the same thing.
They don't make contact on cranking position sometimes just due to some corrosion or spring pressure being weak or the plate inside flexing.
Also seen them blow ignition modules due to slightly bridging 12v to kill switch term a you turn switch (usually to off) as it only takes a millisecond.

Everything works now. New switch identical, even the old key works.

mcostello said:

Everything works now. New switch identical, even the old key works.

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Then as I mentioned .... the old one wasn't functioning as intended.
It was losing a connection in the start position.