Kubota RW 25 Starter Solenoid Smoking

[bbaierl]

Hello all, Picked up a mid 80's Kubota RW-25 a few years ago and recently been giving it its first moderate workout in while. Seemed to overheat few nights ago. Cloud of white smoke appeared suddenly. Engine was running - even did its normal dieseling as I zeroed both throttles. Water temp gauge is unreliable but showed high range of normal. Smoke had acrid odor. Thought may have shorted something out. Was a cool night in high 40s so I let it cool off overnight. Next morning rad was about half full. Puddles below vent tube belied the overheat. Changed oil and topped off anitfreeze. Battery was dead. Jumped from Suburban. Wouldn't crank. Let charge 15 minutes and would crank. Motor turns fine but slow - white smoke from big wire connecting on starter solenoid appears as soon as I turned it over. Looks like it would burst into flames if I kept going. Going to spend Thanksgiving dawn taking apart and cleaning up connections. This is the second universal ignition switch I am going to be replacing so I'm guessing I have to find the right ignition switch for what I am told is a gray market Kubota. Saw a post about putting a JD relay to guarantee the solenoid 12Vs.
Any ideas? Thank you and Happy Thanksgiving...

 

[tthopskin@yahoo.ca]

well white smoke usually means antifreeze in the cylinder ..head gasket . if a motor heats up never shut down put it at a idle till it cools down ..shut them don hot and you will warp the head .. keep a eye on your oil if it goes milky or you see bubbles in your rad ..head gasket ..sound like your starter needs rebuilding too .good luck

 

[bbaierl]

Had some work related issues but got some stuff done yesterday that makes me feel better about the decison to shut her down. When this happened it was after sundown and it was tough to tell whether it was smoke or steam but it had that odor of burning. As I said gauges read normal though hotter than usual. I can get water to slosh out of overflow with enough joustling which was happening that night. Clincher is that the smoke ended when the key was removed from the ignition cylinder. The insulation is almost totally burned off the 4 gauge wire between the solenoid and the starter. Wondering if ignition cylinder was attempting to engage the starter while running.
Definitely need to get this starter solenoid checked out but it is going to be a challenge to get them out without the loader up. Should I just go ahead and R&R the starter/solenoid? This wire emerges from the solenoid case so is not replaceable but I could use cold-shrink wrap tape and get decent insulation. Thinking I may tru that and cleaning up connections before removing starter and solenoid.

 

[bbaierl]

And I need to find what ignition cylinder this should have. When I bought it it had a generic one and I have since replaced that twice. Going to do another because I can get one at Advanced and then maybe I can get the loader up. Thank you for any input available especially on where to ignition cylinder.

 

[lsmurphy]

All the soleniod is is a switch with a trigger, nothing more.

If you have a problem with the ignition switch you can always use a push button starter switch........common item at any parts store.......about $10.

Look into a Ford solenoid......something like a '78 F150.......$12-$15

New cables are a must at this point, solder your copper lugs. Check your grounds, move ground from battery to as close to the starter as you can.

 

[cycle_gator]

I suspect that if the coolant problem continues and it is the starter solenoid doing it's best to self-destruct that you have two different issues going on. If burning out ignition switches I would also give a hard look at how the starting circuit is wired. I suspect there is more current going through the switch than what it is rated to take. A 4 ga. wire to the solenoid is a dead giveaway. That is way more wire than what is needed for a trigger.

 

[bbaierl]

Thank you for all the advice. Ford solenoid is intriguing. Great to not feel like I am flying totally blind. Layout looks like the same on a BX-25 with the starter on the end of the engine towards the firewall. 4 Gauge wire is integral to the starter. Smoked real bad on the starter end. Starter cranks barely but draws down everything, incluyding my Suburban, so I am proceeding with getting the starter and solenoid off and to a rebuild shop. If I do the push button starter switch do I put the accessories on a toggle?
On a side note one mechanic that had looked at it years ago thought it might not have been originally 12 volt. Was originally sold in the 80s probably in Europe. Not sure about that...

 

[lsmurphy]

The Ford soleniod is sparate from the starter.

Starter switch is a momentary add-on switch. Ignition with acc. remains.

 

[bbaierl]

Well I humbly submit that in all likelihood the problem was a loose nut behind the wheel.
Ignition cylinder was faulty but the starter was toast and obviously had been engaged for some time while running that last session. The location of the key makes it likely that my knee hits it when jostling. I knew this but hitting it up should have moved the key to off position which I wouldn't notice because this does not shut down unless throttles are all the way off.
Took the starter to local shop. He said he could not rebuild it because armature was bad and he convinced me to get a new one. I told him I had heard that the new off-brand ones were problem ridden and he convinced me that he would stand behind it. New one is much more servicable (bolt up housing etc) and it sure cranks. Installed with starter switch and she starts better than ever (since 2007 for me).
Voltage is constantly right around 12 so no JD relay at this time. Old starter drew a lot more juice than this one. Found and replaced some mickey-mouse spliced wires that were probably shorting out while under the dash. Need to replace one to get the lights working.
Overall less than $300 in parts and she's running better than before. Thanks for all the feedback - good to not feel like I am flying blind. If there are any common concerns with Chinese starters please let me know so at least I am forewarned. Should I have gotten the old starter back?