Frustrating Kubota Starter Problems

[kebo]

Yep, it sure sounds like you have the same problem I had on my JD 750. A guy at a starter shop had seen it many times before and helped me fix the problem: When I turned the keyswitch, it would click, but not spin the motor over. Here's a clue to see if you have the same problem... turn the key switch over until you hear the solenoid click, then take a soft mallet hammer and hit the starter sharply with it a couple times (If that doesn't work get a regular hammer but don't break the casting!). If it magically engages and spins the motor over, then you will need to add the extra relay.

John Deere actually has a kit for this, don't know about Kubota. The relay basically jumpers over the heavy 12V starting current to the solenoid so it will "kick" a little harder when it engages. The voltage you measure on the starter and solenoid may be ok, but there is enough wiring/connection resistance throughout the entire circuit to limit the current getting to the solenoid. Even if the extra relay doesn't entirely solve the problem, it will help it work better especially on the cold mornings.

 

[wushaw]

Volt meter on battery, key in start position...what voltage are you reading?
Volt meter on starter (large) battery cable, key in start position...what voltage are you reading?

Also clean all your frame grounds & battery terminals, don't just look at em take a wire brush to em and make em shine.

 

[Treemonkey1000]

I am with JJ and his answers. If it is dropping to 7 volts with all of the current you are trying to pull it can be solenoid or connections. Relays get burned and pitted contacts will drop a lot of voltage with just a little pitting. Take off the battery terminals and cables. Look for oxidation. Brush up ground cables with a wire brush. Rusted ground bolts and also the positive terminals will mess you up. I have had starters and solenoids rebuilt and still fail. So it could still be bad. First thing to start with is take a look at the high current connections very closely....

 

[banjodunn]

G'day frustrating things these elec dramas :confused2: grab a set of booster cables and go from the neg side of the batt to the body of the starter that will isolate the ground circiut to the starter at least if you still have low voltage then try the same with the pos side , if this still does no good then jump from a good battery with the other vehicle running. One of these should give you 12 volts at the starter and should help you track down the prob


Jon

 

[J_J]

He has already proven that the starter works. The problem is the relay does not have enough voltage to pull in the relay, or the disc in the relay is severely corroded or pitted. If you ever take a bad one apart, you can see what could happen. Years ago, we would just clean the copper ring, turn it around, and re-install. I can almost bet that if he puts one of those thumb starter switches on the relay start terminal, it will start every time. He is doing the same thing with the screw driver.

 

[RickB]

I would introduce 12V to the start terminal on the solenoid (directly from the battery) and see if it closes and cranks the engine. I think that is the same thing J_J is suggesting. The solenoid coil will not close with 7v. Does the positive battery cable maintain battery voltage at the solenoid end while the control circuit drops to 7v?

 

[Gator6x4]

The man at the starter rebuild shop is probably correct, the starter and solenoid is good. The poster has already stated he can use a screwdriver and jump across the terminals and the tractor will start, so the starter and the solenoid is working. What is not being supplied is the 12volts to the solenoid. Remember where the poster said he was recording 7.2 volts at the solenoid when the switch was turned to the start position. To effect a fix, 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. If a fix is not desired we can continue the discussion.

 

[RickB]

The man at the starter rebuild shop is probably correct, the starter and solenoid is good. The poster has already stated he can use a screwdriver and jump across the terminals and the tractor will start, so the starter and the solenoid is working. What is not being supplied is the 12volts to the solenoid. Remember where the poster said he was recording 7.2 volts at the solenoid when the switch was turned to the start position. To effect a fix, 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. If a fix is not desired we can continue the discussion.

I'm not disagreeing with you. But that particular problem should and can be positively identified prior to purchasing & installing an additional relay. Reason being, there are other possible causes for the OP's symptoms, ie; a bad solenoid. .

 

[Chilly807]

When under load, as in cranking, the battery voltage will drop off to maybe 9-10 volts at worst in my experience.

If you're only getting 7 volts to the solenoid, it won't engage the main contacts and spin the starter. I'd say you need at least 8-9 volts for that.

If there is a relay in the circuit, which there usually is to save the key switch contacts, it's probably the culprit. If there isn't, the winding in the solenoid may be shorted, which will drag the voltage down. You can test that by checking continuity from the key switch lug to the starter case, it should be infinity.

Any continuity or resistance tests should really be done with the wiring disconnected. We already know there's a problem somewhere, so assuming a circuit is open can lead to false results.

If the starter works every time you jump the solenoid, and it started the tractor up to this point, I'd say you can rule it out. Also your main ground is fine, or else it wouldn't start, period.

You're going to have to remove the wiring from the starter and "start" (sorry about that, can't help myself) working your way back.

I think what's wrong is pretty simple, just a matter of isolating it.

Sean

 

[d1king]

Had similar problem with older b2400. Dealer wanted app $600 for wiring, switch, starter etc. several years ago. Turns out this is common concern, caused by cumulative voltage drop to solinoid as circuits age. Installed J.D. part no am107421, I, like several others, have had no further problems. Try a search for 'b2400 no crank', start with victor43 thread of 8/19/04 and follow thru. Has wiring tips, can also use low voltage automotive relay. I liked the J.D. relay because it went on so quick and neat. Good Luck