No Fire To Spark Plug 149 Cub Cadet
 

Had all the bolt on parts off engine and pulled engine to pull oil pan. Was having trouble with the tab on the cam shaft that opens exhaust valve before firing. Tab broke off. Retrieved tab from engine that had broken off and put oil pan back on. Put engine back in frame and put everything back on that I had taken off. Put oil back in and tried to start engine. Would not start. No fire to the spark plug. Checked wiring on coil and had black wire from ign. on pos. side of coil. Wire from points and condenser wire are on the neg. side of coil. Got my cheap Harbor Frt. digital meter out to start checking the coil. Set meter to 200 ohm setting and got a reading of 4.2 ohms from pos. to neg. on coil. No reading from pos. or neg. to ground. Set meter to 20k ohms to check plus to tower. Got a reading of 7.4. Do not know if this means 7.4k or just 7.4 ohms. Reset timing using static method and a test light. Took a compression test and it read 98lbs. compression. Don't know what it should read. Leaked down about 2lbs. in about 5 min. Not sure you can do a leak down test with this gauge. All this and still will not fire. Getting fuel to carb. Had fuel on spark plug when I removed it. Sorry for the long post. All help appreciated. Have a great day.
Bob

Resistance should be approx. 11,500 ohms. I'd say you have a bad coil. Do you have another Kohler K engine you can swap one out of?

Wow, lots of things changed during that operation.

If you lay the spark plug on the head so that the flats of the plug are resting against the (grounded) cylinder head and crank the engine, do you see any spark ? (do this in a dark area , obviously). You should be able to see it and hear it.

Were you making those measurements with the coil connected?

I'd try and swap a coil (as mentioned above) too. Barring that, it's probably something you changed not a coil mysteriously going bad , even though that's possible.

I'd consider putting the ohmmeter on one side of the points and turn the engine over by hand with the other side of the ohmmeter on the points side of the coil wire. Do you "see" the points open and close? Is the condenser on the correct side (the points side) of the coil (this shouldn't make it fail, but best to check).

Is the + side of the coil @12 v when the key is on?


Summary: First determine if it's getting any spark at all. If no, we'll backtrack. There's only a couple things it could be.

Hook your test light to ground. Probe the negative terminal (points terminal) on the coil and crank the engine. Test light should flash. If not, file the points and check to make sure the wire from points to the coil is not grounding out somewhere. Common area is st the point cover.

If it flashes, check the coil tower terminal for corrosion. Replace the coil wire and spark plug as necessary.

Hard to believe a coil failed just sitting. Highly unlikely.

I think pos to neg terminals on the coil should register about 4-5 ohms. I think the coil is fine.

Like J-Mech has said, it's probably the points. I would take a slightly different approach though, being basically lazy.

Step one, clean the points. Using a small strip of sandpaper and draw it between the contacts to clean them. Try for a spark again. I've found that's usually all it takes.

If that fails, follow J-Mech's method.

I got one of these at the Chinese Freight store for about five bucks. Comes in quite handy in situations like this.

That looks like a decent buy for that price. Next time I'm in China Freight I'll snag one.

I guess one other thing for the OP:


Are you sure the spark plug cable is making good connection and is firmly seated at both ends (and clean).

Went to the garage and rechecked the things that you all said to check. Thanks for all the help. Still not running. I do have a strong spark at the plug. Tested it by putting the plug close to a ground with low light and had a good spark. Yesterday I tested it by putting a screw driver in the plug wire and putting it close to a ground. Had not turned off the lights and could not see a spark. No corrosion in the coil or my new spark plug wire. With the ign. on, I get 12.4 volts to the pos. terminal of the coil. Hooked my test light to neg. terminal of battery and cranked engine. Put test light to screw that wire hooks to to go to coil. Light flashed on and off while cranking. Removed spark plug and had fuel on plug. Cranked engine over and fuel squirted out the spark plug hole. Before I did that I took the fuel bowl off to make sure the needle valve was not stuck in it's seat. It was not. Could I have knocked a wire loose under the dash while hooking up the choke? I looked as best I could and could not see a loose wire. This engine was running before I pulled it . Any other advise? Thanks again to all that responded . Great Forum, Great people with a lot of knowledge about Cub Cadets. Have a great day.
Bob

If it's got spark and if it's got gas, we're left with compression and timing. I'd double check timing since you mention that you've re-set it.

Does it sputter or try to start at all?

Well, you said you have 12V at the coil. Not sure what wire you think you may have knocked off, but if you have power to the coil, that's all you need. If there was a wire knocked off, it would have to be something non ignition related that wouldn't affect running.... So, no. You don't have a wiring issue.

You have spark, you are apparently getting fuel. Either too much fuel, or you flooded it.

If the needle valve is sticking, or not shutting off, then you should have gas running out the carb. Like dripping/running. Should be pretty obvious.


Only a couple possibilities left:
*The fuel is bad. (You don't say anywhere how long ago it was running.)
*You flooded it and just need to pull the plug out, crank the engine to dry the cylinder some. (If you do that make sure the spark plug wire is far away from the spark plug hole, and also not near the carb. Might have fire where you don't want it.)
*Timing is not correctly set
*Something you took apart didn't get installed correctly.

Couple things I want to point out that makes me somewhat skeptical:
You stated in post 1 that you took the engine apart to retrieve a broken ACR tab. You do not say you fixed or replaced the cam. I find it surprising that your starter can crank the engine if the ACR is not working. 14hp is big motor.
Second, you stated that you had 98lbs compression. If the ACR was working, you shouldn't have that much, AND that's pretty high compression for that starter. If this engine cranks, I'm skeptical of that number.
Third, you stated you did a leak down test, but you don't know if the gauge you are using is capable of that test..... um, well, do you know how to perform a leak down test? A regular compression gauge will not do one, so just how exactly did you perform that test?? Takes a leak down test kit to do one, and it should have two gauges on it. So.... skeptical about both your compression test and the leak down test.

Alright... so does this engine have compression? If so, how much? What all did you take off of it? You say you had all the bolt on part off of it? Head? Did you remove the head?

Until we know if what you did to repair the broken ACR, kind of hard to say what the problem is. It has fuel, it has spark. I feel confident it's getting air...... should run.

How did you know the tab was broken off, or did you break it trying to bend it to get more lift. I've never been able to do that, they always break. If you don't have a working ACR, I'm leaning towards Jmechs thinking of its not spinning through compression fast enough to crank---at least I think that's what he is thinking.:bigthink: Silly idea, but if your ACR is broken and your battery is weak/small..... Of course this is assuming everything you had apart has been reassembled properly.

I was referencing + to tower as seen here.

http://www.onlycubcadets.net/forum/s...highlight=coil

That post says 7k - 12k. The manual lists 11,500 as the proper reading.

If he got 7.4 set on 20k, then he has 7400 ohms, which is on the low side.

However, now that he mentions he has spark, I'd move onto the next thing, if he doesn't have a spare coil lying around.

Thank you for your help once again Jon. I have a poor memory but your in-depth look at my problem sparked my memory. I had forgotten that I had the valves out and reseated the exhaust valve. Also had the intake valve out to clean. Had a real problem getting the valve keepers back on. Adjusted the valves as per the manual. Now to your questions.
1. Fuel is good. Not much fuel on plug but I put new spark plug in and still not starting.
2. Timing not set correctly. I set timing and checked it twice. I turned engine by hand and when test light flickered, I verified that "s" line was aligned with line on housing.
3. Broken tab and acr. I pulled the engine because I felt the acr tab was bent down and not working. After removing the oil pan the tab was indeed bent down. I tried to bend tab for 2nd time and it broke off the acr. I retrieved tab from engine thus leaving the acr not functioning.
4. Engine cranking and compression. The engine will crank if I turn the front pully so that it is back from the compression stroke. This gives it a little time to crank before building compression and once it rolls past the first compression stroke, it cranks almost as fast as it usually did before this problem. I have an older compression gauge, but I feel that it is working properly and the compression reading was 98 psi after 3 cranking rotations. The acr is not working due to the broken pin. No I probably don't know how to do a leak down test and I stated in my first post that I didn't know if you could do a leak down test with this compression tester. I do know that leak down is the amount of time it takes for compression to leak by the rings and how much leakage there is.

Going to pull the head and watch the movement of both valves. As I stated, Had a real hard time getting the valve keepers on the valves. Thank you and all the others for helping me. I would be lost with out this forum. Have a great day.
Bob

Good information Bob.

If the engine is hard to crank, then it's probably got enough compression to run. The leak down test is interesting , but even a wheezy engine should start and run , even if down on power and smoking like a chimney.

Your idea of watching the valve train is a good one, particularly while watching the timing mark and the action of the points while rotating it by hand.

Pulling the head doesn't take long and will eliminate a lot of guessing. Your patience and methodical work is really good.

Started at Last
 

Up Date!!! Started checking things again. Pulled the head and valves seem to be working ok. Put head back on and pulled on wire from points to coil. Wire moved a little at the hold down screw. Removed points and tightened wire. Installed points. Took another compression check and got a reading of 98lbs. psi. Put old spark plug back in engine (champion H12) that was in engine when I bought tractor. As I cranked the engine, I moved throttle from idle to full throttle. Engine didn't hit a lick. Then as I moved the ign. key from start to run, the tractor started. Opened garage door and rear window and let tractor warm up. Then adjusted high speed and low speed on carb. I have to turn engine just past compression so it will crank over. This is hard to do with spark plug in head. I have found that engine will not start while holding key in start position. It starts if you slowly let key back to run position. It will not start every time . It has a new intek ign. switch. Either I have the switch wired wrong or switch is bad? Thanks for helping and have a great day.
Bob

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.

I haven't had one apart, but is it possible that the keyswitch isn't keeping the contacts for the ignition circuit closed when it's in the "start" position?

It could, but earlier he had the plug out and cranked the engine and had spark. It could still be an intermittent open in the switch but I think it would be unlikely.

Just a stupid question did you buy a Cub Cadet ignition switch? Cub part # is IH-60736-C1 or did you get one that some parts kid matched up for you? :bigthink:
Edit: Cub OEM switch. http://www.cubcadet.com/webapp/wcs/s...rocessARIParts

:IH Trusted Hand:

Buy and install the CORRECT Ignition Switch.

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.

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.

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.


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.

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.

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

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 .

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...

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?:bigthink:

Hmmm,...:bigthink: So I guess Bob's out at the moment. This "test" got me thinkin about this old post about putting the ignition on a separate switch (just for discussion purposes and all, no beatin each other over the head);

http://www.onlycubcadets.net/forum/s...=33676&page=18

And I don't mean to take Don's recommendation out of context as I know he was talkin bout pullin tractors...

But, if Bob did everything that Roland suggested:

But, chose not to fix the ACR, at least not now.. that's kinda the shittuation he has, excessive compression making it hard for the starter to both spin over the motor and fire the ignition at the same time?:bigthink:

As I’m thinking bout this test and the “You gotta disconnect stuff” , “NO! You don’t gotta disconnect stuff” discussion, it makes me wonder about the proper operation of the condenser as part of the ignition system. I got this book some years ago;

https://www.amazon.com/dp/B002I8H4WE...V170RD6O&psc=0

it has some interesting information in it and with regards to function of the points and condenser;

from page 131… in the split second that the gap resistance starts to create a voltage drop in the battery current, the potential (voltage) stored in the condenser will be greater than the battery voltage across the contacts. This being the case, the condenser instantly begins discharging back through the circuit, in opposition to the battery current. Thus, it effectually heads off and instantly stops the battery current, so that the contacts make a clean break, without any arcing of current across them…..(and on and on blah blah blah).….. we say that the condenser discharge constitutes an oscillatory current of rapidly diminishing value”

So,.. without typing out the entire half page of info about this all (my arm is still really hurting) I would think that if one was to engage in this “test” the second battery source and the function of the points/condenser should be isolated from the starter circuit? Yes? No? I thought that it was a bad idea to provide a secondary ground path...

Sorry, just trying to figure this out…:bigthink:

Sounds like Bob should get a higher rated battery, put his ignition on a toggle switch and once he gets it crankin, flick the switch! Or maybe fix the ACR...

That explanation of a condenser’s function is a little simplified and, from my understanding, wrong. Capacitors (condenser in this case) resist changes in voltage, while inductors (the coil) resist changes in current. Putting the two together creates a simple oscillator.

When the camshaft pushes the points open, it breaks the circuit that is completed through the primary windings in the coil. The magnetic field that is created in the core of the coil by the current flowing through the primary windings (when the points are closed) begins to collapse and this collapse induces a very large voltage into the secondary coil windings, which flows from the secondary coil windings through the spark plug electrode and jumps the gap from the electrode to the ground creating the spark. As it collapses, it also induces a relatively large voltage in the primary winding that might jump the gap in the points.

The point of the condenser isn’t necessarily to provide voltage to fire the spark plug, but it’s to stop the current flowing through the primary winding from the collapsing magnetic field from reaching the points and jumping the gap. It’s sort of like an electrical “bumper”. The condenser charges to absorb the current spike from the collapsing magnetic field and then discharges after the current stops flowing partially rebuilding the field in the coil, which then collapses again, but less this time, charging the condenser, which discharges, but less. It’s a simple oscillating circuit that “rings” when you open the points. All this happens while the points are open.

When the points close again, it completes the circuit and the magnetic field rebuilds in the coil starting the whole process over again.

In short, the engine would run fine for a while without a condenser, but the points would be sparking every time the points opened and it would shorten the life of them significantly.

Thanks for the input there Gompers. I did simplify the explanation by deleting a whole bunch of stuff in the …..(and on and on blah blah blah).….. area. What really amazes me is how the condenser actually reverses the flow of current back through the primary coil, through the battery and the ground, and into the opposite side of the condenser. Recharged by it's own discharge. And how quickly this all happens, over and over again! That's why it seems that isolating the ignition circuit from the starting circuit during this "test" would make a lot of sense. To me anyway.

Well.... no, it wouldn't run fine. I guess you've not ever had an engine with a failed or not grounded condenser. They will backfire, buck and just all out run like crap.

But to answer twotons question (? I'm not sure there was a definitive question) no, the condenser does not need to be isolated from the cranking battery, or the cranking battery disconnected from the ignition system. It (the condenser) will do it's job when attached to the coil/points no matter what.

The cranking battery doesn't need enough "help" to spin the starter so a secondary source isn't going to backfeed. How about this.... you could just attach another battery to the tractor battery via jumper cables, and it will do the same thing as just powering the ignition separately. *IF* the issue is lack of voltage for the ignition, it will function fine.

*More shortly*

Cause ultimately, what Bob is trying to do is get some extra amps into the system.

:bigthink:.......

Maybe this will help:

Electrical systems/ electricity function exactly the same as a hydraulic (meaning fluid) circuit.
So, picture the battery as a water tower, or a pump (depending on which idea works better for you). All the wires are water lines. Some bigger, some smaller. Now the wire (pipe) coming out of the battery is a certain size, and therefore can only let so much "water" out of it. When you engage the starter, that main line is opened up all the way directly to the starter. ALL the power the battery can provide via the cable (water line) starts flowing to the starter (according to load). When that big valve opens, if the load is great enough it may pull all that fluid down that open line as it is the path of least resistance. SO, the "water" in the remaining lines also drains (loss of pressure or voltage) to help supply the need at the starter. Adding another "water tower" to the battery or simply powering up the coil alone, will replace the loss of "water" needed at the coil.

Now the main system, even if it needs more pressure, will not be able to draw enough through the little wire (attached to the coil via a second battery) to help the starter because it's just too small. Is it possible to overload that circuit.... in theory, yes. But only if the cranking battery is dead, or not present. Even then, it is more likely that because the starters demand is so great, it would be like hooking a garden hose to a fire hose and trying to use it. The starter would just groan, or the solenoid click from lack of "flow". Now, if you continued to hold the starter engaged with only the small wires attached and back feeding from another battery, yeah.... they would likely start to get hot. But it's not going to be immediate. It's not a dead short, it's just an overload on not a big enough line. Big difference. Takes time to heat up from overload. Dead short is like a light bulb. INSTANT and maximum draw that gets hot NOW. Example: Failed v-regs on the old S/G systems will occasionally fail and once the starter is engaged, short to the armature and when you let off the key, the starter will continue to crank. Doesn't crank fast..... but still cranks. When I've had it fail, I was able to get a wrench and disconnect the battery before wires burned up. They got pretty warm, but didn't burn up. Simple repair of the v-reg or replacement and all was good.

Lets go back a bit:
On the older starting systems, there was a terminal on the starter solenoid marked with an "I". This was to be used for the ignition system. Just as I explained above, the older batteries were small, and the ignition system would lack adequate power to supply voltage to the ignition during cranking. All the electricity was "flowing" (like water) to the starter. The solution: Add a terminal at the solenoid where all the power was going, and run it directly (second wire) to the ignition coil. Since the power was flowing to the starter, they simply tapped into that source and fed the ignition. As a note, even if this tractor has an "I" terminal on the ignition, tapping it wouldn't help, as the simple truth is the sytem is so small, and the fact that the solenoid is so far away from the starter, it wouldn't make a difference. On the system I am describing, the solenoid was mounted to the starter, and coil generally not far away.

Does any of that make sense or help? :Unknown: