MF 175 diesel

[Rls731]

Im having a problem with my MF-175 diesel. I posted earlier about it not charging and was told to check the oil pressure switch. I discovered the wire going from the oil pressure gauge to the regulator was bare and touching the steering column. I replace the wire with new. I also notice the fuse under the dash was blown. I eliminated the fuse temporarily and connected the 2 wires. Now when I turn the ignition switch nothing happens. Nothing. I made sure both transmission levers are in neutral. I've also replaced the voltage regulator. Still nothing. I jumped the starter and it turns over but when on turn the ignition switch nothing happens. Shouldn't I hear something fron the the system to the oil pressure switch when the ignition is turned ? I've even disconnected the line at the oil pressure switch and nothing comes out when I turn the ignition switch. Im at a loss. Please help

 

[DanielW]

First check would be checking voltage at the solenoid excitation wire when turning the key to the start position (obviously disconnected and carefully, so it doesn't fire off and run you over when checking).

 

[Jim.ME]

The engine has to be running to send oil up the line to the oil pressure gauge and oil pressure switch.

Oil pressure operates that switch just like you operate a toggle switch with a lever.

 

[Jim.ME]

Your MF 175 diesel did not come with an ignition switch. It should have a key type start switch which only is used to engage the starter. This circuit should be seen on the wiring diagram in your Operator's Manual. The oil pressure switch turns on the fuel gauge and charging, after oil pressure from the running engine closes the contacts in the oil pressure switch.

 

[Jim.ME]

Wiggle the Hi-start-low lever a bit in start (neutral) to safety switch might be out of adjustment

 

[Harry in Ky]

FIRST thing to check is do you have battery voltage at the key/start switch? One side of the switch should be battery live regardless of the wiring to and from the oil pressure switch. Since had wiring issues elsewhere and have disturbed things to some degree you may have affected power to th key switch.

 

[Rls731]

These are pictures of the ignition switch. It appears to be original

 

[Harry in Ky]

We know what they look like. Is there power there?

 

[Jim.ME]

These are pictures of the ignition switch. It appears to be original

It is a starter switch. It should have power all the time on one wire (the green one I believe) and the other wire carries power to the neutral safety switch to energize the starter when the switch is turned to start. Original or not means nothing, Test for power.

Have you looked at the wiring diagram so you can see where to test for power?

 

[Rls731]

We know what they look like. Is there power there?

Someone here told me they only came with key switches. I was just showing that mine isn't

 

[Jim.ME]

Someone here told me they only came with key switches. I was just showing that mine isn't

I have a couple of Masseys with these keyed start switches. That is a key type start switch, period. Turn the knob vertical, remove it and you will see it is a key that can be removed preventing the normal method of engaging the starter.

It is different than a keyed ignition switch ignition switch used on a gas engine or diesel with an electric fuel shutoff.

Have you done any testing for power yet?

 

[Rls731]

Yes I've tested for power and there's power all the was through the neural switch to the solenoid. But I don't know where the brown wire goes to. Maybe to the alternator or other side of the solenoid . I won't be able to check it til Monday

 

[Jim.ME]

Brown, tan, gray? The problem with just saying a color to chase is that colors can fade over time, and you cannot be 100% certain the function of that color wire is the same as the one on the drawing. Colors were sometimes changed during production. Finding both ends of a wire is key.

If you have power through the start switch and neutral safety switch to the solenoid, it sounds like a battery cable, solenoid, or starter issue, if it will not crank. Be sure the tractor is in neutral and use a jumper wire to make contact between the battery cable post and the start terminal of the solenoid. If it cranks the starter, you may have a switch or connection that shows voltage but will not handle current enough to energize the solenoid.

Do you know what alternator your tractor has on it? Is it a Delco Remy with a separate external voltage regulator (10DN) or a newer one or three wire type Delco(10SI)?

Other than the battery cable post wires and motor connection, a diesel should only have the wire from the neutral start switch on the solenoid start terminal, the other small terminal should not have anything on it. That terminal is used on a gas engine to provide a resistor bypass for the ignition system during starting.

 

[Rls731]

It's the remy delco alternator with the separate voltage regulator

 

[Rls731]

This is the alternator

 

[Jim.ME]

Looks like bad cables and wires at the solenoid.

Your alternator pictures won't enlarge. Can you get a better picture of the wire connection points on the back of the 10DN alternator? I can't tell if all points have a wire on them as a point to start checking.

 

[gbsmith]

have a look at this from a previous thread it is for the 175 diesel like yours

 

[Jim.ME]

have a look at this from a previous thread it is for the 175 diesel like yours View attachment 150907

In another thread he posted he has the parts and Operator's manuals. If he has the correct MF 175 operator's manual, as he posted, he should have the actual MF 175 wiring diagram in his Operators manual.

 

[Rls731]

Thank you. I do have the parts and operators manual. I will get better pictures of the alternator. I will not be able to check all these items til Tuesday. Thank you to all of your help. I plan to clean all the connections and replace some connectors with new ones. I just want to get the key start operating again and the replace the wiring harness properly and replace all the gauges in spring

 

[Rls731]

I've made changes to the wiring to match the wiring diagram. The tractor now turn over and starts. The battery is not charging. There is humming coming for the voltage regulator for about 5 seconds after the tractor is shut off. The voltage regulator has already been changed.