MF 175 Ignition and Charging

[bigtom63]

I have a problem with the charging system. I replaced the alternator on my 175 on advice it was not charging anymore. When battery charged it starts and runs maybe 4 times then starter gets stuck engaged. Get it un struck then charge the battery it goes on another 4 cycles. I also replaced the ignition switch thinking it may be sticking but after replacement the tractor starts with key but will not shut off by key. NEED SOME ADVICE where to go next??

 

[RAB]

Get some better advice before laying out hard-earned cash. The alternator might only have needed new field brushes, or from the post, possibly it was not getting any excitation field current to set it charging and is still not. But there again, I have no idea of what alternator you may or may not have.

There is a reason for the starter to get stuck engaged. Either starter motor is at fault or flywheel ring gear is burred (starter will use only a few places on the ring gear for engagement).

I take it that the alternator still not charging? If not, find out why not (excitation, broken or corroded wire, forgot to replace fan belt. Ignition switch - is the new one a direct replacement for the old one? May have different connections or you have reconnected it wrong.

Where to go next?

Sorting charge from alternator might be the best place.

Explain how long these '4 runs' are - like 4 hours, or more, at a time over a week or more, or 4 starts in 5 minutes.

If it is 4 starts in quick succession suspect the battery is short on capacity (so check it out).

Check out the starter and starter ring gear.

Replace the perfectly good(?) switch or sort out the connections on the new one.

Should be no problem then.

RAB

 

[Anonymous-0]

Its not wired right. When it runs on, its because the alternator regulator is connected to the ignition circuit and when running feeds power back to the ignition circuit. Needs a series resistor, lamp, or diode to prevent that feedback.

Gerald J.

 

[bigtom63]

Yes should have gotten better advice but stuck now. I did not put on a new belt when I changed the alternator. The new ignition swith is the same as the old one and I labled the wires and they are connected the same. The 4 runs could be say about 2-3 hours each but if we use the lights at all then the run could be only once. When we shut it down then we have to rock the tractor in gear to disengage the starter before we connect the battery charger. I am new to this so what is the excitation you speak of and how would I check for that current. I will inspect the wires when I get home tonight to see if some are broken or corroded. Maybe I just need to replace all of them one at a time? Also how do I check the battery for capacity I did notice last night while charging it sounded like the battery was boiling during the charge on 12V 30 Amp charge. Any more help is greatly appreciated.

 

[bigtom63]

WOuld understand that but this just started this past year. I bought this tractor about 3 years ago and it worked fine for about 2 years. I wonder if maybe a wire is broken somewhere in the loop?

 

[souNdguy]

Sounds like the alternator is not charging or not hooked up correctly.

If the #1 wire is not hooke dup, the alternator may not charge / excite.

If the charge stud is not hooke dup.. it won't charge.. etc.

Verify that the switch is good and does in fact shut the tractor off.

Have the alt checked at an automotive shop.. many do this for free.

If it is a gm-delco 10si alternator, #2 post to charge stud, and #1 post to key 'on' thru a diode or a marker lamp. If using a diode, marked side towards alternator..


Soundguy

 

[Anonymous-0]

More likely diode shorted. If there was a diode before.

Gerald J.