Kubota B21 stuck on side of mountain - stop solenoid issue?

[VTsteader]

Here's what happened:

I was moving some 1 1/2" stone for a friend (who does live on the side of the mountain ) when some white smoke along with a burning rubber/electrical smell came from under the hood and then the engine just stopped, no chugging or anything but just as if I turned the key off.

I checked under the hood and noticed the alternator belt was cracked in several spots. I thought that maybe it was slipping and smoking. I replaced the belt, got back to work and the same thing happened again only now the tractor turns over but won't stay running. I tried to track down the smell and it seemed to be coming from the area of the stop solenoid which was very hot to the touch and the back plastic cover was peeled back. After doing some research it sounds like it could be the stop solenoid based on what's happening... If that's the case could there be something causing it to overheat, if it did at all? Or could the problem lie elsewhere?

 

[CalG]

Fuel shut off solenoids are "controlled". My bet is that the controller is screwed up.

Electro magic black box with a hefty $$ burden.

 

[goeduck]

How much of a slope are we talking about?

 

[Tractor Seabee]

I would check the solenoid coil first. Many things can cause their failure such as age or moisture deteriorating the coil insulation. Does not seem the controller would cause a short inside the coil. It may be standard solenoid that has a after market replacement versus the expensive OEM item. I always check that route out first.

Ron

 

[CalG]

Assuming a three wire solenoid.

One coil that operates for only a short time pulls the fuel tap open. This solenoid will overheat if energized continuously.

A second winding HOLDS the fuel tap plunger open during operation. That one can be energize constantly without over heating.

A compromised environmental seal could cause either coil to let out it's magic smoke!

The slope of the hill has NOTHING TO DO WITH the smoke and burning smell. ;-)

Eta


An aside, my Hurlimann tractor has a two wire fuel cut off solenoid. It is a Normally OPEN device that is energized to CUT (close) fuel flow for a short time, and then reopens when the electrical power is off. The "controller" handles the logic and the timing.

 

[Tractor Seabee]

You learn something everyday. My BX only has one solenoid coil circuit, hence my thought.

Ron

 

[sea2summit]

Fuel shut off solenoids are "controlled". My bet is that the controller is screwed up.

Electro magic black box with a hefty $$ burden.

I had a very similar issue with my MX, gave me a code in the console as well. Ended up being a dirty connection between the sensor and the brain, there's a quick disconnect that was hidden on the back side of the engine so cleaned that out, plugged it back together and haven't had that issue since.

 

[thepumpguysc]

If your stuck, stuck.. remove the solenoid from the engine.. see if it will start.. you'll prob. lose some oil running the machine but it will be "splash oil".. Get to where u can work on it.. even if that means plugging the hole w/ Tape???.. until the problem can be sorted out..

 

[LouNY]

There are two different styles and multi configurations of fuel solenoids, some require power to run and some power to stop.
The ones with power to stop, have a controller that applies power for a few seconds to stop the engine and they will then release.
Most of the ones that require power to run will have two circuits one to pull in and one to hold, hence two or three wires.
It seems that Kubuta is one that likes to energize to stop.
If you disconnect the wiring to the stop solenoid and physically make sure your stop linkage is in the run position, your tractor will start and run.
To stop you have to manipulate the stop linkage by hand.
Also if yours has a solenoid that is mounted right on the injector pump you can unbolt it as thepumpguysc says.

 

[Gordon Gould]

There are two different styles and multi configurations of fuel solenoids, some require power to run and some power to stop.
The ones with power to stop, have a controller that applies power for a few seconds to stop the engine and they will then release.
Most of the ones that require power to run will have two circuits one to pull in and one to hold, hence two or three wires.
It seems that Kubuta is one that likes to energize to stop.
If you disconnect the wiring to the stop solenoid and physically make sure your stop linkage is in the run position, your tractor will start and run.
To stop you have to manipulate the stop linkage by hand.
Also if yours has a solenoid that is mounted right on the injector pump you can unbolt it as thepumpguysc says.

I would go with this idea first then try the other ideas if necessary. Many Kubota selenoid fuel valves, if not most, are normally open w/o any electrical power as Lou says.

gg