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Cub Cadet model #: 17AREACS010
Serial#: 1E309H10009
Engine: Kohler 7000 SERIES 22 hp
Model#: KT725
Serial #: 4906400854
Build Date: 03/05/2019

My background: Ford driveability tech for 25+ years - typically don't get stumped on engines but this is the exception. Engine has the updated (came new that way) MDI ignition system - about as simple as an ignition system gets. After step-son mowed my yard (over 6 weeks ago) I have not been able to get it to start. Logic says 3 elements to combustion - air, fuel, ignition. I'm still breathing so I'm ruling out the air issue. Engine cranks over normally but no start even using starter fluid - not even a hiccup of a light off. Replaced both coils - no help. Removed single (grounding terminal) from both coils and re-attempted start - no joy. Removed flywheel to check stator magnets - all okay. Checked spark with test plug - no spark. Checked again with using regular spark plug - very weak spark detected. So to my thinking the only thing left unresolved is the trigger magnet on the flywheel - have any of you had issue with these before? It looks like one has to replace the entire flywheel which I'll do if it comes to that but they are in excess of $200 so not want to pull that trigger unless that's the consensus of the forum.

Thanks for any help you may have! Mike

Of 25 years in business have never seen the magnet for the igntion modules fail on any engine. So I would go down the path of the new modules are bad, or you have a short that is sending 12 volts to the coils which will let the factory smoke out. And everybody knows that electronics operate on smoke. When the smoke comes out they stop working.

I'm inclined to agree with your first thought of bad (new) modules - I did cheap out and went for the Chinese knockoffs - had fair reviews but you get what you pay for. This is an MDI system - only one wire going to each coil and that's simply a ground wire coming from ignition switch to kill the engine. I'll bite the bullet and order OEM coils (modules). The first year of ownership my bestest friend borrowed it weekly for the entire summer then finally broke down and an identical unit - so now is "payback" time - I've been using his for several weeks now but its getting old and I'm getting older so time to git r done. Thanks for your reply.

Check the kill wire
It should be open for the engine to run and ground to stop the engine
All of the safety switches apply a ground connection to that wire to stop the engine
The Hall effect chip that times the coils works on the negative side of the induced voltage so if it see the smallest amount of + voltage the circuit gets fried
People not familar with magnetos think it is a Kettering ignition and will "test" the coils by flicking battery power to the kill wire which confirms the coils are toast
Do you still have the original coils ?
did you check them kill wire removed ?

bertsmobile1 said:

Check the kill wire
It should be open for the engine to run and ground to stop the engine
All of the safety switches apply a ground connection to that wire to stop the engine
The Hall effect chip that times the coils works on the negative side of the induced voltage so if it see the smallest amount of + voltage the circuit gets fried
People not familar with magnetos think it is a Kettering ignition and will "test" the coils by flicking battery power to the kill wire which confirms the coils are toast
Do you still have the original coils ?
did you check them kill wire removed ?

Click to expand...

You may have missed it in my OP - I did remove both grounding circuits and attempted to start. It cranks over at normal cranking rpm but no light off with or without ground wires connected. I never applied any direct voltage to the coils. New OEM coils are arriving Sunday - I'll post the results. Thanks for the tips.

have you tried turning the coils over ?
they are polarity sensitive
The correct way the induced voltage is negative
Upside down it is positive so will not work as the hall trigger closes after the the max flux has past
Usually the kill wire tab goes underneath and often that has at least 1 HT lead pointing the wrong direction
From memory Honda is the only company right now that makes handed coils

bertsmobile1 said:

have you tried turning the coils over ?
they are polarity sensitive
The correct way the induced voltage is negative
Upside down it is positive so will not work as the hall trigger closes after the the max flux has past
Usually the kill wire tab goes underneath and often that has at least 1 HT lead pointing the wrong direction
From memory Honda is the only company right now that makes handed coils

Click to expand...

That's a good piece of information - I did not know of the polarity issue. Thanks!

bertsmobile1 said:

have you tried turning the coils over ?
they are polarity sensitive
The correct way the induced voltage is negative
Upside down it is positive so will not work as the hall trigger closes after the the max flux has past
Usually the kill wire tab goes underneath and often that has at least 1 HT lead pointing the wrong direction
From memory Honda is the only company right now that makes handed coils

Click to expand...

Some of the Kohler V-twin engines with fixed ignition timing have one of the two modules mounted upside down

Which one?

Sandbuster said:

Which one?

Click to expand...

From your serial number it appears your engine has the 32 854 06-S CDI fixed timing modules not the MDI spark advance modules. Trying to use the MDI modules on an engine that was set up with the CDI fixed timing will have no start or poor running due to the spark timing being off. Here are the mounting instructions for the CDI modules used on your engine

CDI modules are installed on cylinder 1 with single
kill tab away from cylinder/towards you, and on
cylinder 2 with single kill tab towards cylinder/away
from you.

Thank you (ILENGINE) so much for your clarification. New OEM modules arriving tomorrow - with your information I now have high hopes of success (it will be so nice to be able to use my own mower again!).

Modules arrived late this afternoon - will install tomorrow using your info. BTW, which cylinder is number 1? I think I can figure out #2....

Sandbuster said:

Modules arrived late this afternoon - will install tomorrow using your info. BTW, which cylinder is number 1? I think I can figure out #2....

Click to expand...

number one is the one closest to the flywheel. they may even be numbers molded into the aluminum with 1 and 2 on either the cylinder or the head

look also for any kill wire that has wire insulation damage and is grounding on the engine. it happens. Some model mower do a pretty good job of sleeving kill wires with heat and chaff material ...some just allow the wires to rest on the cylinder cooling fins and over time, you end up with a kill wire that is grounding to engine.

I give up. Unit is back on trailer and covered up. Local service shops are 4-6 weeks out. I'm on their call list....