Damaged Miller Bobcat 250 propane powered welder

At an auction, I bought this damaged Miller Bobcat 250 welder that had
a mounting provision for a propane tank on the rear.
As you can see, the welder was clearly dropped and looks bad.
However, even though it looks ugly, like a man after a barroom brawl,
with a black eye and a split lip, it does not seem to be internally
damaged. The engine, specifically, looks fine, as does the electronics
in front. The front is chewed up somewhat, but all the switches and
relays seem to be OK, miraculously.
I paid $100 for it and I want to fix it. I hope that it will be easy,
though I may get surprises.
I wanted to ask if anyone had similar projects and, if so, what
caveats and hidden problems did you discover? How to double check
engine prior to trying to start? Is jumping a battery OK or I should
rather just swap in a known charged battery?
Reply to
Ignoramus20081
Loading thread data ...
do you have picture link?
I normally use known good components where i can, reduces variables when there is a problem.
Or test the battery in another machine after charging and letting it sit. In my case, I have a battery load testor, tells me not just good or bad, but how good is it.
Karl
Reply to
Karl Townsend
Gee, my X-Ray Vision must be busted again...
Cosmetics don't perform useful work. They only count when you're trying to sell it for top dollar - and if it looks *too* good it actually works against you.
Running first, cosmetics second. Or it might be a waste of effort.
The only way to "double-check" the engine is to get a wrench and walk it around a few turns. Pull the sparkplug and squirt in a little oil first, just to protect the bore, then walk it around and make sure it spins.
If you want, leave the fuel off and check the compression with the starter motor first, or get a Cylinder Leakdown tester and park it at TDC. That will tell you if you have a burnt valve or other internal problems.
And if it uses Exciter Cranking rather than a Bendix-style 12V starter motor (essentially Gear Reduction through the bendix and ring gear) use the Welder maker's specs for compression - it will be spinning the engine at a different speed and torque with the direct-drive exciter.
You don't want to leave a totally dead and internally open or shorted battery in the electrical system - If it won't come up at least part-way with a Distilled Water top-off and a trickle charge, get it out of the circuit and use a known good battery. If it's good but too weak for extended cranking, it can stay inside and hook up a jump pack to test the unit.
BUT don't spend money on a special battery (a U-1 Garden Tractor or a Motorcycle sized battery) that fits the cavity till you have a runner - unless you have other uses for it. Use jumper cables and let the external battery sit on the ground next to it while testing.
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Reply to
Bruce L. Bergman (munged human readable)
I am so sorry. Here it is
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Great idea
Yep. I will follow up on this. Thanks
Reply to
Ignoramus4028
sorry
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I will just swap the battery. I recently bought a welder with a bad board, it happened because the board was unprotected from damage due to jumping of a dead battery.
i
Reply to
Ignoramus4028
After that hard of a hit I would suspect the battery just on general principles - very likely some internal breakage and maybe shorting. Rolling the motor over by hand first is a good idea, just to make sure the crankshaft or generator shaft didn't get bent since they have things cantilevered off of them (each other, plus a flywheel). Starting it is probably the only way to tell about the bearings but my guess is that the internals were well supported and fine. So, pull the old battery, roll it over and if it looks good, jumper cable in a good battery like Bruce suggested and fire it up :-).
----- Regards, Carl Ijames
I am so sorry. Here it is
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Great idea
Yep. I will follow up on this. Thanks
Reply to
Carl Ijames
Jumping should be fine. If it is only sheet metal damage you got yourself a real deal. That's an EFI equipped engine IIRC - so dual fuel (propane or gasoline) is pretty simple. Check whichever fuel system you intend to use for leaks/damage before attempting to run.
Reply to
clare
Looks more like someone backed ito it with something.
Reply to
clare
Maybe so. It is hard to tell by now.
i
Reply to
Ignoramus4028
I reviewed the pictures again. I now believe that something was dropped on this welder. Look at how the left (from face) sheet metal panel is bent.,
i
Reply to
Ignoramus4028
Certainly possible, a gas/lp welder on any sort of metal building erection project is certainly in the drop zone if a sling slipped, the telehandler hit a bump, etc.
Reply to
Pete C.
Looks like the sheet metal saved the contents. Not as bad as I had thought. I blew up the photo 400% and scanned everything I could see...nothing appears busted or even damaged. One can probably save the front control panel and simply order new sheet metal from Miller and have a very nice welder.
You may indeed. Shrug.
Remove ALL of the sheet metal before proceeding. Do NOT toss the sheet metal..it may well be straightenable with a dead blow hammer. Wont look pretty..but it will likely be usable.
Just check wiring on the back of the front control panel for any leads that were pulled free, spin the engine by hand..then try the starter..then add propane and see if it will start. Its not as bad as you think.
Gunner
Reply to
Gunner Asch
Or they dropped it and it turned over on its way down and landed upside down.
Reply to
Gunner Asch
Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:
Not necessarily, but it's also not necessarily true that "something was dropped on it."
It's equally possible that it fell off the sling they hoist these things into the air with on cranes, when knocking off work on-site.
In that case, it may have fallen a substantial distance onto its head.
URK!
Lloyd
Reply to
Lloyd E. Sponenburgh
Yes, indeed, I already brought it to my warehouse, and could not find anything damaged, other than sheetmetal.
Yep, I am kind of psyched up.
i
Reply to
Ignoramus4028
Then the front handle bars would be bent also.
Reply to
Ignoramus4028
Then the handlebars wuld be bent also, which they are not
Reply to
Ignoramus4028
I'm still voting for something ran into it.
Reply to
clare
I will try hard to arrive to my own "best forensic guess" when I look at it closely and I will follow up on this.
i
Reply to
Ignoramus4028
OK, an update.
1. I did a thorough visual inspection. I concluded that the face of this welder is badly damaged cosmetically, but no front controls were actually damaged.
2. I found that no electrical terminals on the rear of the front panel, touch each other where they should not.
3. I found that the motor was not damaged in any way.
4. I hooked up a 12V power supply to the battery, setting voltage carefully so as not to damage any circuit boards.
5. Upon hooking up propane, the welder started and ran fine. I ran it twice and in both cases shut it down within seconds of startup, so as not to damage anything.
This is it for now. I want my guy to power wash this welder and check out the motor more thoroughly before proceeding further. I think that it will be found to be fully functional, but I want to stay on the safe side.
I have a question, can one buy a replacement panel?
i
Reply to
Ignoramus13376

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