Kohler running on one cylinder

[greasemonkeyok]

Having enough current to create a visible spark in the open air is not the same thing as having enough current to create a spark that will ignite the fuel mixture under compression. Two factors are key to igniting the fuel mixture, sufficient compression and sufficient spark. Since your compression is good, that leaves a lack of current as the likely culprit - but then you already know that.

 

[_RaT_]

Having enough current to create a visible spark in the open air is not the same thing as having enough current to create a spark that will ignite the fuel mixture under compression. Two factors are key to igniting the fuel mixture, sufficient compression and sufficient spark. Since your compression is good, that leaves a lack of current as the likely culprit - but then you already know that.

As an electrician, I had to think about this. Having sufficient voltage might really be the issue. While one generates very little current when walking on a carpet, they can generate a considerable voltage and produce a visible spark when touching anything that will take those excess electrons like a switch screw or another person. I'm trying to apply this kind of idea to a coil and the resulting collapsing magnetic field that produces the very high voltage from 12V. If there is a bad coil be it from a loss of insulation thus having fewer windings to create as much voltage from the 12V source then it would be a voltage issue I would think that the current while there is quickly grounded out through the shorter path. Just thinking out loud.

 

[greasemonkeyok]

Being an electrician, you know more than I. My understanding is, voltage determines how large a gap the spark will jump, and the current determines how much energy (heat) that spark releases. So, and this is a question not applicable to a magneto, the coil determines the voltage and the capacitor determines the current?

 

[Jim Thompson]

The coil is actually a transformer and the output voltage is a function of input voltage and the ratio of primary vs secondary windings. the function of the condenser/ capacitor is to prevent the points from arcing when they open.

I suppose that if one were curious enough, one could calculate the current through the coil's secondary but it would require more effort than I'm willing to expend.

 

[jdgreg]

Whether it was the coil, or the spark module, I dont care cause it runs like a champ now! :thumbsup: :thumbsup:

Replaced both the coil and the module, adjusted the air gap on the new and old coil, bolted it all back together and she started right up!! Biggest PITA was getting the driveshaft yoke lined up and back onto the hydro pump shaft. MAN :confused2:

Anyway, thanks all for the suggestions and support.

 

[Tennessee 8n]

how much did those parts cost?

 

[juke46box]

I've searched and read several threads here of similar issue as mine, and it sounds like my problem might be an ignition coil. I have a Simplicity Legacy mower with a Kohler 25. I was mowing on a slope when it started running very weak. I looked at the fuel gauge, and though I had about 1/2 tank, the slope was to the right, so the gauge was on E. I figured the fuel pickup was not getting ample fuel supply.

So I disengaged the mower, and eased it onto level ground, and worked the choke a little, which had no effect on it. Made it back to the garage, barely. I cleaned off the foam pre-screen, checked the plugs, checked the harness connector on the right side, all looked ok.

I narrowed it down to running on one cylinder, as I could pull the right spark plug wire off, and it had no effect. When I pulled the left, it would stop running. I swapped plugs to make sure it wasnt a bad plug, but the problem did not follow the sparkplug.

I connected an old Sears timing strobe light to each plug wire as it was running, and both sides made the timing light come on the same brightness.

I dont think it is fuel related. I filled up the tank, and ran it (on one cyl) for a few moments, no change. If the carb had clogged passages, choking it would have a more positive effect on how it runs, and both cylinders would be running, even somewhat intermittently. Now, only the left cyl is running.

Suggestions?

I recently rebuilt my kt17 2 and after the rebuild it ran great new pistons,rings,rods seals,gaskets,etc. Skip ahead to 7/28/17 the engine started runing on one cylinder the left one. both cylinders had fire but not very good fire . Long story short the points had worn and closed to a gap of about 03 thousands. instead of .20. after this both cylinders fired and ran like a top.this engine was meticulasly rebuilt by me and the kohler factory manual. It has aprox 95 psi comp.I sure hope this helps clear the air on this problem.