Cub- 3 bad starters in a row?

[Cow]

I'm working on a Farmall Cub for a friend- she called me out a month or two ago and said her tractor wouldn't start. I figured out the starter was only working intermittently and would sometimes smoke- tapping on it with a hammer while cranking would get it to go but the thing was clearly dying. Oddly enough it didn't look that old.

She informed me that the guy she'd had working on it 6mo back put a "new" one in. Ok, weird. Found out they'd bought it from this website and we called in, got credit for the failed one and they sent another. This one did the same thing out of the box. I took off the brush cover and found the brushes were not being held tight against the commutator by the springs. I know they can be adjusted but it seemed to me more like the springs weren't doing their job. Either way this was a reman starter fresh out of the box, I shouldn't need to adjust brushes so we sent it back.

Starter #3 worked. Yay, problem solved..... except not. A little over a month later and we have the same issue of an intermittent smoking starter.

This is a 6v starter in a 12v converted tractor- I've always been told that's fine but I'm starting to wonder here. Battery cables are in good shape, battery has a good charge, we've tried replacing the switch(it's the manual type that sits on top of the starter).

I can only think of 2 reasons for this- either we're toasting these 6v starters by feeding them 12V which I always thought was fine..... or we've gotten 3 defective starters in a row which seems ridiculous but I did see that issue with the brushes on the second one so maybe that's the case?

Anyone been having the same problem or have any insight? If I send this back in we'll be on starter #4 and I really want to make sure this isn't my fault somehow although I can't fathom how.

 

[Janicholson]

It can be wise to desize the battery cables from original 0gauge to 4 gauge (found in cars) this reduces amp flow and slamming the drive into the ring gear. ask them to ship the new one from a different colored box! Jim

 

[paulsamwel]

I would get a twelve volt starter.As for
new/rebuilt defective parts,as a fleet
mechanic seen it many times.
Paul

 

[Fritz Maurer]

This is why shops often have a sign that reads, no return on electrical parts... just for instances such as this. Yesterdays Tractors did not have to honor any sort of warranty on this misused part. You have no complaint with them.

 

[kshansen]

(quoted from post at 19:27:53 10/20/22) It can be wise to desize the battery cables from original 0gauge to 4 gauge (found in cars) this reduces amp flow and slamming the drive into the ring gear. ask them to ship the new one from a different colored box! Jim

Not sure of difference between a Cub and my BN but I have been running it on 12 volts for well over 20 years with no problems.

I take that back many years ago I did replace the Bendix, but being this tractor was something like 60 years old at that time I can excuse that failure!

I'm not seeing how dropping the size of the cables will have any real effect as the amp draw will not be that high until the engine starts cranking.

If tapping the starter "fixed it" even temporarily I would suspect there was a problem in the starter, like brushes binding in their carriers or weak springs. Smoke tells me there is a poor connection someplace in the starter. Be it sticking brushes or wireing to the brushes of the fields.

 

[grandpa Love]

Battery cables may look good, but I
would replace them. Also check
connections. We have bought (dead) 45
cubs,fixed them and sold most to folks
who put them back to work. Most have 12
volt batteries and 6 volt starters.
Never an issue. A slow, dragging or
smoking starter is usually cable
issues. Also a cub should start in
about 2-3 seconds of cranking...... How
long is the starter staying engaged?
Maybe other issues.....

 

[riverbend]

It does not seem like you are getting anywhere swapping out the remanufactured starters. How about taking this one to a local rebuilder and asking them to look at it ?

Or if you are up for a little research, check the tension of the brush springs. If they are uneven or weak you will have found your problem. I haven't looked but would guess that Delco had a spec for the spring rate for the Cub starter. For the H the tension is listed as 24 to 28 ounces.

My 350 was converted to 12V before I got it and the original battery cables have not been a problem.

 

[SinkholeRoad]

(quoted from post at 05:59:34 10/21/22) It does not seem like you are getting anywhere swapping out the remanufactured starters. How about taking this one to a local rebuilder and asking them to look at it ?

Or if you are up for a little research, check the tension of the brush springs. If they are uneven or weak you will have found your problem. I haven't looked but would guess that Delco had a spec for the spring rate for the Cub starter. For the H the tension is listed as 24 to 28 ounces.

My 350 was converted to 12V before I got it and the original battery cables have not been a problem.

I agree with Riverbend. Go to a local rebuild shop. The guys at my local auto electric rebuild shop have always fixed my problems. They also have some great advice when dealing with a mystery like yours.
Good luck
Sinkhole Road

 

[jimtrs]

Just for reference, for those that may not realize, a cub battery cable is 7 feet (84") long. It needs to be in good working order.
The ground cable is notorious for problems. They are often still mounted as original - to the side of a rusty old battery box that's usually rusted and rotted where it bolts to the torque tube. I have always put in a longer strap going down around the battery to one of the battery box mounting bolts, bypassing the sheetmetal box. Obviously after some serious cleaning.

 

[kshansen]

(quoted from post at 20:19:00 10/21/22) Just for reference, for those that may not realize, a cub battery cable is 7 feet (84") long. It needs to be in good working order.

Guess I need to get out more, only really been near one Cub and that was many years ago. Kind of hard to imagine that on a little tractor like that it could take 7 feet of cable to go from battery to starter! And yes good tight and clean connections are the key to any electrical system.

And some people forget this is true for both the ground as well and the hot cable. What goes out has to have a way to get back into the battery! An electrical system is like a chain, only as good as it's weakest link!


This post was edited by kshansen on 10/22/2022 at 04:42 am.

 

[Janicholson]

As long as the cables are, smaller can drop the voltage during initial spinup and as well through cranking. It just make the voltage and amps closer the the original. the starter will still crank like the dickens. Jim

 

[DR. EVIL]

A company called FONDY AUTO ELECTRIC advertises in RED POWER Magazine, they used to have a satellite shop here
in Madison, Wis, I bought a couple rebuilt alternators from them and had them rebuild the starter on the Super
H. They run a route truck to pickup points once a week and inspect the part or parts you sent them, they call
you with a quote, and if you agree they do the work and you get your starter or generator back the following
week. And in my experience it will be better than new.
I suppose if you called them they would let you UPS a starter or generator to them for rebuild.
The starter I had them rebuild I had bought in about 1990 from a tractor salvage yard in Western Iowa,
supposedly they rebuilt it before shipping, but according to Fondy it was poorly slapped together, surprising
it lasted as long as it did. With my BIG new 12V battery the first time I started the SH, it spun over so fast
it scared me!

 

[BarnyardEngineering]

Are these "rebuilt" starters or aftermarket starters?

I'm pretty sure this site sells only NEW starters. They have an overseas aftermarket and a new Delco. Prices are VERY different.

12V starters for Cubs are hard to come by, and they don't have saddle switches, as they were activated by a solenoid. It is also completely unnecessary in this application.

12V to a 6V starter is only a problem if you crank and crank and crank and crank and crank and crank, or if the starter was bad in the first place. When the tractor doesn't start up with 5 seconds of cranking, fix it.

 

[kshansen]

12V to a 6V starter is only a problem if you crank and crank and crank and crank and crank and crank, or if the starter was bad in the first place. When the tractor doesn't start up with 5 seconds of cranking, fix it.

Agree, actually running the starter at 12 volts is easier on them. Lower volts means more amps and more heat.

I know this thread is about a Cub but my BN with a magneto seldom takes 2 seconds. Most of the time probably less than 1 second unless I forget to give it some choke when it's below 50F!

This post was edited by kshansen on 10/24/2022 at 05:47 am.

 

[Cow]

Finally got back to this again, she wanted me to try rebuilding it. I pulled it apart and this is what I m seeing. Commutator looks pretty beat up, brushes seem beat up. Brushes are mostly still there but a couple were rough looking. I cleaned it really good with some scotch-brite and reassembled. Bench tests great. Don t have a lot of confidence in it though and I m at a loss as to why this is happening unless it really is 12v being too much for it but that goes against everything I ve been told about these 12v conversions.

 

[kshansen]

Do all the brushes look like the one in the second picture or only that one?

I know in the original post you mentioned something about brushes not being tight on the commutator, was it the same for this one?

Also is the commutator burned like that all around or just in that one place.

Not being there makes it hard to say what the problem is but it looks from here like one or more brushes are not making good contact with the commutator.

I'm sure there is a spec somewhere as to how tight the brushes are held to the commutator but not sure where you would find that to measure.

 

[kshansen]

deleted duplicate post.

This post was edited by kshansen on 11/15/2022 at 03:25 pm.

 

[Cow]

As far as I could tell, this one was holding good brush tension but that one was a little dirtier than the others. I did notice with the cap off the brushes seemed to be able to catch on the housing occasionally but I don't think that's an issue when the armature is actually installed.

I guess we'll run this and see what happens. I am not used to pulling starters apart and only know enough to be dangerous so maybe I'm missing something but IDK what.

 

[tn terry t]

(quoted from post at 18:29:57 10/20/22) I would get a twelve volt starter.As for
new/rebuilt defective parts,as a fleet
mechanic seen it many times.
Paul

theres a diameter difference between the 6 and 12 volt starters and because of this you may need to change the water inlet because it has a indention for the larger 12volt starter motor

 

[BarnyardEngineering]

That does not look like a recently rebuilt starter at all.

 

[BarnyardEngineering]

(quoted from post at 18:33:16 11/17/22)

(quoted from post at 18:29:57 10/20/22) I would get a twelve volt starter.As for
new/rebuilt defective parts,as a fleet
mechanic seen it many times.
Paul

theres a diameter difference between the 6 and 12 volt starters and because of this you may need to change the water inlet because it has a indention for the larger 12volt starter motor

Hmm, I put a 12V starter on a 1951 Cub and I don't recall any problems with clearance on the water elbow. They're bigger around but they're also shorter.

Only reason I did that was because I blindly bought the starter used because it was the least expensive one I could find. Forgot that the 12V starter does not have provision for the saddle switch, so I had to rig up a starter button off a Farmall H.

 

[Jim Becker]

(quoted from post at 08:15:56 11/18/22)

(quoted from post at 18:33:16 11/17/22)

(quoted from post at 18:29:57 10/20/22) I would get a twelve volt starter.As for
new/rebuilt defective parts,as a fleet
mechanic seen it many times.
Paul

theres a diameter difference between the 6 and 12 volt starters and because of this you may need to change the water inlet because it has a indention for the larger 12volt starter motor

Hmm, I put a 12V starter on a 1951 Cub and I don't recall any problems with clearance on the water elbow. They're bigger around but they're also shorter.

Only reason I did that was because I blindly bought the starter used because it was the least expensive one I could find. Forgot that the 12V starter does not have provision for the saddle switch, so I had to rig up a starter button off a Farmall H.

oth the water elbow and the engine block were changed to provide proper clearance for the 12-volt starter. IN PRACTICE, people have found that a lot of the time an earlier engine has enough clearance for a 12-volt starter. It seems to depend on individual variations of the two castings.

 

[tn terry t]

i did said you MAY need to change