K321s no spark

[Rubix 1]

My '84 314-8 K321s had been running very weak under load and eventually shutting off after an hour of mowing.

 

I replaced the coil, condenser, plug, and plug wire and it still ran the same way. I decided at that point I probably need to replace the carb, but in the meantime I then replaced the points since I had new sitting there from the isavetractors ignition kit. I figured it wouldn't hurt. Now I've got no spark. The points appear to be opening and closing properly, I rubbed the points with paper, and I've gapped them properly. 

 

I noticed the volt gauge on the instrument panel is not working when the key is in run or start. It's always worked. Do these go bad and interrupt the circuit and cause a no start? I hear the hour meter clicking as normal when ignition is in run or start, but could the ignition switch be bad, despite that the engine turns over fine?

 

Go figure my multimeter is dead when I need it, but I wanted to post and ask until I buy a new one tomorrow. Thanks in advance for your knowledge. 

 

Edited July 13, 2023 by Rubix
Added description

[ineedanother 1,369]

Hey @Rubix, lots to sift through here but it's possible that you're chasing the wrong rabbit. Don't be distracted by the voltmeter right now IMO. I would be interested to know what the fuel supply is to your carb when it dies. Your fuel cap might not be venting adequately, and at the age of your machine it would be prudent to replace everything from the tank to the carb. Fuel cockpit at the tank, fuel line (from NAPA or other reputable source), filter, and back-flow valve if you buy into that school of thought. 

 

I don't condone throwing parts at things but if you haven't done this, it's overdue and needs to be done regardless. I think your voltmeter issue is just distracting you from the performance issue.  

[ineedanother 1,369]

...and no spark is NOT a no-issue so I didn't intend to ignore that. You need to check all of your grounds and re-do them as needed. Check the block to battery ground, ignition to frame, points to block, etc.

 

The ignition switch to frame ground is somewhat infamous for being poor. It usually attaches to the tower beside the battery and depending on other grounds, might have to eventually travel down the tower through the frame and to the block (points). Lots of chance to fail so check all of those.

[Achto 27,588]

41 minutes ago, Rubix said:

I then replaced the points since I had new sitting there from the isavetractors ignition kit. I figured it wouldn't hurt. Now I've got no spark.

 

When in doubt, go back to the last thing that you did. Clean the points again with some 400grit or finer sand paper, then run some paper through them again. 

 

Just as a side note, I try to use the original points as long as I can. New points, OEM or after market are not as good as the older points were.

[8ntruck 7,007]

Isn't there a safety switch somewhere in the power supply to the points on that tractor?  The seat switch maybe?

[gwest_ca-(File Mod) 11,046]

314-8 is newer than 1984. Have a model number and serial number?

[Rubix 1]

I appreciate the responses thus far. 

 

@ineedanother I agree that my weak under load is likely fuel, I'm thinking the float in the carb. The cap is old but has a small crack in the top so I know it's venting. The lines are ok as I replaced one two years ago. The inline filter is clean and clear and new. I'm leaning toward the float, but I'll dive into that after fixing the no spark. 

 

Multimeter is telling me I'm not getting power at the coil. So, bad ground? Bad ignition switch? @Achto I'll look into that, I didn't realize that was a common failure. 

 

@8ntruck I have bypassed all safety switches as they failed over the years. It is worth double checking all those connections I made, maybe one has come undone. 

 

@gwest_ca 2114k801 , 1985? My mistake on the typo.

 

 

Edited July 13, 2023 by Rubix

[Rubix 1]

Well my ignition switch passes continuity testing. 

 

With the multimeter positive test lead on the positive coil terminal and the ground test lead on the ground battery terminal it reads proper voltage. With the ground test lead moved to the ground coil terminal I read no voltage. So that's a bad ground somewhere in that circuit, yes? 

 

The wire from the points to the coil passes continuity test. The coil itself passes continuity test. 

 

What am I missing here? Bad points? Condenser not grounding?

Edited July 13, 2023 by Rubix

[wallfish 17,000]

New points have a coating applied to them so they don't oxidize in the package. All new points need the contact surfaces cleaned to remove that coating. Then set points. 

You won't see anything to the - side of the coil if the points' contacts aren't connecting or the points are open

[Achto 27,588]

11 hours ago, Rubix said:

With the ground test lead moved to the ground coil terminal I read no voltage. So that's a bad ground somewhere in that circuit, yes?

 

As you turn the engine over your voltage should go on & off as the points open & close. Should read voltage across the coil terminals when the points are closed, no voltage when the points are open.

 

Your points actually provide the ground for your coil. Points closed the DC voltage builds up in the coil, points open the stored voltage is released to the spark plug. If you do not have voltage across the + & - on the coil when the points are closed, then you need to clean your points better.

Edited July 14, 2023 by Achto

[Wheel-N-It 2,969]

2 hours ago, Rubix said:

What am I missing here? Bad points? Condenser not grounding?

 I think you should look at the condenser, and the ground path back from the condenser to the frame of the tractor. If your coil is good, then a weak spark can be traced to the ground. 

It would be helpful if you would post some pics of the tractor and the engine, both sides of the engine and the front  of the engine, so we know what we are working with here. I want to rule out that somehow you have a shaker plate engine installed in your wheel horse.

[Rubix 1]

Great input from all, thank you everyone. 

 

Hopefully this thread will come up on the search feature in the future for no spark hunters. I did not find what I needed before I posted. 

 

Turns out it was the coating on the new points. I originally used paper per the instructions to no avail. After comments on this thread I used some 400 grit and voila. Mows great, hopefully for decades more. Thanks again. 

 

Edited July 24, 2023 by Rubix

[wallfish 17,000]

29 minutes ago, Rubix said:

Hopefully this thread will come up on the search feature in the future for no spark hunters.

Yup

And something to add. For battery ignition, if you turn the engine so the points are closed, put the key in the run position, you can manually flip the points open with a small screwdriver and look for spark. You can typically see it right at the points but it'll fire the plug too. Kinda check'm both at the same time.

[Handy Don 12,232]

19 minutes ago, wallfish said:

Yup

And something to add. For battery ignition, if you turn the engine so the points are closed, put the key in the run position, you can manually flip the points open with a small screwdriver and look for spark. You can typically see it right at the points but it'll fire the plug too. Kinda check'm both at the same time.

Sneaky. Veeerrry sneaky!