Oil pressure switch

[Eugene]

Remove the side panel covering the oil pressure switch. Multimeter, Ohms position, Ohm/continuity check the switch with engine off and not running for several minutes. Start tractor, wait for 20-30 seconds, then Ohm/continuity check the switch again. This is a check to see if the switch is functioning - functioning properly.

My thought is that you will have to trace the wiring in the starter circuit to find the fault.

[Ojgrsoi]

I did exactly what Mozer & Larry suggested on my 184. Here are some pics.

Notice the Tee added so that I can keep the idiot light functional. I didn't want to punch new holes in my 184 so I used one of the existing holes to route a hard line to the gauge. There are probably more elegant ways to accomplish this, but using 1/8" brass was much more substantial than the tiny little lines most gauges use.
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Here is a view from the front of the tractor. I had to cut off the mounting bolt of the gauge after threading on the nut. If I'd do it again, I would have used longer pipes so I didn't have to cut the mounting bolt. The mounting plate for the gauges is just a flat piece of steel with 2" holes punched. I used existing holes and new bolts, nuts, and lock washers to mount the plate.
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Nice!

[mozer71]

Yes. Eugene explained it. I would just Start and light would blink a few seconds and when it went out, the engine started. I thought I got lucky but didn't know how that pressure switch worked. Pretty cool but I still want a parallel gauge. In acquiring this gauge, make sure it isn't high pressure readings. It has to be accurate between 5- 30 psi. So it is a more sensitive type gauge.

[Ojgrsoi]

This discussion is important. The base 154's just have a light which blinks , showing low oil pressure. When it goes out, that is supposed to be proper pressure but how would I know? I need a gauge telling me what is actual pressure. Mine is getting old and when put to the tasks, before a light blinks, I should know the oil pressure.

What makes the light blink?

[Eugene]

What makes the light blink?

The light bulb.

The numbered series did not use a flasher for the oil Tellite. The bulb used had a built in blinker and was a #257 bulb. Bulbs with built in blinkers were more common years ago but may be hard to find in 2018. Other bulbs or LED lights will work but will not blink.

Interesting. I looked and the #257 do show up on some sites for older vehicles. On one site they are listed as a a Ford Pickup Interior Light Bulb for 1956-1977. And for $2.95 I put in a different bulb #1895. Seems to fit fine. I will see how long it lasts.

[Saucymynx]

Well, the mystery continues. I replaced the oil pressure switch, and the dash light for good measure. The good news is that the dash light now works. When I turn the key on the red light comes on briefly and then goes off after a few minutes of cranking. So far so good. However, the tractor still does not start with the key in the cranking position – only when I release it to the run position. Same as before. In addition to the new pressure switch – light, I have replaced the coil, the ignition switch, and the headlight switch. I have followed the wiring diagram very closely and everything looks to be wired correctly. I am out of ideas. I can certainly live with it the way it is, but it bugs me that it’s not right. At least in all my efforts I have traced down the problems with my headlights and tail lights and they are all working fine now

[outdoors4evr]

Glad to see that you have fixed so many nuisance issues on your 184! Glad the headlights and now the oil pressure light are working!
It definitely would drive me crazy to deal with the ignition working that way as well.
So... I think you should put a voltmeter or a test light on the coil to do some checking. Put one lead on the coil and the other on the battery ground. Set the voltmeter to measure volts. Turn the key on to the first position (run). You should see 6-12v on the coil lead. Turn the key further to the crank position. You should still see 6-12v on the coil lead.
My wild guess is that you see the voltage drop below the point where the coil can create a spark or drop all the way to zero.

If the voltage just drops below the 6V necessary for the coil to create a spark, then you might have a weak battery or failing battery cables. Check the ground. Basically, the starter kicks in and spins the engine, but while doing this, it draws a lot of amperage from the battery and the battery voltage drops. When you release the key, the starter quits demanding amperage and the battery voltage goes back to 12v which is high enough to energize the coil. Look for battery cables that are worn or corroded, a failing battery, or a shorted starter winding that is drawing way too much juice to do the job.

If it drops to zero volts, then you have an ignition switch that doesn't keep the coil energized while the starter is cranking.

[Jim Becker]

. . . I think you should put a voltmeter or a test light on the coil to do some checking. Put one lead on the coil and the other on the battery ground. Set the voltmeter to measure volts. Turn the key on to the first position (run). You should see 6-12v on the coil lead. Turn the key further to the crank position. You should still see 6-12v on the coil lead.
My wild guess is that you see the voltage drop below the point where the coil can create a spark or drop all the way to zero. . . .

I recommend using a volt meter over a test light. In this case, you may be dealing with partial voltage loss that may not be obvious from a test light.

If you see voltage drop at the coil, here is the next test I would try to narrow down the problem:

Connect a volt meter from the + battery terminal to the starter side terminal of the magnetic switch. Ignition off it should show 12 volts. Ignition on it should still show 12 volts. Turn the ignition switch to the "start" position and the voltage should drop to very near zero. If it does not, you have a problem in the battery cable, the cable connections or the magnetic switch. Failure of the test outdoors4evr described would include the cable and connections in the possible problems but not indicate a problem with the magnetic switch.

By the way, I think I noticed an error in the wiring diagram posted above. The diagram shows a wire from the battery (+) side of the ammeter to a connector, but no wire out of the other side of the connector. Shouldn't it have a wire from the connector to the battery side lug of the magnetic switch? This would not cause the current problem.

[Larry B]

Yes there is a wire missing in the schematic.
Like others have said you need to see if you have voltage at the coil when cranking. If the battery has enough capacity to crank the engine it will fire the ignition.
Connect one lead of a voltmeter to the terminal of the coil not going to the distributor. Connect the other lead to ground. At key on you should have battery voltage. Turn key ro start and crank engine. You should still have battery voltage. If goes to zero volts look for ignition switch problem. If voltage drops below battery voltage at cranking but not zero something else the problem.

[Eugene]

Yes there is a wire missing in the schematic.

The wiring diagram in my service manual shows the missing wire as well as a starter/generator and voltage regulator. Parts book for the tractor shows both the alternator and the starter/generator.

When you finish the electrical testing previously described, ohm out/continuity check the ignition switch. With the ignition switch in the start mode, there has to be continuity between switch lugs for the starter and ignition.

[mozer71]

HOW do i start here. The clutch pedal has to be down maybe the brake too. Great advise and read every word. You guys are so great our number series tractors may live beyond our time. I never thought about that.

[mozer71]

Whooofff is the word instead of F word .

[Larry B]

You don't need to depress the brake pedal. There is no inhibit switch on the brake. In fact you probably don't need to press the clutch pedal. Connect the voltmeter to the coil and turn to key to ON. Should have battery voltage. Turn key to start position. Should still have battery voltage. If you want to check while cranking most meter leads are long enough to clip onto coil and set on engine cowl while sitting in the seat and trying to start and read the meter.

[mozer71]

I'm Thankful for the descriptions of the starting circuity. This is super information which applies to many tractors and older automobiles. If I have anything to offer, it would be the VOM. Use a cheap digital at first, not your Dad's prized analog meter. These checks can blow the d'arsenvile (SP) movement right out of their jewels.

[outdoors4evr]

In fact you probably don't need to press the clutch pedal.

Numbered series tractors have a safety switch on the clutch petal. Tractor won't crank unless the clutch is depressed.