1250 no spark
 

Alright, so I tried to do my due diligence here but I still have a question after doing research and troubleshooting.

I read this thread to help troubleshoot since it seemed to be a similar problem and is the same model:

https://www.onlycubcadets.net/forum/...ad.php?t=44422

I followed J-Mech's suggestion of using a test light to ground and then attaching it to the - side of the coil while cranking the engine. This produced no flashing, and I double checked it with a multimeter as well. So following his logic, it could be the points, the wire to the points from the coil, a bad coil, or the unlikely problem of a condenser.

I double checked the wire from the points to the coil, removed it, inspected it and it looks good and continuity with a multi-meter passes fine. I checked continuity with it installed as well and it was good.

I replaced the condenser since I was able to find one locally for $8 and said what the heck. No changes.

I tested the coil using the method found here under the tech library:

https://www.onlycubcadets.net/forum/showthread.php?t=27

And it tested good. I was convinced it was the coil regardless because I saw a weird reading once or twice, so I brought it over my neighbor's (who has a 1976 John Deere 316) and swapped my coil onto his tractor and it started and ran as normal.

So that leaves the points -- I have a question, though. With the key ignition on, if I separate the points with a screwdriver slightly shouldn't there be a spark? I am getting zero life at the points. I did file them and checked timing -- it all looks good, but there's no power there whatsoever.

Anyone have an idea of what I'm missing here...? Driving myself nuts and it can't be that complicated I'd think. I checked the manual but it doesn't seem to have troubleshooting for electrical issues that I could see.

This maybe an odd question, but do you have reliable loadable power to the "+" side of the coil? (I didn't see this mentioned anywhere in you post)

As R Bedell has stated make sure your grounds are good too. nothing is more frustrating when chasing a power problem and it's only a bad ground.

Yes you should get a spark when you separate the points with the ignition switch on.

So it's reading .1-.2, so bad ground somewhere? I'm currently bypassing the PTO and Clutch/Brake safety switch to troubleshoot, so does that eliminate them out or is there a way to isolate things?

Yes, I am getting 12v to the + side of the coil when the ignition is turned on.

Then check the negative post of the coil with the ignition on.
If the points are open, you should see 12 volts,
if the points are closed you will see zero volts.
If the points are open and you see zero volts,
there is someting wong with your points (since you know the coil is good)

With your voltmeter set on ohms, key off, hook one lead to the - side of the coil and the other to one of the points mounting screws. With the points closed the meter should show.1 to .2 on the meter, lift the movable part of the points away and you should see infinity. It sounds like a classic case of crud across the contacts that you can’t see. Get a tiny flat screwdriver and scrape both sides until you see continuity. Put everything back together and enjoy

Sorry, took me a few days to get time to get back to this...just tried running a jumper wire from battery negative terminal to the points, key on, still nothing when I open the points gently with a flathead. Can points themselves go bad? Or am I missing something else here?

I suggest starting right at the switch.

I have voltage there to the coil with the key on, so I think that is okay?

Where on the points did you connect the jumper wire to? If you went on the screw terminal, this test tells you nothing.

This problem is a simple matter of battery and ground, and is one of them missing. There is no reason for this to be so difficult.

The simplest thing you have to do is disconnect completely the wire from the negative side of the coil, that is, the wire going to the points.
Put a meter or a light on the lug of the coil where you took the wire off.
Turn the key on and off. If the light or meter shows 12 volts working with the key then your good from the key switch. If not, your coil could be bad or pursue the trouble towards the switch.

If the trouble is not coming from the switch or the coil,.....
Then set your meter to ohms and connect one lead to ground on the engine block and the other lead to the end of the wire that you took off of the coil.
When the points are closed you will see continuity to ground.
Rotate the engine by hand until the points open and you should lose the continuity to ground.
If you do not lose continuity when the points open, the points are shorted.....replace them.
If you do not see any continuity when the points are closedl, the points are not making contact when they close, clean the contacts or better yet replace them.

I put it on the screw that holds the points on the engine plate.

Story of my life.

Sorry, maybe this is the problem -- I just want to clarify...

When the key switch is on, I have 12v to the + positive side of the coil (not the one going to the points).

On the negative side of the coil there is no voltage with just the key switch on. I thought there should not be 12v there until the engine turns over?

Just want to double check as you specifically bolded the negative side.

If the wire to the points (neg side of coil) is disconnected, you should see 12 volts on both sides of the coil..

Nothing with the condenser and the points disconnected either. Would that mean the coil is culprit?

I originally thought that but went and brought it over my neighbor's and his ran with mine hooked up and his disconnected so I'm a bit at a loss. I did not bring his up to my house and try it on mine, but figured I would not need to.

Just to clarify....
When everything is working as it should, the points open and close 1/2 the rate of engine rpm
When the points close (make contact), it allows current to flow thru the coil by providing a path to ground, thereby causing spark at the plug.
When the points make contact, you cannot see voltage on the coil because it is essentially grounded.

Points can cause problems like:
No ground is ever given to the coil because the contacts are dirty or pitted or gapped too wide
Ground to the coil is constant because the contacts are pitted and stuck together, or not enough gap.

Another possibility is a bad condenser. The condenser is a capacitor, in circuit, across the point ccintacts meant to keep the voltage constant and prevent arcing.

I did buy and replace the condenser during this troubleshooting and it did not seem to change anything.

I am leaning towards the coil if you are saying with the points and condenser disconnected there should be 12v on the - side.

I'll see if I can snag my neighbors to make sure.

Thank you for the clarification.

Thank you everyone -- it was the coil it seems. Happy 4th of July!!

I have a few questions since I had tried it on my neighbors and it started and ran -- though I didn't run it for more than a few seconds.

Can a coil go bad slowly? I would run it and it would turn off randomly, I'd go back to it later and it would start back up and run for a while (sometimes the whole time I used it) fine.

Yep my 1450 coil did some weird thing over a year. First after starting and running 5 minutes it acted like I was running out of fuel then came back up and was fine for the hour cutting grass. It never died completely I cleaned the fuel system etc... that appeared to make it go away. Then it would miss a little so I changed the plug that appeared to make it go away for sometime (I was not expecting the coil to be bad since it was only 4 years old) Then in the winter it starting back firing. I decided just to change the coil again, never had the issues again for over 2 years now. It was just weird.

Is that an internal resistor coil? Or non resistor coil? Sorry if this was already asked,

That looks like a Standard Motor "blue streak" external resistor coil....

Glad for you, congrats for your perseverance.

Yes, coils can be intermittent as they get old, especially if someone has left the key in the on position for any length of time without the motor running.
When that happens, if the points happen to be closed, excessive current is drawn through the coil and it overheats. It may continue to work, but the insulation between the thin wires inside has been deteriorated and it will never get better, only worse. You can see coils that have been overheated and are the tin casing is all bulged out but they continues to work, so who knows?

One other thing to add about the condenser.....
Make sure the clamp, where it mounts to the coil bracket makes a good clean metal contact, and also, the pig tail wire MUST connect to the NEG coil terminal (with the wire to the points).

Edit to add clarification about Cooperino's questionj about coil resistor....
Most vehicles using coils reduce the current flow thru them with a resistor. In the old days, they mounted a big resistor right there on the coil bracket.
Nowdays they build it internally into the coil. Most of the time the coil is marked as to what it is. You want one with internal resistor.