MF 135 Electrical issue

[jjlanotte]

So I went to start up my MF135 Perkins Gas for the first time this year and Im not getting much from it. I hear a single click from the 12v regulator and thats it. No movement of the instrument gauges. Does not attempt to turn over at all. So far I've tested and replaced, for good measure, the nuetral safety switch. Both were in good working order altho the old one was pretty nasty. The battery is only a year old and it tests fine, its fully charged. I get voltage to the ignition coil. And thats where Im at right now. Any suggestions?

 

[Industrial Toys]

Does it have an old style relay operated regulator?

I hate to start touching stuff that is fine, only to compromise that connection for future trouble.

Of course, I would start at the battery connections. In neutral, did you try jumping the starter? That would tell you, battery is OK, and battery connections, starter connections, starter and solenoid.

12 volts is the worlds worst vehicle voltage, well except for 6 volts. A connection may allow small current and show good on a meter but not allow large currents.

 

[jjlanotte]

It has what I am assuming is the original 12v regulator as it is still riveted in to the support bracket. I have a new one that came today but didn't get a chance to mess with it. Im not sure what you mean by jumping the starter, can you elaborate on how to do that?

 

[Industrial Toys]

I almost don't want to, because it can be dangerous. I know a guy that starts his old ALLIS twenty times a day like that.

Anyway, using a wrench or big screwdriver (that isn't valuable), you short the positive lead coming from the battery on the starter to the starter terminal, (the link going from the solenoid to the starter motor proper).

A good way to get run over if the tractor is in gear.

 

[jjlanotte]

Eh, Im good with not dying. I'd probably just continue to do that instead of fixing the actual issue. Any chance the 12v regulator being bad would give me all these symptoms? Or advice on what to trouble shoot next?

 

[Industrial Toys]

How competant are you? The importance of Good connections cannot be stressed enough. And more than that, are Good connections that will continue to be good. Anyone can make a tractor start or brake lights work for the moment and even give themselves the high five!.

I don't know much about old school regulators. But I'm guessing no, it would just have an effect on the charging, not charging or over charging of your battery.

 

[jjlanotte]

I'm fairly competent. I'm an aircraft mechanic, not a tractor mechanic . I do have all the manuals/IPC for the thing as well. I'm just not much of a spark chaser I usually do engine work. I've been through this tractor a lot since I've owned it. Stopped every leak, got her running like a top. I just haven't really had many electrical issues.

 

[Industrial Toys]

Man I have a leak for you. Something I have been putting off tackling this week. You come fix my hydraulic leak and I will fix your electrical. Can you get good air plane ride rates? Or just borrow one like that other mechanic a while ago. But return it, unscratched. Maybe a "test" flight. lol

 

[Industrial Toys]

Basically, the B+ has to go to the ignition switch, then starter portion of that or seperate switch and then to the strater solenoid (through the safety switches at some point).

 

[jjlanotte]

Ha, I've ripped out my PTO to replace all its bearings and everything when it was leaking, it worked, so i could probably fix yours. I work on corporate jets, will it be ok to send one of those?

 

[Industrial Toys]

Daaaam, the machine I would use to clear a landing strip is the one that's down. How many feet do you need?

Actually, a neighbor a mile down the road has a strip, and he too is an a/c mechanic. Never met the guy though.

 

[jjlanotte]

Probably 3500 feet, paved.

 

[Industrial Toys]

ooooh!

Greyhound still come through town?

 

[jjlanotte]

Lol, nope

 

[WranglerX]

I'm fairly competent. I'm an aircraft mechanic, not a tractor mechanic . I do have all the manuals/IPC for the thing as well. I'm just not much of a spark chaser I usually do engine work. I've been through this tractor a lot since I've owned it. Stopped every leak, got her running like a top. I just haven't really had many electrical issues.

Just think of tractor as airframe without wings.... Starting circuits are all very similar.... Power from battery to a solenoid, power from ignition switch to coil, put ign switch over to start (or push button), engages solenoid and starter spins motor, if spark and fuel and timed corrector it should start....

Only thing the ever threw me was ignition switch on ex-wifes VW... In "start" position switch was defective and didn't supply voltage to coil...

Dale

 

[jjlanotte]

Came here to post the found problem. I took my starter off to test it and the solenoid on a separate 12v source. Upon taking it off the disconnected +battery lead came with it. Starter tested good. Upon visual inspection I noticed the battery cable was pretty severely corroded. I was always getting voltage but never enough to budge the starter. Upon making a new cable it fired right up.

 

[Industrial Toys]

I have never done it, but putting a load tester on at the starter will check for the connections and cable to the starter. A high impedence DVM will give you readings that are misleading.

Good Job.

 

[lpakiz]

Yep, thats a downside of a digital volt meter. It will show full voltage thru a damp piece of hair, but that wouldn't be enough to light up a fireflys butt.
I use a tail light bulb, salvaged from an old vehicle. Outfit it with a couple small alligator clips and you're set.
Another way to overcome these limitations is to attach the tester, THEN activate the circuit and see if the voltage stays almost constant. You want to measure the voltage UNDER LOAD to determine if the connection is good.
Another redneck method to find a bad connection is to activate your circuit for 10-20 seconds, then go around and feel for heat. A bad connection will generate heat if the load is adequate.