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buckhornbob

KOHLER CH22S - No Spark - Need Help

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Update -

I can't find any dealers within a two hour drive that have the equipment to check the SAM when it is not on the tractor so, I think I will have to bite the bullet and order a replacement SAM - pricey at around $140 CDN + tax especially when I see Pats Small Engines selling it for under $50 US - problem is they will NOT ship to Canada.

 

Bob

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Have a friend here send it,unless like me you don't have any friends here :eusa-doh:

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Bit the bullet and bought a SAM unit - turns out to be about $30 cheaper to buy it through a John Deere supplier than a Wheel Horse supplier - identical KOHLER part #

 

Hopefully it will be installed today and I will hear the good news later that my tractor is up and running and ready for the snow blower install.

 

Fingers and toes crossed

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Any update?

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Update!! My fix-it buddy emailed this evening and here is his update

 

Started the installation of the new SAM. It took a couple of hours but we now have a good blue spark at the plugs. I  tied down the wires that run to the mags but had a little difficulty getting the zip ties around the intake manifold. Once I removed the 2 dead mice it went on with no problem. All 4 small 10mil bolts broke taking the shroud off so I'm drilling and tapping new holes . There is also a loose bolt that holds the steering box in place which is now tight. I'm glad we can put things back together. Will update my progress  when I have more to add. Thank heavens we got sparks.

 

Looks like we are moving in the right direction.

Thanks to all who helped travel down this path.

 

Bob

 

Bob

Edited by buckhornbob

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Update - but the news is not great!!  My fix-it buddy sent me this message last night:

 

I don't have good news . Everything was going well and when I got it back together  the tractor started and ran for a few seconds. It stopped and when I  tried to start it again the battery didn't have enough power to turn it over fast enough. I put the charger on it for about 15 min then tried it again. It rolled over OK but didn't start. I checked to see if the plug was firing and it was not . I changed a couple of the relays that the kill switch is part of but that didn't help. I felt good when I saw that nice blue spark earlier but that feeling has passed.

 

Based on earlier advice to make sure we have 550 RPM,we are working now on a full recharge of the battery to try it again.

 

Failing that, I may be left with no choice but to call in the dealer (a move of last resort) unless someone has an idea we have not yet tried.

 

As always, any advice appreciated.

 

Bob

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Another bit of info from my fix-it guy.  Could really use some direction on this if anyone has any insights.

 

I got to spend some time on the tractor today. It looks and feels like I'm back to square one. I'm trying to think if I hooked some thing up wrong , but I haven't found anything yet . I would rather go over everything again before I have to take the motor back out again. If your forum group have any suggestion to save me some time I would be grateful. I did give the battery a good charge this morning so I'm sure I was getting the 650 plus  rpms.I did get a few visitors this morning and they all had suggestion on what they would do but I'm not comfortable shorting out  the new and expensive parts that you have bought. I'm beginning to think that the brief run time you had just before you brought it here is the same as the the brief run time I had when I put it all back together. The trick is to find what caused it. I'm going to look at everything I can before I take it apart. I'm hoping your knowledgeable forum can come up with an answer. Talk to you soon 

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a few thoughts,

 

electronic igntion systems do not like to run off the pulsed DC output from battery chargers. If you are trying to start the engine on a battery with severly reduced capacity, the larger engines - especially the electronically controlled ones - may refuse to start properly.

 

My next suggestion is to have your tech guy perform a load test on the current battery. If the engine can not sustain normal crank speeds on repeated attempts, the battery capacity may be insufficient. Charge the battery overnight on the low amps setting and load test in the morning.

 

I would also caution against recharging the battery or attempting to crank the engine with the high setting on the battery charger. Some of the 200+ amp chargers can apply over 20 volts to the electrical system if the tractor is started using the high charge setting.

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Bob,

 

I was reading a thread on another forum about a person with a wood chipper that has the same Kohler engine.  He had a very similar problem and tried many of the same things you did.  In the end he found that the problem was a poor ground connection from the battery to the engine.  His engine would always crank, but no spark.  He could not figure out why improving the ground connection solved his problem, but it worked for him.  I think he even had the similar issue of not getting a spark with the kill wire removed.  Maybe a quick test could be to take a battery jumper cable and connect one clamp to the negative battery post and the other end of that wire to a good ground on the engine and see what you get (no connections to the other wire in the jumper cable).  Thought I would pass it on just as a point to look at. 

 

Rick

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Bob,

 

I pulled out the Kohler shop book again, and in order to isolate the problem between the engine and the wiring on the tractor they suggest the following:

 

"Locate the plug connectors where the wiring harnesses from the engine and tractor are joined.  Separate the connectors and remove the white "kill" wire from the engine side connector.  Rejoin the connectors and position or insulate the kill lead terminal so it cannot touch ground.  Try to "start" the engine to verify whether the reported problem is still present."

 

a.  If the problem is gone, the electrical system on the tractor is suspect.  Check the key switch, wires, connections, safety interlocks, etc.

 

b.  If the problem persist the condition is associated with the ignition or electrical system on the engine.  Leave the kill lead isolated until all testing is completed.

 

I'm seem to remember somewhere in the Kohler manual a statement that the SAM is very touchy when it comes to good grounds.  I'm wondering when your fix it man got the good spark, I don't think he had the shrouds installed yet.  Did he have something temporarily wired to perform the test, and achieved a better ground than when the shrouds were reinstalled.

 

Another quote from the Kohler manual, "reported ignition problems are most often due to poor connections.  Before beginning the test procedure, check all external wiring.  Be certain all ignition related wires are connected, including the spark plug leads.  Be certain all terminal connections fit snugly.  Make sure the ignition switch is in the run position.  NOTE:  The CD ignition systems are sensitive to excessive load on the kill lead.  If a customer complains of hard starting, low power, or misfire under load, it may be due to excessive draw on the kill circuit."

 

Going back to the beginning of your problem, where you lost spark on both coils at the same time, and replacing the coils didn't fix the problem, it lead us to the SAM.  Where we only got spark for a moment after installing the SAM, but lost it after re-assembly of the shrouds to the engine, I'm leaning more to a wiring problem, possibly with the kill wires that are under the shrouds.  Your man noted that he removed two dead mice.  Could there be a break in the kill wire that went unnoticed, and the break is such that when the wire is ben in just the right position you get a good connection, but when he installed them back to their original positions the wire opened up again?  If it were me and I had to open it up again, I might just replace the kill wires to be sure they are not the issue.  The Kohler manual also states to remove corrosion and any dielectric grease from all connections.

 

I have to go move some fresh snow today with my 522xi.  I am going to pull the wire off the oil sentry sensor to see what happens.  I don't know if it will crank or not, we will see.

 

Rick

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Hi Rick

Thanks for both of your comments.  I have passed them along and am hoping for the best.  These grounding/electrical issues are surely sent to try us.

 

My buddy is a very thorough guy but even he {grin} can miss something.  I do have lots of faith in his determination to figure this out.

 

Wish I could say I am out moving fresh snow today but right now I am paying a guy to do that.

 

Bob

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Update

 

Hated to do it but I had to go to the dealer.  My fix-it buddy says it is only the third thing in over 35 years that did not leave his shop running.  Kohlers must be special.

 

Dealer says he has it running - something to do with diodes in the electrical system - and I may have it back on Monday.

 

Will post more details when I have had a chance to talk with the mechanic who did the work.

 

Bob

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Final Chapter

 

I picked up the tractor from the dealer a couple of days before Christmas. It seems to be operating well and today I finally got to spend some time blowing snow.

 

The report from the dealer stated the following, which I am sure will make sense to some and maybe even help if you experience the same "no-spark" problem I had:

 

Test for spark - none - pulled engine and removed blower housing.  Removed coils and checked resistance. Valves both OK.  Checked test SAM unit - OK.  Went through engine wiring harness.  Found bad connections at in-line diodes - soldered instead of crimped. Installed ignition system & blower housing.  Ran on bench. Reinstalled engine.  Tried to start - not firing with key in start position.  Put key in run position - jumped starter at solenoid.  Unit started and ran. Went through tractor wiring harness& checked/cleaned connections. Ran OK.

 

Hope it continues to operate like it did today.

 

Bob

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Bob,

Thanks for the update, glad to hear that you are running on all cylinders and moving some snow. No real smoking gun in the solution, possibly a number of high resistance or bad connections from the sounds of it. Do you know if the previous owner lived in a very high humidity area, stored the tractor outside, and or was in the habit of hosing down the machine to clean it off? The next nice warm day, I'm going to take a look at some of the connectors on my tractor to see if there is a corrosion issue going on. My cruise control is not working on one of my 5xi, maybe this is something for me to investigate.

I don't see the diodes that the repair shop referred to in the Kohler shop manual or the Wheel Horse schematic, which doesn't mean that they aren't there. Save Old Iron, any idea where they may have used the diodes? I see that the 3amp stator has them per the Kohler manual, but I don't see them anywhere else.

Hopefully you have gotten the bugs out of it and will enjoy plenty of seat time from this point on. :) 

Rick

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