KOHLER CH22S - No Spark - Need Help

[buckhornbob 13]

Hi

I recently bought a 1999 Wheel Horse 522xi - Model #73560, Serial # 8901636

 

It has a 22 HP Kohler Command

Model  - CH22S,

Family - SKH624U1G2RA

Serial - 2802703221

 

One day it was running just fine and the next day it would turn over like crazy but would not start.  I tried putting a little gas straight intop the carb and still nothing.

 

Checked for spark at the plugs - nothing.

 

Called my friend who is way more mechanical than me.  When he looked at it he said it would be best to get  it into his shop and he would try to work on it between other jobs.

 

He got to the point of concluding that both coils may be the problem (a rare possibility but possible none-the-less) so I bought replacement coils - Oregon 33-518 - still nothing.

 

My friend consulted with a friend of his who runs a small engine shop and who said these Kohler Command engines can be a real challenge but that my friend had done everything he would recommend to narrow in on the problem.

 

Can anyone shed any light for us?  I am the computer guy and my friend is the mechanical guys so if you need clarification on what has been done, please ask.

 

It would be very helpful to know if there is a way to test these coils when there are not mounted on the engine.

 

We really appreciate any ideas, advice, suggestions or direction.

 

Thanks

Bob

 

 

[AMC RULES 37,134]

Have you confirmed it's got a good ground? 

[Save Old Iron 1,566]

Bob,

 

have your friend disconnect the kill wire from both coils and try again. Your kill wire may be shorted to ground - which would "kill" the spark output from both coils at the same time.

 

NEVER APPLY 12 VOLTS TO THE KILL WIRE. This will fry both mag coils almost instantaneously.

[Save Old Iron 1,566]

To test the new coils, just mount them on the engine, set your air gap between the coil and the flywheel, remove the kill wire(s) and start cranking the engine. The mags are self contained units and only need to "see" the magnet on the flywheel to produce a spark.

 

Some of the newer engines use a SMART SPARK system or even VARIABLE TIMING systems. Those I have no experience with and will require more in depth investigation of their ignition module connections and functions.

 

Grab an online service manual to confirm which system you are working with.

If the mag modules have more than one push on terminal, they are likely SMART SPARK or work under variable timing.

 

http://www.kohlerengines.com/manuals/landing.htm

Edited November 9, 2013 by Save Old Iron

[buckhornbob 13]

Thanks for the replies. 

My friend is away at a 93 birthday party for his aunt this weekend but I'll pass this along when he is back.

 

I am pretty sure he said there was a "black box" with wires leading to the coils.  Could this be a Speed Advance Module?  If so, is there a way to check it as there is still no spark with the new coils installed.

 

Appreciate any insights

Bob

[buckhornbob 13]

Hello - Back again after hearing from my "fix-it" buddy

 

He said

When I installed the new coils I did the SEE test, which is spining the flywheel past the coils to see if a spark is produced. When no spark appeared I rechecked the gap and tried again. I also put on new spark plugs at that time ,nothing.

 

I wasn't sure if the spark advance module was required to energize the coils so I hooked up the wire from the  spark advance to the coils (wide friction clip ). I left the kill switch wire (narrow friction clip) off just in case it was shorting out somewhere. This also did not produce a spark.

 

I then reinstalled the kill switch and tried it again. Nothing. My next thought was is there a short in the  spark advancer, since the kill switch wire also goes into the  unit as well.

 

I have no way of testing the spark advancer and am not sure if the spark advancer is required to get a spark. I'm assuming that if the SEE test does not produce a spark, the spark advance unit is required.

 

With that thought ,since no spark appears with or without the spark advancer, the unit may be faulty.

 

My next step is find out how the spark advance module is powered. Maybe all of the safety switches have to be in place before the power even gets to the spark advance module to energize the coils. Will let you know how I make out.

 

I am hoping that someone with experience on these units might be able to point us in the right direction for testing the Spark Advance Module and/or figuring out if all the safety switches need to be in place or by-passed in order to make this work.

 

Really appreciate any insights.

 

Thanks

Bob

[Rick_in_CT 156]

Bob,

 

Not sure if you and your friend have checked the kill relay on the tractor yet.  If you haven't, below will help you check the kill relay.

 

Attached is the schematic for the 522xi.  Near the bottom of page 2 is relay K1, the kill relay.  If the kill relay is not energized, the engine will crank but not start.  There are three relays mounted on the firewall, one of which is K1.  K1 has a yellow wire going to it, and on my tractor the only relay with a yellow wire is the one to the far left if looking from the drivers seat.  I would try tapping this relay with a screw driver handle and see if it starts.  If no start, I would check for power on the relay coil when trying to start. 

 

If there is anything you want me to take reading from on my 522xi let me know, I'm pretty good with a VOM. 

 

Rick

522xi Schematic Pg1.pdf

522xi Schematic Pg2.pdf

[buckhornbob 13]

Hi Rick

Thanks for the schematics.  They are a little different from the ones my fix-it friend and I were looking at because the ignition coils have two wires PLUS the spark plug wire.

 

Will pass along the kill switch information (thanks) and ask about any reading he might want.

 

Cheers.

Bob

[Save Old Iron 1,566]

google GARDNER INC ENTIRE STUDY GUIDE KOHLER

 

the link should download a technicians study guide which outlines complete theory and testing of the multi terminal magneto smart spark system

[buckhornbob 13]

Thanks SOI

I got the manual and sent a copy of the electrical portion to my buddy.

 

He had sent the following earlier this morning so I hope he is on track for some positive results.

 

I did a bit of digging into what powers this unit and it looks like the power comes from the key switch, I did find  a poor connection at the fuse block at the main fuse. I'm going to take it off and find out why the power goes through one minute and not the next. It may not be the cause of our problem but it's not right . So far I can't get power out of the spark advance unit.

 

The intermittent  power at the main fuse causes all 3 relays to make a clicking sound. Something is happening there but am not sure if the one with the yellow wire is working properly. Since all 3 relays are the same I'll switch them to see if I can get a spark. I'll repair the intermitant power problem at the fuse block first.

 

Once again, any insights appreciated.

Bob

[Save Old Iron 1,566]

 find out why the power goes through one minute and not the next. It may not be the cause of our problem but it's not right .

 

The intermittent  power at the main fuse causes all 3 relays to make a clicking sound.

fuse holder issues are not unusual on 5xx series

 

I believe you are on the right track.

 

Also consider checking the condition of the battery and be certain the cranking rpms are above 550 {as stated MANY times in the service manual}  My 23hp verts refuse to fire if the battery cant spin them fast enough.

 

.

[doc724 925]

I have similar occasional problem like this with my 520xi with a CH20 engine.  The engine dies when I turn on the PTO.  I just jiggle the seat switch and it goes away.  Seems simplistic, but you never know

[Save Old Iron 1,566]

Doc,

 

good point for killing an already running engine.

 

However, the electronics don't monitor the seat switch for starting purposes.

[Rick_in_CT 156]

Doc,

 

On the 5xi series, if the seat switch opens while the PTO is engaged, it takes the power off of the "kill relay" coil (K1), and shuts down the engine.  If a jiggle of the seat switch fixes the problem, you may have a bad connection in the connector going to the seat switch, a bad wire in this part of the harness, or a seat switch that is going bad.  The seat switch closes the circuit when you sit on the seat.  During normal operation with the PTO engaged cutting grass, if I lean too far off the seat to grab a fallen branch, the motor will start to shut down.  Likewise if you get off the seat with the PTO dis-engaged, and don't set the parking brake, the engine will shut down.  Big Brother is watching you!!

 

On the 5xi, in order for the starter to engage, the seat switch must be made, and the parking brake must be set so that it's interlock switch is made as well.  If neither of these are made, you will not get the starter to crank.  Just as a point of reference, the original post in this thread is a situation where the engine cranks, but no spark.  An open safety interlock switch prevents the starter from cranking, so I think we that the safety interlocks are all working on buckhornbob's tractor.

 

Pretty interesting how all of this stuff is interconnected.  And to think we only purchased it to cut the grass, we weren't going to the moon!

[Save Old Iron 1,566]

Doc, Rick

 

interestingly enough, the seat switch is ignored on the 98 models and is monitored on the 99+ year models.

[buckhornbob 13]

My fix-it buddy was able to report the following back to me:

 

I got the fuse box electrical  to stop going on and off , then hooked everything up like it should be, no spark at either plug. I double checked the gap at the mags and the connections that go to them. I would like to find out if that second wire has any thing to do with the  spark at the plug

 

Any help guys?  Winter is approaching and I really need to get my snowblower mounted.

 

Thanks

Bob

[Rick_in_CT 156]

Bob,

 

I scanned the pages from my Kohler manual for the smart spark, see attached.  Sorry for the page orientation, the manual is a bound book and would only go one way into the scanner.

 

Hopefully this helps your mechanic.

 

Rick

Smart Spark.pdf

[RMCIII 838]

Doc, Rick

 

interestingly enough, the seat switch is ignored on the 98 models and is monitored on the 99+ year models.

I have a 1998 518xi. Hate to disagree, but it is monitored, the same that year also.

[buckhornbob 13]

Once again my fix-it guy has responded as follows:

 

Think I got the fuse box back together cause the dash lights stay on now and I'm getting a steady clicking sound under the steering wheel. I was hoping to get a spark at the plug but that didn't happen. There doesn't seem to be any power at the second wire to the mag which comes from the spark advance unit. I wound like to put this thing back together soon but would like to know  if i need to do anything at the mags before I put them away under all the housing. I've gone over all the information again that you sent me and it seems to come down to the Smart Spark unit or the kill switch relay . I'm going to switch the relay one more time and then we'll have to figure out how to test the other part.

 

So, once again I am asking for some guidance here.

 

Do I have to find a shop with a Smart Spark tester - either 25 761 21 S  or 25 761 40 S

Can this test be done with the SAM completely removed from the tractor?

 

Any other insights welcomed.

 

Thanks

 

Bob

[Save Old Iron 1,566]

 

Doc, Rick

 

interestingly enough, the seat switch is ignored on the 98 models and is monitored on the 99+ year models.

I have a 1998 518xi. Hate to disagree, but it is monitored, the same that year also.

 

 

Interesting. This wouldn't be the first mystery made deeper by the demystification guide.

 

The circuit in the Toro demystication guide for the 1998 522xi shows the seat switch is not monitored for kill purposes. (don't know about the 518xi ). Per the schematic below, the PTO needs to be disengaged and the BRAKE safety switch ON. The SEAT switch will certainly become a player when the PTO switch is engaged.

 

Regardless, Bob states he has a 99, and he has removed the KILL wires from the mags. Under these conditions, the status of any safety switches should become irrelevant.

 

Unless........ something like a kill signal from the oil pressure sensor sends a kill signal to the SAM module. I don't believe the KILL signal comes into or goes thru the SAM. Back to the schematics to check for sure.

.

.

.

Edited November 20, 2013 by Save Old Iron

[Save Old Iron 1,566]

I've gone over all the information again that you sent me and it seems to come down to the Smart Spark unit or the kill switch relay .

 

Do I have to find a shop with a Smart Spark tester - either 25 761 21 S  or 25 761 40 S

Can this test be done with the SAM completely removed from the tractor?

 

Bob, if you have removed any possibilty the mags are grounded (by removing the KILL wire at the mags)

 

AND

 

you have confirmed 12 volts available to the SAM module when it is cranking,

 

I agree the SAM module is highly suspect.

 

I have never experimented with a Toro SAM but the operation theory remains the same. The SAM senses the engine RPM and introduces a delay to the 2nd "FIRE" terminal on the mag(s). As the engine RPM increases, the SAM will gradually cut back on the delay it introduces and effectively advances the spark to the mags. More delay at low RPMS = easier starting, less delay / more advance at higher RPM = potentially more power.

 

The logic then boils down to:

 

IF the kill relay is NOT grounding the mag kill termnal

AND the engine RPMS are above 550

And the SAM is powered up and functional

 

Then the SAM calculates a delay appropriate to the current RPM of the engine and sends an output signal on the BROWN wires to the mags

 

The mag(s) then fire if they are functional.

 

p.s. since both "FIRE" wires on the mags are color coded BROWN, they are most likely interchangeable.

I'm not sure if the physical length of the wires will prohibit interchanging them. The point is both mags are likely fired at the same time and if one mag is bad, the other should fire. If neither fire, the SAM appears the likely culprit.

[Rick_in_CT 156]

I have come to the same conclusion as Save Old Iron, it is really looking like the SAM as long as the kill relay has been confirmed as ok.  If you have a Wheel Horse/Toro dealer in your area, I would give them a call and see if they can test the SAM.  The Kohler manual says that the SAM can be tested removed from the engine.  I have not been able to confirm if the oil pressure switch is tied into the SAM or not, but I would make sure that the crankcase has the correct oil level.

[WH nut 553]

By looking at the diagram, if all wires are removed from the mags you should have spark. By the diagram ground the mags is all any wire does.

[flyovrcntry 115]

:confusion-scratchheadblue:My only advice about electronics is obey the all knowing squirrel .You will be rewarded with a nice blue spark

[buckhornbob 13]

:confusion-scratchheadblue:My only advice about electronics is obey the all knowing squirrel .You will be rewarded with a nice blue spark

If you are referring to SOI, I agree.

Just waiting patiently for my fix-it guy to let me know if I have to buy a SAM unit.

Any recommendations for best price on one of these?

Thanks