MF240 not charging

[dwaller]

I just bought a MF240 with a 232 loader not too long ago. The tractor starts and runs fine, but I'm having an odd issue where if I run any of the lights (headlights or flashers on the fenders), everything works great while the tractor is running, but the next time I go to start the tractor, the battery is dead. I put a full charge on the battery, using the lowest setting on my charger. After I let the battery rest, it was at 12.8v and I've been starting the tractor without issue ever since.

My feeling is that the alternator might be charging just enough to allow me to start the tractor, but if I use the lights, the alternator falls behind to the point that there isn't enough voltage to start the tractor the next time. I've used the lights twice, and had to jump the tractor each time afterward.

I did do some reading, and I tried to put a screwdriver on the backside of the alternator while the tractor was running to see if there was any magnetic pull, but there wasn't any. I used my (very limited) battery charger to check the voltage at the terminals of the battery while the tractor was running, and it measured 12.1v, which would indicate a lower level of charging than expected. For reference, I hooked the battery charger up to my old garden tractor while it was running, and voltage was measuring at 13.8v, which is more in line for what I would expect.

I also read that the oil pressure switch could cause issues, and that if that switch goes bad, it doesn't allow the alternator to charge the battery. Are there any tricks to testing this, or is it a cheap enough part that I should start here and work my way to the alternator if indeed that is what the problem is?

I should add, the RPM indicator and hour meter work, but neither the fuel gauge or the temp gauge works, which is why I'm leaning towards some sort of a switch being bad. Any suggestions are very much appreciated.

Thanks for any help.

 

[BigDog1956]

I just bought a MF240 with a 232 loader not too long ago. The tractor starts and runs fine, but I'm having an odd issue where if I run any of the lights (headlights or flashers on the fenders), everything works great while the tractor is running, but the next time I go to start the tractor, the battery is dead. I put a full charge on the battery, using the lowest setting on my charger. After I let the battery rest, it was at 12.8v and I've been starting the tractor without issue ever since.

My feeling is that the alternator might be charging just enough to allow me to start the tractor, but if I use the lights, the alternator falls behind to the point that there isn't enough voltage to start the tractor the next time. I've used the lights twice, and had to jump the tractor each time afterward.

I did do some reading, and I tried to put a screwdriver on the backside of the alternator while the tractor was running to see if there was any magnetic pull, but there wasn't any. I used my (very limited) battery charger to check the voltage at the terminals of the battery while the tractor was running, and it measured 12.1v, which would indicate a lower level of charging than expected. For reference, I hooked the battery charger up to my old garden tractor while it was running, and voltage was measuring at 13.8v, which is more in line for what I would expect.

I also read that the oil pressure switch could cause issues, and that if that switch goes bad, it doesn't allow the alternator to charge the battery. Are there any tricks to testing this, or is it a cheap enough part that I should start here and work my way to the alternator if indeed that is what the problem is?

I should add, the RPM indicator and hour meter work, but neither the fuel gauge or the temp gauge works, which is why I'm leaning towards some sort of a switch being bad. Any suggestions are very much appreciated.

Thanks for any help.

maybe disconnect battery-make sure it's fully charged (check volts w/meter)-leave overnight and recheck in morning, this will let you know it's holding a charge, maybe even run up too parts store have them lot test it, if all check's well then re-install and start tractor---w/meter see what volts are coming from battery post's (recharge), should be around 13volts? 13.8 is ok, if it's under 12.5 you alt is prob going south, but make sure battery ain't being goofy, a decent volt meter is a MUST own tool. HOW OLD IS BATTERY?????

 

[dwaller]

maybe disconnect battery-make sure it's fully charged (check volts w/meter)-leave overnight and recheck in morning, this will let you know it's holding a charge, maybe even run up too parts store have them lot test it, if all check's well then re-install and start tractor---w/meter see what volts are coming from battery post's (recharge), should be around 13volts? 13.8 is ok, if it's under 12.5 you alt is prob going south, but make sure battery ain't being goofy, a decent volt meter is a MUST own tool. HOW OLD IS BATTERY?????

Unknown as to how old the battery is. I'll be working out in the barn later today, I'll do what you said and disconnect and do a full charge, then let it rest overnight to see what voltage its sitting at. I did pick up a real multi-meter, so I'll use that to measure voltages this time instead of the cheapo battery charger. I can also check voltage from the battery terminal vs voltage on the cable and see if there is a difference of some sort.

Since I did a full charge on it the last time, I haven't had to jump it, and there have been a couple of mornings where it has been pretty chilly, and its taken two or three times of 10 second cranking to get it to start, with no sign of fatigue in the battery. Maybe I'll start it and turn on the lights to see if the charging voltage drops any.

Any ideas on the fuel and temp gauges not working? Is that just a common thing on older tractors, or is it possible to trace back to another part that would need to be replaced?

 

[BigDog1956]

Unknown as to how old the battery is. I'll be working out in the barn later today, I'll do what you said and disconnect and do a full charge, then let it rest overnight to see what voltage its sitting at. I did pick up a real multi-meter, so I'll use that to measure voltages this time instead of the cheapo battery charger. I can also check voltage from the battery terminal vs voltage on the cable and see if there is a difference of some sort.

Since I did a full charge on it the last time, I haven't had to jump it, and there have been a couple of mornings where it has been pretty chilly, and its taken two or three times of 10 second cranking to get it to start, with no sign of fatigue in the battery. Maybe I'll start it and turn on the lights to see if the charging voltage drops any.

Any ideas on the fuel and temp gauges not working? Is that just a common thing on older tractors, or is it possible to trace back to another part that would need to be replaced?

on gauges I would find wires to each and follow to gauge-see if gauge is getting power, if it is-then prob just need gauge, but could just be a old broke wire,connection.......

 

[dwaller]

Sorry it took me so long to update. I took a look at all the wiring and fuses, and everything looked good. I decided to order a new oil pressure switch (part number 3599307M1), since it seemed like too much of a coincidence that the gauges weren't working, and the battery wasn't charging, so I took a chance on the $11 part.

I finally put it in tonight, and immediately saw results. With the ignition switch turned to the on position, but the engine not started, the light bar on the top of the dash that indicates whether the battery is charging, or oil pressure is low displayed lights. Once the engine was started, the 'no charging' indicator displayed until I got the revs up to about 900. I then took my multimeter and tested the posts on the battery with the engine running, and it reported 14.6v. Success!

I then turned the flashers and headlights on and checked the voltage, and it was still reading 13.6v at the posts, so I wasn't discharging the battery any longer when running the lights. Also, the lights on the gauges lit up so that I could read them with the lights on the tractor switched on.

The fuel is still low, so I'm not sure if the gauge itself is working, but I'll check that the next time I fill it up. The temp gauge didn't really move either, so I'm thinking I should maybe change the temp sending switch out as well, but it also could be that we still only have temps in the high 40's. I'll keep an eye on that as well.

The biggest thing was getting the tractor charging again, which I did, the gauges are secondary to the goal at this point. Thanks for the suggestions, I'm sure I'll be back again as the tractor ages further.