lawn tractor not charging

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barbee6043

barbee6043

barbee 6043
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I don't want to hijack RRR's mower thread so I will ask this here! Since it is so hard to get up and down, and I have no love for small engine stuff, I take my mowers to a small engine shop, and so far I have not found one worth *** and save myself when I have to work on my old cars. Latest issue is the 7 year old Cub Cadet and charging. The last "mechanic" replaced the "what you all it" that charges the system, but it ain't working. I called CC tech twice, they sent me a electrical diagram that I can not read and the "tech" knows where to put in the gas and thats it.

Whats up? Bad ground? New part bad? Should not the charging system be really simple?????
 
IDK about the Cub specifically, but I have worked on hundreds if not thousands of small engines and yes the charging systems are really simple.
Usually there is a small coil mounted under the flywheel, and flying magnets on the flywheel. There are no moving parts to this so it rarely makes trouble.
This electrical generating coil creates A/C so it has to be converted to D/C, then regulated down to a voltage that won't boil your battery. All that happens inside a tiny box bolted onto the chassis, usually somewhere under or nearly under the seat, or directly bolted to the engine.
Thus, the system consists of these components;
the coil and magnets, and
the regulator, and
the battery itself.
The system works almost exactly like the one in your car.
The first thing you gotta do is charge the battery and load test it to make sure it is actually serviceable.
The second thing is to disconnect the regulator and check the output of the"alternator". You have to test for A/C, and If you get anything over 14 volts at idle, then the darn thing is working. If less than 12 well then, she's iffy, rev it up and my guess is that it might output over 30 volts at some higher rpm.
Once the voltage generator is proved to be working, it's on to the regulator.
Again, IDK specifically about the Cub;
But from my experience the regulators on most of these riders are not much more than A/C to D/C convertors; A/C goes in and D/C comes out and the battery itself is the regulator, in as much as whatever voltage comes out of that thing, it all goes into the battery. The power coming out of that generating coil is so small, that it can't hurt the battery.
So if you get D/C coming out of the regulator, it's probably good...... BUT....If you get ANY A/C at all coming out, she is broke.
This type of regulator probably does not need a ground. The coil under the flywheel is grounded to either the flywheel, to the crank, to the engine block, or directly to the engine block via a second wire, then to the battery negative via the cable.. The battery should also be grounded to the chassis so the lights, etcetera, can work. There is an off chance that the case of the regulator needs grounding.

BTW
This system cannot charge a dead battery. It only makes enough power to maintain it.
 
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Are you sure it's not charging, maybe a bad battery also some engines have a compression release that if it fails the starter won't be able to turn the engine over.
 
AFAIK the Cubs have an automatic decompressor bolted to the camshaft, and yes, they do fail. The test for this is a compression test. If it's working, the compression tester will read usually, around 60psi. If it's broke, the pressure may be over 100psi, and like bschief says, the starter may not be able to crank thru the compression stroke. But it will try and the compression will stall the starter and when you release the key, the compression will kick the flywheel in reverse pretty hard.
If the starter cranks thru at least on compression cycle, I would suppose that the decompressor is fine.
To replace the decompressor on a flathead, the engine has to be completely torn down, and usually, the cam has to be replaced, and the valve lash adjusted.
 
What voltage do you measure across the battery with the engine running...and with it off?
 
There is almost always a very important difference between these small engine systems and an auto system. Generally, there is no field, and so the alternator (flywheel magnets) put out full blast. How to regulate? The regulator is called a "shunt" regulator, and what that means is, it basically shorts out part of the output to keep it down to a reasonable voltage.

Without a diagram, I cannot advice, but if the regulator is separate from the rectifier assembly, you should be able to disconnect the regulator and see full output. Other than a bad alternator stator or rectifier, there may be an inline fuse. Other than that, the usual--bad connections, etc.
 
That year cub most likely has a 23hp Kohler engine on it. If you didn't hear a bunch of grinding going on the the flywheel magnets probably haven't fallen off yet. On me side of the blower cover there should be a voltage regulator. It is screwed into the plastic cover and should have a silver ground strap that ties the regulator to metal for a ground. The screw loosens up and no longer provides a ground so the regulator doesn't work. I bet if you take care of that it will charge again
 
I bought a brand new Simplicity a few years ago. It died all the time. They found that the magnets on the flywheel were not magnetized. Replaced the flywheel and its been perfect ever since.
 
diymirage said:
What voltage do you measure across the battery with the engine running...and with it off?
Click to expand...
I fully chaarged the month old battery after wife put out fertilizer for a couple hours. 12.8 charged. This AM went to start it and would not start, turning over freely. Gave it a shot of carb cleaner and away it went. Like said, 12.8 fully charged NOT running, then cheked it running and it dropped to about 12.6.
She ran it 30 minutes probably and it showed 12.54 AND then shut off off it read 12.6.

LIke said, it is 7 years old and our grass is nore and than grass and when dry it make LOTSof dust I clean the oil bath filter but I doubt it keeps out the dsut that good. It does not smke an just recently the oil lever was down some. Compression may be suffering some.
 
toplscuda said:
That year cub most likely has a 23hp Kohler engine on it. If you didn't hear a bunch of grinding going on the the flywheel magnets probably haven't fallen off yet. On me side of the blower cover there should be a voltage regulator. It is screwed into the plastic cover and should have a silver ground strap that ties the regulator to metal for a ground. The screw loosens up and no longer provides a ground so the regulator doesn't work. I bet if you take care of that it will charge again
Click to expand...
Not sure where it is on mine, BUT I bet you could be correct. Cub Cadet is worthless to get any diagrams from. But so is my old computer.
 
I know that I have a different model, but my sears stopped charging. It was a diode on one of the wires. Mower guy checked it one way, and it was fine. Checked another, and it was bad. Been charging ever since. You might want to check for this if the other suggestions don't pan out.
 
It should look like this. You can see the factory ground strap at the bottom and the green one I ran to the block
IMG_1714.jpg
 
Thanks all, I will persevere on!!!!

I have an old commerccial Z turn that is my back up that also needs a BACK UP! It is another STORY!!!!!
 
It's not a "cub" problem. What brand of engine? Briggs Kohler or Kawasaki? They're who designed supplies and built anything directly connected to the engine
 
Well many companies used that same Kohler in other brands. Even MTD itself (who's owned cub since 1981) has other brands that probably use that same engine. You need to be looking to Kohler for service info.
That said I've worked on a few Kohler's with charging issues....
 
volaredon said:
Well many companies used that same Kohler in other brands. Even MTD itself (who's owned cub since 1981) has other brands that probably use that same engine. You need to be looking to Kohler for service info.
That said I've worked on a few Kohler's with charging issues....
Click to expand...
Will do.
 
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