No Fire To Spark Plug 149 Cub Cadet

[R Bedell]

Then as I moved the ign. key from start to run, the tractor started.

Buy and install the CORRECT Ignition Switch.

[jbrewer]

Originally Posted by Dart1917

You had spark while cranking with the spark plug out and grounded to the head so I don't think there's a problem with the switch. Check voltage at the positive coil terminal while cranking. I'm thinking without the ACR working it's drawing down the voltage and you get a weak spark or no spark. When you let off the starter the voltage comes back up enough to fire as the engine rolls through.

This sounds like a winner. I suppose you could verify this with an extra 12v battery clip leaded to the battery side of the coil , after disconnecting the existing 12v line and the negative to ground. It this was the problem the engine should then fire.

The battery voltage would indeed sag the most as the piston reaches TDC and the current load on the motor/gen is the highest and the voltage lowest.

Interesting puzzle. The ACR is a really useful feature :-)

[Gompers]

Originally Posted by jbrewer

This sounds like a winner. I suppose you could verify this with an extra 12v battery clip leaded to the battery side of the coil , after disconnecting the existing 12v line and the negative to ground. It this was the problem the engine should then fire.

The battery voltage would indeed sag the most as the piston reaches TDC and the current load on the motor/gen is the highest and the voltage lowest.

Interesting puzzle. The ACR is a really useful feature :-)

No, I would think it would still be in the same boat. The only place voltage is coming from when it’s cranking is the battery. So a voltage drop too low to fire is going to still happen unless there’s another or bigger power source (battery, jumper pack or whatever).

Jumping the coil with a different wire would rule out the key switch though.

Wouldn’t have to disconnect anything, just run 12v to positive side of coil. Gotta leave the ground connected to the coil or there’s nothing the points can do to make it fire.

[jbrewer]

Originally Posted by Gompers

No, I would think it would still be in the same boat. The only place voltage is coming from when it’s cranking is the battery. So a voltage drop too low to fire is going to still happen unless there’s another or bigger power source (battery, jumper pack or whatever).

Jumping the coil with a different wire would rule out the key switch though.

Wouldn’t have to disconnect anything, just run 12v to positive side of coil. Gotta leave the ground connected to the coil or there’s nothing the points can do to make it fire.

Yes I wasn't clear. Use a spare battery to provide the 12V to the coil. Disconnect existing + coil wire coming from the keyswitch.

If the voltage sag was the problem it should start then. With a jump box this should be pretty quick if the OP has one around.

I mention disconnecting the existing + coil wire during this , to make sure that if the existing battery is sagging while cranking, the 12V from the jump box would see that load and try to feed it thru the switch, which wouldn't be good.

[J-Mech]

Originally Posted by jbrewer

Yes I wasn't clear. Use a spare battery to provide the 12V to the coil. Disconnect existing + coil wire coming from the keyswitch.

Gompers is right. You don't need to disconnect anything to add voltage to the coil. You can just use another battery, or jump pack as a test to confirm.

Originally Posted by jbrewer

I mention disconnecting the existing + coil wire during this , to make sure that if the existing battery is sagging while cranking, the 12V from the jump box would see that load and try to feed it thru the switch, which wouldn't be good.

What are you talking about? What load will it feed through the switch that "wouldn't be good"?? Extra voltage to the coil? It will only feed 12V (or whatever the nominal voltage of the jumper pack is) and only at an amperage rate needed. It won't hurt a darn thing. It's not going to overload the system. IT WILL BE FINE.



To the OP:
It's a simple test. You can try to watch the voltage at the coil while cranking, but depending on your DVOM, the voltage flux may happen to quickly to see on the meter. (Voltage fluctuates, so the meter averages the readings and puts the average on display. It may happen to fast for it to give an accurate average. Seen this before.) If your meter has a graph at the bottom of the display, watch the graph, as it tends to move more accurately. If in doubt, as suggested supply the coil with 12V from another source. Just to be clean, you will need to attach B+ from the second source to the coil, and B- from the source to either the tractor battery or the frame, for it to work.

I DO agree that you should install the correct ignition switch.

[R Bedell]

Seems like this thread is going in circles.

(A) Download the Wiring Diagram found in the Technical Library section, located on page 5.

(B) Wire the tractor per the Diagram.

(C) Ensure that the Battery is good and properly charged.

(D) Use only the correct Cub Cadet Parts.

If you simply follow through with the above, then your tractor should start & run.

The ACR thing will have to be addressed.

[Mr Bob]

Sam Mac, I bought an aftermarket switch that said it replaces the IH-60736-C1. The old switch was toast as the old style key that fit both ways would fall out. Bought a new wiring harness from a forum member, can't remember name. All wires were marked and I hooked up accordingly. I bypassed the neutral switch and the pto switch. I am going to check to see that I did bypasse both switches, then try to understand the directions that other members have given me and do the test they suggested. I am not very good with digital meters. I believe one was saying to hook a wire from another battery pos. terminal to + side of coil. Then I believe I would have to run a wire from neg. extra battery to neg. tractor battery. Hope I have it correct. Thanks for all the help and have a great day.
Bob

[jbrewer]

If the battery in the tractor is being dragged down in voltage due to excessive current draw cranking an engine without a functioning compression release, you could eliminate this as a possibility by removing the 12V connection coming from the switch and instead supplying a full 12V to the coil from another independent voltage source

If you were to NOT disconnect the existing positive lead from the switch to the coil when doing this, the jump box would source current back thru the switch to the tractor battery (which has sagged in voltage due to the cranking current). Given that the coil + wiring from the switch is #16 or some such, this would not be a good thing. If you want to see what current flows from a fully charged 12V battery into one that's sagged down to 8 or 9 volts thru a #16 wire, please do it outside with safety glasses.


Battery voltage sags during all cranking, especially the little tractor batteries. I have no idea how low a voltage sag (caused by hard cranking) will cause a coil to not fire across a plugs spark gap

Regardless it's simple enough to replace the voltage coming from thru the switch with 12v from elsewhere to see if this is the issue. It's a 2 min test .

[jbrewer]

Originally Posted by Mr Bob

I believe one was saying to hook a wire from another battery pos. terminal to + side of coil. Then I believe I would have to run a wire from neg. extra battery to neg. tractor battery. Hope I have it correct. Thanks for all the help and have a great day.
Bob

Hi Bob
Yes, that's right. IF the issue is that the coil doesn't have enough primary voltage to fire the plug due to the fact that it's loaded down heavily by cranking, that is a quick test.

Disconnect the small 12V lead coming from the switch to the coil. (don't let it touch ground cover it with tape during the test) . Hook the + from another 12V source to the now empty terminal of the coil and the - from the that source to a good ground on the tractor frame or bolt somewhere.

Then crank the engine and see what happens...

[twoton]

Been reading along on this (even though I can still only see out of one eye) and am finding this very interesting. Just wondering Mr Bob, do you plan on fixing the ACR?