No spark diagnosis help please

Reply

  #1  
Old 07-08-06, 03:05 PM
Member
Thread Starter
Join Date: Mar 2003
Location: Delaware Co, NY
Posts: 173
Unhappy No spark diagnosis help please

I have a 30+ year old Jacobsen 1200 gear tractor with a 12hp Kohler engine, K301AQS, SPEC 47606D that is not getting spark. The points are good, correctly adjusted and appear to be functioning properly. It is getting gas. There is 12V to the positive side of the coil. When I ground the plug and crank there is no spark across the gap. It certainly could be the coil as the symptoms were intermittent and seemed to be heat related, until the point when it would no longer fire at all. I have, in fact, replaced the coil at least twice over the years.

My question is, could it be the condensor, or the voltage regulator? It has a solid-state rectifier-regulator. How could I test either of these components to determine if one of them are the cause before I buy a coil that I can't return if it's not the problem?

Thanks for any help you can provide.
 
Sponsored Links
  #2  
Old 07-08-06, 03:24 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,659
If your points are good and the condenser was put in at the same time, it's likely not the condenser. The voltage regulator shouldn't have anything to do with it.

I would say if all connections are good, based on what you described, it would be the coil. When you have/had it started and it began acting up, I imagine the coil would have been very hot to the touch.

If you're going through coils a good chance is you have an application that calls for an internal resistor in the coil. You say you have 12v at the coil which means you don't have the external resistor. The internal resistor would reduce the inflow voltage. Without it the 12v all the time would burn up your coil.

Hope this helps
 

Last edited by marbobj; 07-08-06 at 08:32 PM.
  #3  
Old 07-08-06, 04:14 PM
hopkinsr2's Avatar
Member
Join Date: Feb 2005
Location: canada
Posts: 1,561
If you have 12 volts @ the coil, Check it with a test light on the positive side of the coil. Now move the test light to the negative side (the side going to the points) & crank the engine. If the test light flashes, you need a coil, If the test light stays on, the points aren't closing. If it does'nt come on, the condenser is shorted, or the points aren't opening.Test like this & let us know the results..
 
  #4  
Old 07-09-06, 12:11 AM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,575
A very easy way to test the coil is to remove the plug, put it in the wire and lay it on the head of the engine so that the metal of the plug is touching metal on the engine. Turn the key on so that you have voltage at the coil. Remove the wires from the negative side of the coil, and connect a wire to a bolt on the frame or engine (ground it). Touch the other end of this wire to the negative side of the coil, and then remove it while watching the spark plug. If the plug sparks, the coil is good and I'd have a closer look at the points and condenser. If it doesn't spark, the coil is bad.

By doing this test, you are eliminating everything from the ignition circuit other than the coil. By touching the wire to the negative side and removing it, you are acting as the points.
 
  #5  
Old 07-09-06, 04:28 PM
Member
Thread Starter
Join Date: Mar 2003
Location: Delaware Co, NY
Posts: 173
Talking

So, I followed Cheese's advice and checked the coil as outlined. No spark. I'll buy new coil. I went to the Kohler website and followed their supersession sequence and now have the current part # and price.

As a result of my success, sort of, I became so ambitious that I broke out my ancient third-hand Lawn-Boy push mower, which hadn't been used in several years but nevertheless started right up, and mowed till I thought I would have a heart attack in this heat.

Still feeling ambitious, I then dragged out the 40+ year old Jacobsen riding mower, which had run a couple of years ago and also has no spark. I pulled out the points and condensor and will replace them. The points are in pretty rough shape and if I'm lucky that will be the only problem. It has a pretty standard old Tecumseh H-60 series engine.

I'll get parts tomorrow and hopefully have both riding mowers back in business.

If not, there's always the Lawn-Boy.

Thanks for the help!!
 
  #6  
Old 07-13-06, 09:28 AM
Member
Join Date: Jul 2006
Posts: 4
Will the Cheese test work for mine?

If I can, I would like to take this discussion a little farther for my benefit.

I have a less then 2 year old Poulan (271490) tractor with a Briggs and Stratton 14.5HP engine model 287707-1259. A month ago I had to replace the solinoid. Last week solinoid #2 went bad and in addition to that, I am now not getting good spark (either no spark or very weak).

I have replaced both the solinoid and the coil/armature/magneto? (the different systems and lingo confuse me, it is a square horseshoe with a small puck at the center and 1 tab for a ground) and still weak/no spark. I gapped the mag with the business card method so I think it is good.

I have checked all the grounds (except for the black wire that goes under the flywheel (to the alternator?) and seem to have good contact to the frame and continuity at the removable ground locations when I terminate to the battery.
Any suggestions on how I should proceed. Will the test method 'cheese described work for me too?

This is my first go around with electrical stuff. I have a meter but am not the best at using it.

Also, if you bored........how do these things work?
 
  #7  
Old 07-13-06, 09:42 AM
Member
Join Date: Jul 2006
Posts: 4
I have been reading thru old forums to try and see if this has already been discussed. In the course of that, I wanted to add that I did put in a new spark plug but did not check the gap before installing it. How critical is that?

Thank you.
 
  #8  
Old 07-13-06, 10:25 AM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,575
The test procedure above won't work on yours stoney. Your setup is a bit more modern, and works with solid state circuitry. On yours, unplug the small kill wire from the coil, and using a known-to-be-good plug, check for spark again. To check spark, make sure the plug is touching metal on the engine. Watch carefully, it might be a bit hard to see in the bright sunlight. If you have spark, there is a problem in the kill circuit on the mower. If you don't, either the coil is bad, or the coil wire is chaffed or pinched and grounding. The plug gap should be .030". Usually the gap they come set at is good, but sometimes the gap is closed. I think that happens when a box of plugs gets dropped. It bends the electrode shut. The plug should be a champion RC12YC, or equivalent.
 
  #9  
Old 07-13-06, 01:14 PM
Member
Join Date: Jul 2006
Posts: 4
Thank you. I will try this. From what I remember, I do not recall seeing a wire for the coil, only the ground wire that plugs into the blade. Where would I find this?
 
  #10  
Old 07-13-06, 08:00 PM
hopkinsr2's Avatar
Member
Join Date: Feb 2005
Location: canada
Posts: 1,561
That wire that plugs onto the blade terminal of your coil is the kill circit. Disconnect it & check for spark again. If there is spark, a safety switch may be bad, or if no spark, a coil assembly
 
  #11  
Old 07-14-06, 07:36 AM
Member
Join Date: Jul 2006
Posts: 4
Thank you guys. I am up and running!
 
Reply


Thread Tools
Search this Thread
Display Modes
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 12:05 AM.