M1031 with Hobart G204 Welder Help

[gglithox]

Just picked up a M1031 Contact truck with a G204 Hobart Welder. Tried to start the Wisconsin engine of the welder and the starter just clicks. Thinking it has a bad starter. Dose anyone no how to get at the starter for removal? It is located on the back of the engine up against the front wall of the utility body. The body under the unit is open but it looks like you would have to remove the exhaust and rear drive shaft of the truck to get at the starter. Dose the entire unit have to be removed from the service body to service the starter? Dose anyone have a service manual for the G204? Any help would be appreciated.
Thanks Guy

 

[319]

If you have not already, download TM 9-4940-421-14 and TM 9-4940-421-14P from the resource section.

 

[ernieflash]

the whole welder is on rails , I am pretty sure you can slide it out sideways , but you still may have to disconnect the exhaust, make sure you can turn the motor by hand ( not seized) before you go crazy with the starter, good luck !!

 

[319]

the whole welder is on rails , I am pretty sure you can slide it out sideways , but you still may have to disconnect the exhaust, make sure you can turn the motor by hand ( not seized) before you go crazy with the starter, good luck !!

Can that be slid out enough to clear the door to get at the starter?

 

[citizensoldier]

Pull the spark plugs and look down the cylinders with a small flashlight. See if you have corrosion on the cylinder walls or valves.. If the unit has sat for a long time water will leak down the exhaust stack and sit in the cylinders.. Put some trans fluid down them or Marvels Mystery oil and let it sit for a couple weeks.. I would then try and turn it over with the plugs out.
I had one that did this and the piston was ceased and self destructed when I first turned it over.
It would be better to slide it out on the rails to work on the motor, starter.. ect..

 

[citizensoldier]

Oh and that is asbestos around that exhaust pipe! Wrap it in saran rap and soak that fitting like crazy..

 

[gglithox]

Thanks all for your input. Manuals will be very helpful. I see now how the unit pulls out on the rail system. I removed the spark plugs and every thing looks good inside the cylinders I then pulled the panel in the passenger side front compartment and removed the shroud around the flywheel and the motor turns freely. Now to find a new starter. Thanks for the heads up on the asbestos.
Guy

 

[Recovry4x4]

I have an extra one that I'd like to see go away if you need one for parts.

 

[citizensoldier]

Ok so if the motor turns free I would then check all your wires and connections on the control box for corrosion. It the funny shiny box with a tube thing plugged in the top.If I remember right the power goes through that and then to the starter. Also check the ground from the battery this could be bad. Or bypass the ignition switch and welder part and see if the starter turns it over. This might save you some work changing a good starter.

 

[markinnh]

i just jumped mine with cables and fixed the fuel pump and it took off...needed a new battery for a cool hundred (some huge type 31 commecial battery)...I assume you checked that.

 

[markinnh]

note before sliding out the unit, dont forget the air compreesor wiring and the switch wiring for the behind the panel light....
I seems funny that one would design this so it had to be romeved from the truck to fix

 

[gglithox]

I cleaned all conections, checked the ground, installed new deep cycle battery and still just clicks. It clicks at the starter and at that shiny thing with the tube on it. I did take power directly to the starter and it did engage and turn the engine over, so not the starter.(thanks for that tip) Any other ideas?

 

[citizensoldier]

It sounds like you might have a bad relay in the control box. Or maybe the start switch? Somewhere your loosing good power "bad connection"to the starter. Check the power output at the switch both in and out. If you have good power out of the switch trace it to the box and so on.. Starter wiring all clean and good connection? Did it turn the motor over good? No dragging sound? When I get a chance I will look at mine and get the wire numbers.. You can get the Hobart manual online or contact them and have one sent.
Oh... hehehe.. the shiny thing you mention should be the ciliniod. Check for good power to that and its connection/broken wire ect..

 

[markinnh]

I think the over speed relay is what your speaking of when you describe the silver thing with the tube on top, only cuts power to the coil when the engine is over tached. At least that is my understanding. The start circuit is like any other, the swith in on and start sends power to the coil and to the solenoid mounted on top of the starter. Bad connections are a nitemare on those connections, or the solenoid is faulty. The click you hear, is it coming from the area of the starter? Make sure to disconect the battery, and a youthful lanky person may be able to reach the starter bolts with the right combo of extensions...re installing it may be tough but possibly doable....to test the solenoid, apply 12v to the small terminals and see if continuity from the big connectors is there. to proberly test this, the solenoid should be disconnected from the starter windings and this may require opening the starter motor case. If you do not feel comfy doing this take it to someone who can test it.

 

[Crash_AF]

Do you have the TM for the SECM body? If not, drop me a PM or you can go to the LOGSA website and download it. The number is 9-4940-421-14

I extracted the Start circuit from the wiring diagram in the TM. There are very few components in the circuit that could fail and prevent the unit from cranking. Have you tried putting 12V to the solenoid crank terminal? Do you have 12V at the start switch? The only component outside the start circuit that would prevent it from starting is the Ammeter, but if it goes 'click' when you hit the switch, I would assume that your problem is the starter solenoid itself.

Later,
Joe

 

[gglithox]

I spent most of the week end working on the welder/generator. Turns out that the starter solenoid was bad. replaced the solenoid and engine cranks. Had no spark so replaced points, condenser, cap, rotor, coil, wires and plugs and the engine fired right up. Thanks to everyone who helped me through this. Now it seams that the generator is not putting out power. Any suggestions? Printing out TM to read up on the oporating procedures.

 

[Crash_AF]

Glad to hear that the engine runs now... halfway there now...

Is the engine revving up to 1800 RPM? It won't produce voltage unless it is near operating speed, which is 1800 RPM. If it is ramped up to 1800 and still not producing power, then the field might need to be flashed in order to produce electricity.

It is supposed to do this automatically when you start the engine but if it's been sitting a while, the short flash may not be enough. If you reference the schematic above, it runs from the starter to DS1, then to the Voltage Regulator. DS is usually a light, but it appears to be something else in this schematic. It also appears that there is a fuse in the circuit at DS1 and that might be blown. If you can trace the wire from the starter to the regulator, you should be able to find the fuse and check it.

The Voltage Regulator is mounted beside the battery and overspeed relay. It is under a long cover. If you apply 12V to terminal 5 on the terminal strip while the engine is running, that should flash the field.

***** OBLIGATORY ELECTRICAL SAFETY NOTE *****
Always ground your generator to a good ground while operating, even while testing. These units produce hazardous voltages capable of seriously injuring or killing you.

Later,
Joe

 

[markinnh]

just a note..."DS" in the schematic is "door switch" me thinks...it turns on and off the light behind the control panel...i am surpised this lights being tactical and all....

Mark

 

[Crash_AF]

No, on military genset diagrams DS typically means 'light bulb' while S means 'switch'. If you reference the above wiring diagram extract, you will see that it has DS2 as a light bulb (the circle with the loop inside) and S3 as the toggle switch on the panel, but Door Switch is written out as the NC button switch that turns the light off if you close the cabinet door with S3 left on. Since there's an S2 and S3, I'm assuming the door switch is S1... but it's not labeled as such on the diagram.

It is possible that DS1 is mislabled instead of being labeled F1 for fuse or something else since component DS1 includes a diode and a fuse, but then where is the other light since there's a DS2... frustratingly odd compared to the MEP wiring diagrams I worked with when I was in.

Anyway, long story short, the MEP troubleshooting section (since there is NO electrical troubleshooting in this manual) states that if the unit does not build voltage on startup, the field needs to be flashed. Either the fuse is blown, causing the automatic field flash circuit to not function, or the exciter field is too weak to flash with a short application of 12V because it's been idle so long and it needs a longer pulse to begin voltage generation.

In a MEP, you just hold the start switch in the START position until the voltage comes up since there is a starter cutout that prevents you from burning the starter up after the engine passes cranking speed but it doesn't look like this unit has that safety feature, so a manual field flash is in order by jumping 12V from the battery to terminal 5 of the voltage regulator terminal board, which is conveniently located beside the battery.

Later,
Joe

 

[Lyle J. Montgomery]

Ibought a hobart g 204 at an estate sale. The coarse and fine controul switch had been removed. The wires are unbolted , not cut and still have the numbers on them. I have a replacement controul switch and do not know the wiring diagram for the back of the coarse switch. I hace seen diagrams but can't read the print on the schematics. Can anyone help me with this