Onan Ignition Module testing - off the engine

[Jess 29]

If you are getting spark when this happens then the only other problem  must fuel. I am assuming that the air intake is not blocked. Check the gas cap. It has a vent hole and may b e clogged. This forces the fuel pump to pull against a vacuum. When it stops running pour about a spoon full of gas in the carb. I have a small fuel tank with a cutoff valve and two feet of hose. When I have a problem like that I hook it up and gravity feed it. If it starts then I hook it to the fuel pump and sit the tank down below it.     

 

If you are getting spark when this happens then the only other problem  must fuel. I am assuming that the air intake is not blocked. Check the gas cap. It has a vent hole and may b e clogged. This forces the fuel pump to pull against a vacuum. When it stops running pour about a spoon full of gas in the carb. I have a small fuel tank with a cutoff valve and two feet of hose. When I have a problem like that I hook it up and gravity feed it. If it starts then I hook it to the fuel pump and sit the tank down below it.     

 When it dies its almost like its running out of fuel , but I have the air filter off and I turn the key and crank it I can see fuel dripping into the carburetor ? It will not start again with out letting it sit? I assume if I'm seeing fuel drip that it is getting fuel and it smells like its flooded but no start ?

After I let it sit , it starts right up without chocking or giving it any throttle and it runs and sounds great . I will try dumping more gas in it tomorrow when it dies. I put a new clear fuel filter on it just before the carb and I see fuel in it when it dies also . When I had the ignition coil off it tested fine with my meter according to the Ohmage spec. I will check the gas cap also.  I have tried just about all that my mind can come up with ?

Thank you again for your response

[Jess 29]

If you are getting spark when this happens then the only other problem  must fuel. I am assuming that the air intake is not blocked. Check the gas cap. It has a vent hole and may b e clogged. This forces the fuel pump to pull against a vacuum. When it stops running pour about a spoon full of gas in the carb. I have a small fuel tank with a cutoff valve and two feet of hose. When I have a problem like that I hook it up and gravity feed it. If it starts then I hook it to the fuel pump and sit the tank down below it.     

 

 

Well I guess I spoke to soon! It ran great for about 20min when I was testing it out and the it started to loose power and backfire ! It died again. Back to one dead horse. It would not restart.

It was getting gas and spark. I let it sit for a while and then it started right up and ran great for about 15 min and died again. when it dies it wont restart with out letting it sit for about 20 min or so. I pulled the carb off and took it apart and cleaned everything and reinstalled it thinking maybe a float thing. It started right up again and ran great for about 5 min and back to the same thing?

Maybe electrical or some kind of timing thing? Maybe the ignition coil ?

 

 When it dies its almost like its running out of fuel , but I have the air filter off and I turn the key and crank it I can see fuel dripping into the carburetor ? It will not start again with out letting it sit? I assume if I'm seeing fuel drip that it is getting fuel and it smells like its flooded but no start ?

After I let it sit , it starts right up without chocking or giving it any throttle and it runs and sounds great . I will try dumping more gas in it tomorrow when it dies. I put a new clear fuel filter on it just before the carb and I see fuel in it when it dies also . When I had the ignition coil off it tested fine with my meter according to the Ohmage spec. I have tried just about all that my mind can come up with ?

Thank you again for your response

[Jess 29]

for some time now when I put the throttle up for high speed it moves back down slowly by it self? I hooked an extra spring up on the throttle lever to the screw on the dash to help it stay up and this has worked for a number of years now. Also when I had the air cleaner off I found a small ball bearing on the top of the engine? I see something about the fly balls ? I don’t know if this has anything to do with anything but thought I would let you know?

Edited September 29, 2014 by Jess

[Jess 29]

Well I went out this morning and it started right up and ran like a champ! So I mowed with it untill it died again . I made it into my garage and pulled the air filter off an it is getting gas. So I pulled a plug out and it was not getting spark like I thought!! It feelis like I keep going over the same thing over and over   NO SPARK ant that is where I started 4 months ago . I lieft it sit for about 15 min and I had spake again and it even tried to start with out the plug being in. I put the plug  back in and thats where Im at. Man when it runs it runs so good !  Feel at a los

Edited September 29, 2014 by Jess

[Jess 29]

Yes. I don't know (yet) which is the North or South pole on the rotor, but the on and off transition of the ignition module is triggered by a north pole and then again by a south pole.

So yes, just flip the magnet over end for end. A bar shaped magnet would be best and easiest to use.

Well I went out this morning and it started right up and ran like a champ! So I mowed with it untill it died again . I made it into my garage and pulled the air filter off an it is getting gas. So I pulled a plug out and it was not getting spark like I thought!! It feels like I keep going over the same thing over and over NO SPARK ant that is where I started 4 months ago (GroundHog Day ). I lieft it sit for about 15 min and I had spake again and it even tried to start with out the plug being in. I put the plug back in and thats where Im at. Man when it runs it runs so good ! Feel at a loss

Edited September 30, 2014 by Jess

[Jess 29]

A little time saver to confirm an Onan ignition module is functional prior to installing it, reassembling the engine and keeping your fingers crossed.

The diagram below shows how to wire up a standard tail lamp assembly and a few alligator clips to complete the testing. All the wiring and testing can be accomplished on the bench.

One Caution - DO NOT TOUCH THE BLACK MODULE LEAD TO 12 VOLT POWER AT ANY TIME. IF NO LOAD (lamp or ign coil) IS PRESENT IN THIS LEAD THE MODULE WILL BE DESTROYED.

The modules I have tested so far power have all powered up with the tail light on. When the trigger ring is rotated near the "nose" of the module, one of the two magnets embedded in the trigger ring will turn off the lamp and continued rotation of the ring will pass the second magnet over the "nose" and once again turn on the lamp.

An ignition coil puts about a 3 - 4 amp load on the ignition module. A standard automotive tail light will also put the module under approximately the same load and provide a good simulation of the ignition coil load.

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i think you are loosing 12+ volts to the coil when you operate the pto. check the wiring at the pto microswitches to make sure that is wired correctly, all terminals are making contact and the switches aren't damaged from the lever...... 

with it running, check the yellow wire at the coil (+) for 12 volts. operate the pto lever, check again. if you don't have 12v at the coil (+) when the lever is on while engine is running problem is in the pto wiring/switch or kill relay somewhere. if you can get enough access to the pto switches you can test them while the harness is still plugged in. the pto switch(es) work in a way that ignition power will be cut if the engine isn't running, so you can't start it with the pto engaged. but with the engine running you should be able to engage and disengage the pto without loosing power.

Well I went out this morning and it started right up and ran like a champ! So I mowed with it untill it died again . I made it into my garage and pulled the air filter off an it is getting gas. So I pulled a plug out and it was not getting spark like I thought!! It feels like I keep going over the same thing over and over NO SPARK ant that is where I started 4 months ago (GroundHog Day ). I lieft it sit for about 15 min and I had spake again and it even tried to start with out the plug being in. I put the plug back in and thats where Im at. Man when it runs it runs so good ! Feel at a loss

 

[Martin 2,132]

because you had an issue with wiring shorting before, from insulation on wire worn off, I'm going to suggest you go through absolutely EVERY INCH of the harness. there is a spot up near the upper steering shaft can/will rub on the harness and that would be my first area to look. you need to go through every connection as well, looking for corrosion or broken, missing terminals. 

 

i think you are at a stage now where you can't avoid inspecting the whole harness, i would even go so far as pulling parts to make it easier to get to everything, i.e. battery, engine, seat pan, hood stand covers etc.....

[Jess 29]

because you had an issue with wiring shorting before, from insulation on wire worn off, I'm going to suggest you go through absolutely EVERY INCH of the harness. there is a spot up near the upper steering shaft can/will rub on the harness and that would be my first area to look. you need to go through every connection as well, looking for corrosion or broken, missing terminals. 

 

i think you are at a stage now where you can't avoid inspecting the whole harness, i would even go so far as pulling parts to make it easier to get to everything, i.e. battery, engine, seat pan, hood stand covers etc.....

I did it. Pulled the pan , all covers hood , battery, seat switch , 2 PTO switches , light switch, test switch flywheel carburetor put in new key switch, starter solenoid , plugs, ignition module , condenser

 gas filter air filter . The only thing I did not do is pull the small black harness out that runs through the engine down to the starter and solenoid.  All wires are clear and look good .

Could there be a sensor or kill switch that is opening up when I run it for a while ?

Edited September 30, 2014 by Jess

[Martin 2,132]

But did you look at every bit of the harness? Both tractor and engine? The engine harness has a real tight spot where it passes under the intake and there is way too many areas on the tractor that could be suspect. How did you test the wiring to say it's good?

The fact that you are still having intermittent problems means there is still a problem waiting to be discovered. It's a lot of work to pull both harnesses and go over them in detail, but I feel it's your next step.

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[Jess 29]

But did you look at every bit of the harness? Both tractor and engine? The engine harness has a real tight spot where it passes under the intake and there is way too many areas on the tractor that could be suspect. How did you test the wiring to say it's good?

The fact that you are still having intermittent problems means there is still a problem waiting to be discovered. It's a lot of work to pull both harnesses and go over them in detail, but I feel it's your next step.

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I checked all the wires for breaks and contact points. I don’t see this as an intermittent problem? It happens the same way every time I start and run it. I start it and it starts right up then weather I drive it or let it sit while it's running it will shut down after approximately 10 minuets and loose spark. I let it sit for aprox 15 min and it regains spark and will start right back up again . But now that it is hot it shuts down in a les amount of time. I will pull the harness out of the tight spot in the engine block and check it as best I can. I look for breaks in insulation and check it with my meter for continuity . I don’t know if I will be able to put it back in there? It is very tight, but I can move it a bit back and forth .

What else can I do except start replacing wires? Could the coil be heating up as I have read in some other post and be the culprit ? I have read that there is a coil that I can purchase for around $40 ? Where can I buy this and what do I look for?

Thank you for your time and help

Jesse

Edited September 30, 2014 by Jess

[km3h 543]

You have e spent a lot of time on this tractor with no rewards. You said it was getting spark when it stopped running and then you said it wasn't getting spark. Get yourself a jumper wire. Go out and run the tractor until it stops running. Try to restart it. If it won't restart, place the jumper wire from the positive side of the battery to the positive side of the coil and try to start it. If it starts, replace the ignition switch. Don't clean it and don't fool around with it, just replace it. Make sure you get the proper switch for your tractor. They all look alike but internally they are different. By the way, have you checked the condenser? Is it fastened tightly.

 

How many hours on this machine? Many times simply cleaning dirty, corroded connectors is not enough. they can be corroded inside the pin where they are crimped.  

Edited September 30, 2014 by km3h

[Martin 2,132]

Have you tested the coil immediately when it cuts out? Ohm the primary and secondary terminals. Also check to see if you lose 12v to the coil the moment it cuts out.

You are just going to have to check and test the moment it cuts out.

Also, do you know it's ignition related and not fuel ? definitely missing spark when it stops? Just because it has fuel in the carb don't rule out that unless you pull the top off the carb and check the fuel bowl.

These issues are so hard to remote diagnose , if you have somebody else looking at it they might see something you are missing. But we are only going on what you post. Could you do a video of it running and when it cuts out? It might just help somebody here steer you in the right direction.

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Edited September 30, 2014 by Martin

[Jess 29]

You have e spent a lot of time on this tractor with no rewards. You said it was getting spark when it stopped running and then you said it wasn't getting spark. Get yourself a jumper wire. Go out and run the tractor until it stops running. Try to restart it. If it won't restart, place the jumper wire from the positive side of the battery to the positive side of the coil and try to start it. If it starts, replace the ignition switch. Don't clean it and don't fool around with it, just replace it. Make sure you get the proper switch for your tractor. They all look alike but internally they are different. By the way, have you checked the condenser? Is it fastened tightly.

 

How many hours on this machine? Many times simply cleaning dirty, corroded connectors is not enough. they can be corroded inside the pin where they are crimped.  

There is around 1,300 hrs on it . In my previous reply I mentioned among other things that I did replace the ignition switch with a brand new Toro key switch and I checked it to make sure it was exactly the same before I installed it . I also installed a new onan condenser I ordered from Toro I also replaced the starter solenoid as it was acting up.

I have spent countless days and hours on this machine ! I have had it for so many years and feel like its part of the family (HA) My son has tried to get it off me many times! It has always been a great machine and other then regular maintenance has never given me much trouble until now! For some reason years ago It would not run right unless I added some fuel stabilizer to the fuel. I don’t know if it was when they started adding stuff to the gas or what, But always ran great other then that. But one time after I relocated here to Missouri I decided to drive 60 miles and take it to the only Toro dealer/ mechanic in the area to check it out and have it serviced! When I brought it home it started backfiring and doing all kinds of stuff!. It never did it before he touched it. So I brought it back to him and it really has never ran the same way it use to after that.

My bad! I never took it to him again!

Yesterday when it stopped I pored a bit of fuel in it as you had recommended and it still would not start. I immediately pulled a spark plug out and had no spark at all. I went out 20 min later and it had spark and I put the plug back in and it fired right up and ran great. I shut it down and that's where I left it.

I stepped away from it today to clean my garage and straighten out my tools so I can find them the next time I need them. I did not touch it at all today. I wanted to but left it and me alone !

 I wil run it tomorrow and when it stops I will put a jumper on and see if it starts. I would post a video but I dont think I can get it to upload. I could do it on Face Book as it will load there but does Red Square have a F/B account?

   Thank you all for your time and help

   Jesse

[Martin 2,132]

youtube is the best way to do a video. just copy and paste the link for sharing. put the link straight in the body of your post, don't use the link icon or any other icon in the header above the posting area.

[km3h 543]

When it stops running, is there 12 volts from the battery ground to the positive side of the coil, with the key on. Did you try running a jumper from the positive side of the battery directly to the plus side of the coil when it would not start. I believe you are losing voltage to the coil intermittently.

 

A good father like would never give his son a broken 520. So I suggest you strap it to a pallet and ship it to me.

[Jess 29]

When it stops running, is there 12 volts from the battery ground to the positive side of the coil, with the key on. Did you try running a jumper from the positive side of the battery directly to the plus side of the coil when it would not start. I believe you are losing voltage to the coil intermittently.

 

A good father like would never give his son a broken 520. So I suggest you strap it to a pallet and ship it to me.

My 520H is good now its my 518 H  (No One wants a 518

[Jess 29]

My 520H is good now its my 518 H  (No One wants a 518

 

My 520H is good now its my 518 H  (No One wants a 518

ran it for a while this morning! It always starts right up and runs great for about the first 10 minuets or so. It starts breaking up before it dies , like its running out of fuel that was the reason I took the carburetor off and completely tore it down and cleaned it . I ran a jumper form the battery plus side to the coil plus side but it did no good. It sill died. I left it out in the yard and went back after a while and it fired right back up and ran great. I pulled it into the garage and just let it sit and run after about 20 min it started breaking up again and died. I ran about a half a tank of fuel through it this morning . Its was weird as it was dyeing I put the PTO on and off and it would straighten out for a while but it still died.

I left it and didn’t mess with it any further today . My son went out and bought one of those throw away Huskie mowers from Lowes !

Edited October 2, 2014 by Jess

[Save Old Iron 1,566]

I'm thinking the one variable here we haven't considered yet is heat. Engine takes 20 minutes to heat up under forced air ventilation after sitting all night - this is fairly repeatable. Also cools down in 20 and then restarts - repeatably. I'm thinking dirt in the carb is probably not that repeatable - nor is vacuum developed in the gas tank.

 

I suggest either the ignition module or the ignition coil is temperature sensitive.

 

I have not tried this suggestion but if you could place a .5 to 1 ohm high watt resistor in series with the ignition coil + lead, you will run the ignition system on 9 - 10 volts. This will limit the heat buildup in the coil. The ignition module will still get heated from the engine block.

 

If the tractor runs 20 minutes with the resistor and quits, I might suspect the ignition module. If it runs longer than that, I would think the coil was overheating.

 

Of course you could just grab a test light and when the engine quits, clip the test light cord to battery POSITIVE and probe the negative ignition coil post - crank the tractor - if the light flashes, the ignition module is sinking current thru the test lamp and should flash. If it doesn't flash, suspect the module. If it does flash, suspect the coil.

[Save Old Iron 1,566]

consider the electronic ignition module lives in a high heat environment - electronics don't like heat

 

consider the ignition coil lives in a high heat and high vibration environment - the coil is just that - a coil of copper wires with an extremely thin coating of enamel paint as insulation. Vibration of the wires can crack off the insulation and heat can expand the copper wires to the point where chaffed wires touch each other and (temporarily) short out and disable the function of the coil.

[Jess 29]

consider the electronic ignition module lives in a high heat environment - electronics don't like heat

 

consider the ignition coil lives in a high heat and high vibration environment - the coil is just that - a coil of copper wires with an extremely thin coating of enamel paint as insulation. Vibration of the wires can crack off the insulation and heat can expand the copper wires to the point where chaffed wires touch each other and (temporarily) short out and disable the function of the coil.

 

consider the electronic ignition module lives in a high heat environment - electronics don't like heat

 

consider the ignition coil lives in a high heat and high vibration environment - the coil is just that - a coil of copper wires with an extremely thin coating of enamel paint as insulation. Vibration of the wires can crack off the insulation and heat can expand the copper wires to the point where chaffed wires touch each other and (temporarily) short out and disable the function of the coil.

I pulled the fly wheel and replaced the ignition module last week. That is why I'm thinking the coil may be bad and breaking down? I read on another post that I can by a similar replacement coil for around $40 ? Do you know where and what I am looking for  ? It would be worth putting some more $ into it after all the work I have done on it . Whe I started this I pulled the coil out of my 520H should I do that again and see if that is the problem ? But if I can buy one on the cheap $40 aprox , it would be worth it .

   Thank you for your time

Edited October 2, 2014 by Jess

[Save Old Iron 1,566]

put "harley coil" in the search box - make sure to select FORUMS option.

 

there are several threads on low cost replacement coils.

Edited October 2, 2014 by Save Old Iron

[Jess 29]

put "harley coil" in the search box - make sure to select FORUMS option.

 

there are several threads on low cost replacement coils.

I found several different Harley coils ? which one should I purchase ? Harley Ignition Coil 3 Ohm single fire ?

 I see 3 OHM 5 Hom single fire, double fire ext,

Edited October 2, 2014 by Jess

[Martin 2,132]

 

I found several different Harley coils ? which one should I purchase ? Harley Ignition Coil 3 Ohm single fire ?

 I see 3 OHM 5 Hom single fire, double fire ext,

 

 

since the oem coil primary resistance should read somewhere around 2.9-3.6 ohms,  you would need a 3 ohm coil, heres one post that comes up when you search 'harley coil" as soi mentioned.......

 

Edited October 2, 2014 by Martin

[Jess 29]

since the oem coil primary resistance should read somewhere around 2.9-3.6 ohms,  you would need a 3 ohm coil, heres one post that comes up when you search 'harley coil" as soi mentioned.......

 

What do they mean ny single fire or double fire ?

[Martin 2,132]

What do they mean ny single fire or double fire ?

 

 

dual fire (called batch fire, waste spark also) fires both cylinders at the same time....

this is similar to the Onan setup, the ignition module is your switching device.....

one cylinder is needing the spark, one is on exhaust, then the opposite when the other cylinder needs it.

note only one switching device

 

 

single fire only fires each cylinder when needed.....

note, two switching devices

 

Edited October 2, 2014 by Martin