Starting Problem

[MudtrekkerMD]

My tractor is not starting correctly. When I turn the key, nothing happens but the gauges start working. If I jiggle the PTO levers to engage the sometimes troublesome sensor switch, it still makes no difference.

If I keep trying to start it, it eventually will start up but it seems to be getting worse every time. Is this a symptom of the starter solenoid going bad?
Will replacing the starter solenoid solve this starting problem?

It's getting so bad that I'm afraid one day it won't start when I really need it.
The tractor is a Cub 7275 Hydrostatic.

Thanks for applying all the great wisdom of you forum members to this little problem of mine.

Mudtrekker

 

[oldmech]

Hi! My opinion . 1 Do you have a good battery. 2 Check For cables connections and a GOOD GROUND metal to metal at the body from cables and solenoid to ground. etc 3. Look all protection relays clutch, pto ,gear box etc Good luck Oldmech

 

[redlinefever]

Not to be offensive, but since I am not sure of your mechanical expertise, I will keep this as simple as possible.

Usually a solenoid is a "works or don't work" thing, as long as it has clean connections that fit properly and snug.

A starter can be
1 - misaligned with the flywheel teeth so it does not engage properly but instead may bind up, usually check for loose mounting bolts and make sure all the teeth are ok on the bendix gear and the flywheel - i.e. doesn't have any burrs, missing teeth or misaligned teeth (some use a thermoplastic bendix gear)

2 - if it drags or gets too hot, usually a sign the armature and/or brushes are worn Very easy to bench test with jumper cables, just touch the post on the starter with the cable, don't leave it attached or it may "weld itself"!

3 - clean cable ends, no breaks in cables or corroded wires inside jacketing

IT IS NOT always the starter. Check to make sure all wires at ignition switch are connected properly, not worn through or grounding out somewhere.

Best to check harness for good clean connections everywhere and no pinched or broken wiring!

If it uses relays on starting circuit, important to make sure if it is a "diode" type before checking it with an ohms & continuity multimeter. They have a "triangle" on the circuit diagram on the side of the relay. Use an analog multimeter to check these. Any surge from a digital meter can kill the diode, since most digital multimeters require a 9v battery and some diodes only use 3 volts. Always make note of the number and position of the terminals in order to get the correct relay and copy the diagram. Can become an expensive mistake or a "no run" situation by using the wrong one.

Make sure battery is fully charged. Weak battery will cause many issues. Gauges can work at 3 to 4 volts, so don't rely on them.

Hope it helps.

 

[Bob_Bainbridge]

Not to be offensive, but since I am not sure of your mechanical expertise, I will keep this as simple as possible.

Usually a solenoid is a "works or don't work" thing, as long as it has clean connections that fit properly and snug.

A starter can be
1 - misaligned with the flywheel teeth so it does not engage properly but instead may bind up, usually check for loose mounting bolts and make sure all the teeth are ok on the bendix gear and the flywheel - i.e. doesn't have any burrs, missing teeth or misaligned teeth (some use a thermoplastic bendix gear)

2 - if it drags or gets too hot, usually a sign the armature and/or brushes are worn Very easy to bench test with jumper cables, just touch the post on the starter with the cable, don't leave it attached or it may "weld itself"!

3 - clean cable ends, no breaks in cables or corroded wires inside jacketing

IT IS NOT always the starter. Check to make sure all wires at ignition switch are connected properly, not worn through or grounding out somewhere.

Best to check harness for good clean connections everywhere and no pinched or broken wiring!

If it uses relays on starting circuit, important to make sure if it is a "diode" type before checking it with an ohms & continuity multimeter. They have a "triangle" on the circuit diagram on the side of the relay. Use an analog multimeter to check these. Any surge from a digital meter can kill the diode, since most digital multimeters require a 9v battery and some diodes only use 3 volts. Always make note of the number and position of the terminals in order to get the correct relay and copy the diagram. Can become an expensive mistake or a "no run" situation by using the wrong one.

Make sure battery is fully charged. Weak battery will cause many issues. Gauges can work at 3 to 4 volts, so don't rely on them.

Hope it helps.

Sometimes the Bendix gear will stick on the shaft and cause intermittent starting. I've had success on applying a thin coat of grease to the shaft and gear. Also if the contacts get burned or worn it may work off and on.
I don't believe that most nultimeters apply the 9 volts to a diode being tested. In my 39 years that I worked for IBM as a computer technician, I've NEVER blown a diode or transistor with a multimeter. This might be more probable with an old analog type meter.

Bob B.

 

[Rhoderman]

First, I agree with Bob about the diode scale on a meter. It won't blow up a diode. It can't source enough current. Only 22 years electronics experience for me though...


Back to the starter problem. On my 2042, I was seeing some similar odd behavior earlier this summer. I would key it to "start", and sometimes I'd just hear a faint click and no starter roll. A couple tries and it would go, but it didn't sound quite right, like the battery was near dead. Finally, one time it wouldn't go at all, no matter how much I tried.
I put the charger on it overnight (low current charger) and when I went to start it the next day, it still didn't sound right. After mowing for the day, I parked it where I could reach the battery easily.
The next day, I measured the battery voltage with my multimeter. It was 12 volts. Then I flipped it to start but only for a second, then off. When I checked the battery voltage this time, it was down to 10V! Aha! Dead Cell!

Now that I have a new battery, I haven't been getting the weird occasional no-start condition any more. Maybe it was the solenoid wasn't happy with only 10 volts? Who knows for sure, but my problems have gone away. I still would like to know why a 2 year old battery bit the dust though. I'm sure Cub uses the highest quality batteries they can find, right? Ha! It said MTD right on the battery...

Hope this helps a little. Suspect the battery even if it's less than 5 years old. Oh, and post back what you eventually find. It might help someone else here some day later...

Jim

 

[PUMA454]

I also have a Cadet 7275. All of them have the same problem and it is easy to fix. Basically the problem is, 12V power from the keyswitch goes thru a whole bunch of safety switches and lots of cord before it gets to the starter. By then, a voltage drop ocurrs which isn't high enough to trip the starter. This was also a common problem on early self-propelled combines.

The fix is easy and adds another solenoid in the system. When adding this solenoid, now the voltage going from the keyswitch thru the interlocks can drop below 10 volts but still trip the solenoid. The lead from this solenoid to starter is short and has full voltage and current.

I got a wiring diagram from another site and used it on mine and has worked flawlessly for several years now. I've passed this on to a half dozen other guys and they have had the same results.

I'm not good electrically, so had my local Cub dealer do it. He then did a whole bunch of other cub tractors as well. The solenoid listed is a cub part number but can be crossed over to another less expensive item according to some of the guys that gave me feedback.

I'm new to this site, so don't know how to pass info on. Just e-mail me at my website email address "badriver@badriverinc.com" and I will email you a .jpg file of the fix. It is an awesome tractor, however, you may experience two problems. The fuel lines can rub against each other and rub through just below where the FEL mounts and the loader mounting bracket bolts on the side of the engine can vibrate loose. You should check these periodically and add loctite. Cub also sold a re-enforcement bracket for the FEL mounting bracket. I also have a mid mount mower and this bracket needed altering to fit. Woods made the loader and this part is cheaper through them than Cadet. I own a machine shop, so we chopped and welded as necessary.

 

[Gator6x4]

Purchase a five (5) spade terminal relay. I like the type with a tab. This allows the placement of the relay near the starter with a sheet metal screw. Some like the type that mounts through the use of a bracket. The relay needs to have the following terminals, 30-85-86-87-87a. A auto parts store can supply. Or, if you want to spend big bucks purchase one from MTD/Cub Cadet. The part # for the Cub Cadet relay is 925-1375.
Remove the wire from the key switch to the starter solenoid. (Remove the wire at the solenoid - pull from the spade terminal)If you are lucky, install this wire on terminal # 85 on the relay. If unlucky splice a wire onto the wire so it will reach where you have mounted the relay. Connect a wire to terminal # 86 and attach the other end of the wire to a good ground. Install a wire on the terminal on the starter where you previously removed the wire from the switch, attach the other end of the wire to terminal # 30 on the relay. Install a wire with a 20 amp inline fuse on the main battery wire at the starteer or another 12 volt source. Connect the other end of this new 12 volt source to terminal # 87 on the relay. No wires should be connected to terminal # 87a. Now when you turn the key to start, the voltage from the switch collapses the relay and the new 12 volt source engerizes the starter. This no start or clicking problem started when safety switches where added to the start system.

Good luck - Happy starting.

 

[MajMac392]

MudtrekkerMD, PUMA and Gator have given you some good advice. This was a problem with the older 72XX series Cubs and the relay that they are discussing should take care of it. If you read/search and look long enough back in old posts of this forum and other tractor sites you will see it has been an irritant for a lot of owners. It has been a problem with mine 7234 as well but I haven't got around to ripping my dash apart to fix it yet.

 

[redlinefever]

Hmmm, I guess my mistake. Thanks for the info, learn something new everyday - LOL! I was taught that when performing a circuit test on a particular wire to check for continuity, always be sure of the circuit load. Maybe it's because of the intense electronics used in the newer trucks & cars - LOL!
Can't use this or that anymore, so many "on board computers" in that massive spaghetti of harnesses - LOL! One wrong surge when powering a circuit while bypassing a few others and poof there goes another few hundred dollars! Most of it is built so you can't even "hot wire" to override the ignition system when troubleshooting, like the days of old ... have to either build a "hot box" or buy an expensive one made just for that type of circuit for that particular model of auto or truck.
I wonder how long before tractors become overwhelmed with electronics, so that most owners cannot do more than change the oil and have to pay the dealer for any repairs?

 

[JSharp]

The diode setting on modern meters is there to test diodes not damage them. That setting will provide enough voltage to turn on a diode junction but not nearly enough current to damage even the lowest wattage diode I've ever seen.

When not in the diode test mode, modern meters won't even provide enough voltage to turn on the diode...