If I could only get the little woman to park her car outside :bigthink: I'm sure she'll go for that this would be me If I even suggested it :bash:
You know these very well can I change the ignition module without pulling the motor?

1872 should have a Mag 18 in it. The Mag18 has an ignition module not a coil. It's mounted to the back of the engine under the blower housing. You get to pull the engine if it is in fact bad.

The engine will have to come out to change it.

I have a 782 with a M-18 in it.
I changed the coil/Ign module last summer and I didn't pull the engine.
IIRR, I removed the gas tank, firewall, rear fan shrouding bolts and kind of pushed it back and other things that were in the way to get to the coil on the head.
I put a .010 piece of metal over the magnets on the flywheel to properly space the coil assy away from flywheel.
and tightened things back up, it was not that bad of a job really.
I'm thinking the 1811 is similar?

You have not conclusively proven that the ignition module is bad. That is a lot of work to replace a part that may not be bad.

It may be as simple as low cranking speed. The small batteries used in these come in a variety of flavors from crap to pretty stout. I just replaced the battery in my 1872 due to cranking too slow to fire in the cold.

If you need a battery, the only number to look at is CCA (Cold Cranking Amps, measured at 0*F). The other number is just CA (Cranking Amps, measured at 32*F); no need to pay attention to both numbers.

Only look at the CCA number. There is no way to make that number high without making a better battery. Some crap batteries will not list the CCA; if they won't show it, you can bet it is low.

The best I found was at Advance Auto Parts, 340 CCA ("Lawn & Garden Pro"). The worst I found was also at Advance, 160 CCA. The price difference was substantial for a reason, it costs more to make a better battery.

With the 340 CCA battery, the cranking speed is substantially better. Also make sure your cables are in good shape and use dielectric grease on all connections to keep the corrosion away.

You can't troubleshoot it until it doesn't work again. The next time it won't fire, try some starting fluid. Often they are cranking too slow to fire on gasoline but will fire on ether. If it fires on ether but won't stay running on gas, you have a fuel delivery problem. If it fires on ether, stays running on gas, and never has a problem at any other time, it is probably just cranking too slow.

If it won't fire on ether and the cranking speed is reasonable, then it may be the ignition module. Check for spark immediately during this troubleshooting session before something changes, not the next day when conditions are different.

Get two spare plugs for checking for spark. The Kohler manual recommends using one of these two plugs gapped at 0.130" when you are checking for spark external to the engine to simulate combustion chamber conditions (compression). This is generally done by just removing a portion of the ground electrode of the test plug to create the large gap. (Measure to be sure of the gap.) Connect both test plugs to the plug wires (one with normal gap and one with the large gap) and ground the plug threads using large electric test clips wired to the engine ground. (Don't remove a plug from the engine or you will increase the cranking speed due to the lowered compression resistance, and you will be changing the conditions the engine is experiencing.) The Kohler manual does a good job of explaining this and has a diagram. The Kohler service manual is available here: http://www.kohlerengines.com/onlinec.../tp_2204_b.pdf

The Kohler manual has a second test using an ohmmeter that can give assurance of a module problem. If you are not getting spark, make sure you don't have the kill wire grounding accidentally. Unhooking it at the engine for the test is one way to troubleshoot this.

Ignition modules (magnetos) can be intermittent, but it won't stay that predictable. If it is really a problem, it will become more and more apparent.

Good troubleshooting is proving something is good or bad before you move on. Guessing and just replacing parts will make you crazy and poor! Good luck!

Good stuff Tom

Only thing I don't like is using starting fluid. I've seen too many bad results from it the hands of people that use too much. The fact that he got it started once it was warmed up a bit leads me to believe the battery may not have enough oomph or the connections are poor. I'd also add that the battery cables on most Cubs are too small to carry enough current in cold conditions. Had a 1210 that would not spin fast enough to get going on cold days. Replaced the cables with welder cable and a ground straight to the engine block, problem solved.

I agree that ether should be used in small doses, for troubleshooting or emergency use only. It takes very little to make an engine fire, just a half second squirt.

Based on everything I have seen in his history with this problem, my bet is also on the too slow of cranking speed. I outlined the spark check just to be sure if needed.

I also agree on the battery cables, Cub skimped here and larger is better. Dielectric grease on every electrical connection will keep them good. I put it on every wire before a crimp and in every terminal before connecting, including battery terminals.

The battery quality is a real issue too. Unless someone has read up on it they may not realize that the same physical size battery can vary so much in power.

Maybe pull the battery out, put it in a warm location on a charger all night and try it in the morning and see if it starts. It sounds to me like your battery is getting weak. I have a good ignition module I will ohm out for you to test yours and they also explain that in the manual.

Hey, if these things ran when we needed them they wouldn't be any fun.:biggrin2: Don't give up, we are here to help.

I kinda thought so thanks for the info Allen.
Great info guys! Thank you Tom for taking the time to type up that extensive explanation. At this point I'm going to take one thing at a time starting with the most logical step first based on what I'm seeing and reading and my past experiences. I had mentioned somewhere in the beginning that I felt the battery was doing a good job of turning the motor over plus it seams to have a pretty good reserve. When it does finally drag down because of a no start I put my booster on it and crank some more with out success so I believe I can probably rule out the battery or at least put it towards the bottom of the list of suspects. Sam The cables at this point because the battery seems to crank the motor over pretty good I will upgrade in the future but at this point because it does crank pretty good I'm going to put that towards the bottom of the list of suspects. I do like the idea of a better ground going right to the engine and may do that regardless.(I'm keeping in mind I may have to eat crow later on but I have to start somewhere). At the top of my list is to check the ignition module I have borrowed a spark tester from a fellow worker from the shop that will give me a accurate answer to whether or not the ing module is putting out enough spark (15000, I believe is what he said) so I'll see what happens tomorrow morning and then go from there. Oh and Oak I cant give up I've got to much wrapped up into here to stop now. It would also be nice to know what your ignition module ohms out to so I can bench test the one I have sitting here Thanks! George I'm going to look real hard at changing without pulling the motor in case I have to this is on a 1872 if you were able to do it on a 782 I surly should be able to do it on this one. I'll know if I need to change it tomorrow. Thanks for the info

I got out this morning to check spark with the spark tester and it looks really good so that says the ignition module is good I will read in the service manual to do further test but this tester is supposed to be cut and dry. While I was out I checked the cca of the battery its rated at 340 and as I mentioned has plenty of power to crank it over even when freezing . I'll keep looking I havnt given up yet. I'm wondering if I'm just plain flooding the thing? Although I'm not smelling gas, if I am its flooding way to easily next time it doesn't start I'm going to pull the plugs and check to see if their flooded.
I'm new to adding vidoes to youtube but if I did it right it you should be able to see the test under 1872 spark if you want to see how much spark I'm getting The spark test was done with it sitting in the garage over nighta at about 45 deg I drove it outside and after it sits overnight I will check again in the morning.

I ran into a flooding situation last spring on the 2072. The carb needle seat must have been pitted and would not stop the leaking untill i honed or polished the seat. U can check for this by looking down the intake riser under the air cleaner. After about 24 hours of sitting i would look down with a flashlight and see fuel laying down at the bottom. This did cause a real hard start. Good luck. Dave

As mentioned I did a spark test with the engine warm (sat inside garage) and with the spark tester there was plenty of spark then the next morning I tried a cold (sat outside) test I with the tester there was no spark so I disconnected the white wire to make sure the ignition wasn't grounding the coil and with the wire disconnected there still was no spark so while doing this I noticed a oil sentry sensor sticker on the motor but I don't see it on the print so at this point I'm trying to figure if there is one and if there is is that somehow failing when cold? If not then the ONLY thing left is the ing module.
After finding the oil sentry switch on a schematic
1- It cant be the problem because the white wire to the coil is disconnected
2- Theres not a second wire running to it so there cant be one.

Ok here it is after doing some final checks for a bad ignition module, by removing the ground wire (white) and turning it over in cold weather there is no spark . The ONLY thing it can be is a bad ignition module as was mentioned buy OlGeorge they sometimes wont produce in the cold ( this is me eating crow) I had to go through the process of proving or disproving this because to change it its a pretty big job. So when I feel I want to take the time I'll change it until then it will just have to stay in the warm garage that way it will start when needed to plow.

Or use something like this aimed under the tractor for a while before you want to start it.
http://www.amazon.com/Mr-Heater-Prop.../dp/B0000C6E3H

:bigthink:

Did it start when you reduced the plug gap? or start easier? if so leave the close plug gap.
And use a closed throrttle or just open it slightly, as it requires less voltage to fire the plugs under compression.
I've seen it many times.
Sometimes you have to throw the book away and adjust to conditions.
In the warmer weather you can change the unit,as you planned.
It has been my finding aftermarket units work just as good,--- but only in warmer weather so it is your call.

When you added an electric fuel pump did you remove the mechanical one?

This is a year old thread...... would have been better to just ask the question on the forum (digging up old threads sometimes won't get you a response).

If you put an electric FP on, yes, you should take off the old mechanical. Personally..... I prefer the mechanical. No need for all the extra wiring, and the cost is about the same.

No Spark When Cold Update
 

This is a update to an older post but it will give the people who are interested some background. I finally got the time and ambition to tear into the i872 earlier this winter to figure out what was going on with the spark. What I found amazed me that the m18 was running at all and the old girl wasn't spitting parts as she ran. My first findings were there was only one engine bolt holding the engine to the engine plate, The drive shaft was worn on both ends and of course the bearings were both shot. I preceded to pull the motor, I removed the engine shrouds and found one of the head bolts were backed out and there were enough loose head bolts that I was surprised there was not a blown head gasket. On to the fly wheel cover, I removed it and there was the problem plain as day. The gap for the ignition module was at least 1/8 to 1/4 inch gap on one side and 1/2 to 3/4 inch on the other. What was even more puzzling was the fact the bolts were tight and there no signs the module had been hit and forced to that position who knows how it ended up that way. I reset the gap, checked the spark it was a good blue. I did some degreasing in the engine bay made a couple of notches on the engine mounting plate to get around a few tight spots I then set the motor in. I ordered a new drive shaft and bearings, new rag joints, new center lock nuts put her back together. I greased all grease zerts and lubricated all the moving linkages and reinstalled the oem fuel pump and the new engine shrouds. Wala she starts and runs like a new tractor. It sometime surprises me I just tap the key and she fires up what a good ol girl.

This is the fuel pump I have used with no issues. I tried to find them cheaper but had no luck so I just buy them here when I need one.

http://www.kirkengines.com/index.php...tronicFuelPump

Thanks I'll keep that link in mind for the future