Old MTD

[Carl]

Had lots of trouble with the old MTD last fall. Didn't want to start. Found that it was related to my stupidity. Fixed that problem but it still wouldn't start when the weather got cold. So I fixed it I bought a NH TC24d and used it to move the snow around.

Just tried to start the MTD this afternoon. Suprise it started right up. That is with the gas setting in it since last December. Just charged the battery, and about 5 turns over and it fired right up!

Have question. Mine has a 12 volt generator that is used as a generator, and also as the starter motor. It also has the old contact type voltage regulator. The question is: I measured the battery voltage while the tractor was running at about 1/3 throttle and it was 13.5 volts. Is this about what I should expect?

[sixchows]

Carl
It has a starter/generator? Check the library there is a manual there on adjusting delco-remy regulators. I think 13.5 is fine. I also have some pages on the delco-remy starter/generator in my bolens. I think the info would be pretty much generic. I can get them to sj for posting in the library.

The cold weather starting problem might just be thick oil. Did you try 5W-30 or 10W-30?

[Carl]

I started out with straight 30 weight. Changed to 10W30 when the weather got cold. 10W30 is all that I ever used in it. My battery wasn't holding a good charge so I blamed the not starting on that. I will check out the library. See if it says anything about the charging voltage. I think that the battery went bad while it was sitting for almost a year.

[sixchows]

Could just be the battery, but sometimes the oil being thicker in the cold causes enough extra resistance to prevent the engine from starting normally.
You could try useing a heater to warm it up before trying to start it. Is it inside a shed, garage, or outside?

[Carl]

I guess that John-in-ga's motto applies, "it worked til I fixed it"! But I'm not even sure about that.

Received the Bolen's Delco Remy starter/generator page, and the regulator instructions. It may have been charging a little, but now it definitely isn't. When I replaced the hydrostatic drive this spring, I had to take the tractor all apart to get the engine moved forward enough so that the drive shaft could be removed. Which meant that most of the wiring had to be removed.

So when I looked at the regulator picture, and explaination of how it works I figured that I had hooked the wires to the regulator wrong. So I changed them. Now it really puts out zip. Finally took the regulator off, and discovered that the terminals are different than the one in the library. So rewired the regulator as it should be wired. Also did the voltage checks on the generator. It is not generating. Took the generator apart. Will clean all the brush particles out of it and check the resistance to ground. Tomorrow I will also pop the cover off the regulator to see if the contacts are pulling in. I have a regulated power supply so it should be a help to me.

That is the latest on the little critter. :00000060:

[Carl]

I completely disassenbled the generator this morning. Cleaned it all up. Repacked the bearings. Checked for shorts between field windings and ground - -ok. Checked continuity of both field windings - - ok. Figured that the brushes must be making contact because it will crank.

Took the regulator apart. It was clean inside. Neither of the contacts were burned, pitted, or dirty. All the coils had continuity. None of the coils were shorted to ground. So remounted it. Hooked up the wires. And - - nothing! :fing20:

Took the generator apart again. Rechecked all the coils. Cleaned the commutator. Checked all the coil connections for continuity. Cleaned the brushes. Put it back together. Reinstalled it. Polarized it. Cranked the tractor up and - - nothing. Checked the output at the generator at half throttle -1.5 to - 2 volts. Polarized it again. + 2 to 3 volts. Grounded the field like the regulator manual says and it lugged the engine. Removed the ground and same. Shut the tractor off and reread the manual to see if I had missed anything. Started the tractor and it was putting out - 2 volts again? :00000060: How can it reverse the voltage output when nothing is disconnected from it?

Tomorrow I will have to take the regulator apart again.

It has two field coils. One with heavy wire in series with the armature. This field is used for the starter. The other field coil is wound with smaller wire and it goes to the field terminal of the generator. This field coil is energized by the armature output and grounded through the regulator coils, and a resistor. :bonk:

Well tomorrow is another day. Good thing that I have the NH to fall back on :bump9:

[Carl]

After finding all my mistakes and wrong assumptions, and repairing the damage caused by those mistakes and assumptions it works! :banghead3

First assumption: I figured that since it would crank that the generator/starter was alright.

Second assumption: Since the regulator was clean I figured that all was okay with it.

Third assumption: I figured that since when the regulator was hooked up wrong yesterday, and no damage, that it was still okay.

Forth assumption: That all manufacturers would use the same color code for wiring.

I had disassembled the generator yesterday. Completely, then I decided to clean the communator and the brushes just to make sure. Resistance checks proved that everything was in order. Resistance checks of armature to ground while rotating the armature proved the brush contacts. Generator ok. That left the regulator.

This morning I resistance checked all the wiring from the battery connector to the regulator and from the regulator to the generator. Discovered that I still had wired wrong to the regulator. Now I know why pilots go through the check list the way they do. Had I done that the regulator would have been wired correctly. Put it all back together and it still wouldn't charge.

Took the regulator apart and did internal resistance measurements through each coil, and each contact. That is how I found that one wire had blown like a fuse. Replace that resistance measurements showed that one of the relay contacts had a high resistance. Burnished it with a dollar bill (which has always worked for me in the past) didn't work this time. Found some contact cleaning solvent, and used that and the dollar bill. That cleaned the contact. Soldered a new wire in place, and reinstalled the regulator.

Started tractor, and it worked. Shut off tractor and anchored all wires. Restarted it and it didn't work. More resistance checks, and found that contact had stopped making contact again. Finally found my burnishing tool (like a small really thin and fine toothed file) and cleaned the contact again.

Now it works the way it is supposed. :Tractor2: :fam32:

A job resists every effort to complete it!!

[Carl]

This is the old girl that has been causing me to scratch my head. Except that I don't have the eavetrough downspout on the exhaust now. It was suffering from the gas percolating in the gas line. I moved the gas line to the front of the engine.

[mbkerk]

This motor / generator talk reminds me of what a "friend" did to my old Cub Cadet 20 years ago...

I was greasing it up to help him mow his lawn, and he asked me if I wanted him to put some oil in the oil cups on the end of the m /g. I told him "sure" and went back to greasing.

Well, soon it seamed like he had been running that oil can a long time, and I asked him what the he!! he was doing!

He said "Seems like it is taking a lot to get it filled!" :00000060:

The generator did not make the day. The field windings were soaked with oil, and shorted out! At that time I could still get parts. Don't know if I could today or not!

I wonder whatever became of that guy... I never helped him with his yard work again!

[Carl]

I think that he went on to design a better generator/starter. The one on my tractor didn't have any provisions for lubrication at all. When I took it apart the bushings were still tight. The brush end has a bushing. The front uses a ball bearing.

I suppose that the only way that you could have saved the generator would have been to take it completely apart and use a solvent on it to wash the oil out. If mine went I don't know what I would do. Probably rewind it myself.

[mowdak1]

13.5 to 14 volts would be the normal alternator/generator output on any 12 volt system with fully charged battery Carl, even your car or pickup...