Kt-19 twin -explanation of dual spark setup

[tractorbeast 27]

Anyone have a good article of how the twin cylinder setup works. Since it has two plugs, how is the spark split-up and properly timed. Only one signal from the stator I am assuming? I have a twin with no spark. It started twice this year, but not the last time I tried. Coil ohms are correct. 12 volts to + side of coil is correct. Whats the easiest way to check the spark from the stator at the points??? That is the question! Thanks, steve

[Martin 2,133]

the kt uses whats known as waste spark ignition. both cylinders fire at the same time, one on the compression stroke at the same time as the other on the exhaust. since the one spark on the exhaust stroke has in theory no fuel mixture to fire, it is therefore 'wasted'....

harley davidson uses this same method of ignition.

the signal comes from the points, same as the single kohlers, i would make sure that you have spark at the points first, especially since you say the coil checked out ok. 99 % of all no spark situations i come across are no spark at the points. a simple file of the contact points fixes the problem. this is usually since they have oxidized from the engine sitting not running for a length of time.........

the points should be on top of the engine under a cover about 3/4" x 1 1/2" approximately. on the same side as the fuel pump, follow the trigger wire from the coil back. 

 

 

i went through the whole coil fiasco with my kt17 just recently. while the coil primary circuit homed correctly, i had nothing on the secondary, between the post towers. a replacement harley coil fixed the problem....

heres the thread.....

 

 

post #22 has the relevant info on the coil.

Edited April 30, 2013 by Martin

[tractorbeast 27]

the kt uses whats known as waste spark ignition. both cylinders fire at the same time, one on the compression stroke at the same time as the other on the exhaust. since the one spark on the exhaust stroke has in theory no fuel mixture to fire, it is therefore 'wasted'....

harley davidson uses this same method of ignition.

the signal comes from the points, same as the single kohlers, i would make sure that you have spark at the points first, especially since you say the coil checked out ok. 99 % of all no spark situations i come across are no spark at the points. a simple file of the contact points fixes the problem. this is usually since they have oxidized from the engine sitting not running for a length of time.........

the points should be on top of the engine under a cover about 3/4" x 1 1/2" approximately. on the same side as the fuel pump, follow the trigger wire from the coil back. 

 

 

i went through the whole coil fiasco with my kt17 just recently. while the coil primary circuit homed correctly, i had nothing on the secondary, between the post towers. a replacement harley coil fixed the problem....

heres the thread.....

 

 

post #22 has the relevant info on the coil.

Thanks Martin, the coil sec. ohms are right on. 9.9k i believe, don't have my notes. Is there a way to check the ac signal at points with the engine cranking with a multimeter meter? The tractor has not been ran much, the points probably need cleaned.

[Martin 2,133]

on a correctly operating ignition system you would be measuring dc voltage at the points. you should get a variance between 12 volts and 0 volts at the points with a voltmeter as the engine cycles through its 4 strokes. connect the + lead to the point wire and the - to ground....as the points open and close you should have a change in voltage from one extreme to the other. the easiest way for me to check for spark is when looking at the point gap roll the engine over till the points are closed. then using a long screwdriver or similar, push on the metal frame of the arm of the points to seperate the point surfaces. you should see a nice blue spark jump that gap. if you have a weak or no spark, try cleaning the points with a points file. turn off ignition voltage to coil, seperate and place the file between the points and clean up the surfaces a little, keep the file flat and true to the two point surfaces. a couple of strokes, remove the file and turn on ignition again, separate the point gap and see what sort of spark you have, if everything else with the ignition system is working properly, you should get spark to jump the gap. now keep in mind that just because you can get spark at the points, doesnt mean that your getting spark at the plugs, so that would be your next check. if everything is installed, i.e. the only ignition parts not assembled is the points cover, roll the engine over and see if it fires. if not then pull a plug and check by rolling it over while connected to the plug lead and grounded to the engine. if you are game you can do a quick check by putting your hand on a plug wire while rolling the engine over. quick, but uncomfortable. sometimes if youre chasing an ignition problem, that shock from a spark is a welcome relief!!!!!

 

ive noticed youve mentioned references to the charging system a couple times, the ac signal, and stator.....

the ignition system on these only uses a dc signal and points fire, no stator. these references are usually made to the charging system on these engines, the stator (behind the flywheel) supplies ac voltage through two wires to the rectifier, this voltage is then converted by the rectifier/regulator to dc voltage. this has nothing to do with the ignition system in questiion though, just wanted to clear that up. 

Edited April 30, 2013 by Martin

[tractorbeast 27]

Martin. Now I see why I have been so confused, I though the flywheel trigger was used in starting the engine. Thanks for the explanation. So basically the pushrod to the Cam opens and closes the points, which allows the negative DC voltage from the battery/Engine ground to be sent to the secondary(negative terminal) of the coil.

1. The stator, rectifier have nothing to do with starting a points, & condenser small engine.

2. The points, condenser, & coil have nothing to do with charging the battery.

[tractorbeast 27]

on a correctly operating ignition system you would be measuring dc voltage at the points. you should get a variance between 12 volts and 0 volts at the points with a voltmeter as the engine cycles through its 4 strokes. connect the + lead to the point wire and the - to ground....as the points open and close you should have a change in voltage from one extreme to the other. the easiest way for me to check for spark is when looking at the point gap roll the engine over till the points are closed. then using a long screwdriver or similar, push on the metal frame of the arm of the points to seperate the point surfaces. you should see a nice blue spark jump that gap. if you have a weak or no spark, try cleaning the points with a points file. turn off ignition voltage to coil, seperate and place the file between the points and clean up the surfaces a little, keep the file flat and true to the two point surfaces. a couple of strokes, remove the file and turn on ignition again, separate the point gap and see what sort of spark you have, if everything else with the ignition system is working properly, you should get spark to jump the gap. now keep in mind that just because you can get spark at the points, doesnt mean that your getting spark at the plugs, so that would be your next check. if everything is installed, i.e. the only ignition parts not assembled is the points cover, roll the engine over and see if it fires. if not then pull a plug and check by rolling it over while connected to the plug lead and grounded to the engine. if you are game you can do a quick check by putting your hand on a plug wire while rolling the engine over. quick, but uncomfortable. sometimes if youre chasing an ignition problem, that shock from a spark is a welcome relief!!!!!

 

ive noticed youve mentioned references to the charging system a couple times, the ac signal, and stator.....

the ignition system on these only uses a dc signal and points fire, no stator. these references are usually made to the charging system on these engines, the stator (behind the flywheel) supplies ac voltage through two wires to the rectifier, this voltage is then converted by the rectifier/regulator to dc voltage. this has nothing to do with the ignition system in questiion though, just wanted to clear that up. 

I have found a very weak-and intermitant spark, white in color. In checking the battery cables, the positive cable pulled out of the connector at the battery. I have a lot of wiring to clean up before I can get back to the points. I have read the KT service manual,but I still dont understand the points settings and adjustment. Anyone have a good pictorial article on this subject?

[Martin 2,133]

if you search kohler static timing on this forum, there are numerous threads on the subject. google 'kohler static timing' as well....

 

cant find the cub cadet pdf im looking for but there are these to look at....

 

 

i like to use the timing light method as mentioned in this post......

 

excellent pdf here....

 

http://www.mywheelhorse.com/graphics/file/KohlerK-SeriesStaticEngineTiming.pdf

 

these are all for single cylinder kohlers but the principle and parts are basically the same. you should have a opening in the blower housing to see the flywheel marks. and the points are similar just in a different position on the block......

Edited May 2, 2013 by Martin

[tractorbeast 27]

if you search kohler static timing on this forum, there are numerous threads on the subject. google 'kohler static timing' as well....

 

cant find the cub cadet pdf im looking for but there are these to look at....

 

 

i like to use the timing light method as mentioned in this post......

 

excellent pdf here....

 

http://www.mywheelhorse.com/graphics/file/KohlerK-SeriesStaticEngineTiming.pdf

 

these are all for single cylinder kohlers but the principle and parts are basically the same. you should have a opening in the blower housing to see the flywheel marks. and the points are similar just in a different position on the block......

Thanks again Martin, some good links, especially the "static Timing" search. You got me in the right direction. For the good or bad of it, I'm from the era when cars had points to set. Points and dwell angle were in the same sentence., and nothing to do with timing(as I remember it anyway) Guess that's why I'm somewhat confused on the issue. From reading the forums, I see I'm not alone, and I've set many points with a matchbook in my lifetime. That was the defacto standard back then- heck, where can you even get a matchbook now?  There still seems to be a lot of confusion out there about the subject. I dont even want to get into that!... take care.