Big Blue 251d

[toolman]

Found one for sale with the deutz engine has 7100 hrs how long should they go before a rebuild. and thing to look for being a problem.

thanks
Tim

[A_DAB_will_do]

I have heard that 10K to 12K hours is typical for diesel engines; but I don't have any real facts to support this. If I were buying this, I'd want to see is start from stone cold condition; watch it warm up and look for black smoke. It should be clear immediately after starting if the rings and seals are good. Is it an air cooled or water cooled engine? Check for leaks, the usual stuff. Strike and arc and see how it welds with some 5/32 or 7/32 E7018 rods. Check for crap in the fuel tank and water. Both are potential problems down the road for the fuel system. Watch the ammeter and temp meters on the unit...

[toolman]

Went and checked it out today. The battery was dead tryed to jump it, it would only turn over slowly, also the owner said it needed a new switch. It is the one you hold in while starting until it has oil pressure my Big 40 has the same switch. No welding leads the seller said he had used it for a generator only.Overall apperance was ok, engine was clean the welder portion was also clean face plate was bad would have to be replaced. The owner is suppose to get a new switch and battery, I'm going to take some leads with me if he calls. Any ideas what it would be worth if it is working serial # indicates it was made in 1995. I beleive you may be able to jump around that switch does anyone know if you can.

Thanks
Tim

[TubularFab]

I just bought a 1994 Big Blue 251D this summer. The sheet metal needed some work, and it didn't run due to a bad shut down solenoid. But, it seemed to have good compression and looked good inside so I went for it - $400. I had it running within an hour - since there is an external shut down lever on the injection pump I simply disabled the solenoid and reinstalled it to cover the hole. It's too easy to shut off with the lever to justify the ~$150 for a new solenoid! Anyway, it too has 7200hours on it and runs great. This thing welds really nice - the smoothest stick welder I've used. (I honestly have not used many engine drives, though)

Mine does not have anything special to do when starting with the starter switch. There is a low oil pressure warning light, and I thought it had some kind of shut down, but you simply twist the switch to start it. Maybe it makes oil pressure really quickly? I still need to get a new battery for mine since the one that came in it won't charge up. It takes a group 51 battery, which is tall and skinny with typical round automotive posts. They seem quite pricey - $89 is the cheapest I've seen at walmart or parts stores. You could adapt a lawnmower battery I suppose.

Anyway, I really like the welder. The oil/air cooled engine is pretty simple, and with good oil care should go a long ways.

[toolman]

Tubular fab
I seen your pic's it looks better than the one you bought he is asking 900$. He said as I was leaving he would take 700$. So I'm on the fence.

[TubularFab]

Well, around here the best deal I came across on a bobcat or ranger gasser with around 4000hrs was in the $800 to $1000 range if it was working (usually smoking). So, as long as the deutz looks like it's had regular oil changes and filters and everything functions I'd think $700 would be a good deal. On mine just pulling the oil fill caps was all it took to be impressed at how clean the inside of the engine was.

[toolman]

Thanks for the information.
I went to pick it up today and the owner said he had been offered 800$ over the phone and the guy would be there Saturday to get it. So I told him if he could start it I would pay the same. He put different battery in it. It still turned over slowly he cleaned the cables it turn over real good but would not start he kept trying it finally started and ran for several minutes and stopped and would not restart. He tryed for about 30 minutes it never did restart. So i offered him 700$ that he said he would of taken last Sunday but he is going to wait until Saturday and see if the guy on the phone shows up and buys it as is.
So what do you guys think could be wrong with it.

thanks
Tim

[chrisr]

Could be a number of things bad fuel pump, trash in fuel system, air in fuel system from leaks, voltage regulator, low oil pressure. Seen all of these problems at one time or another with some of the deutz powered bobcats we have at work. Be aware parts for the deutz engines are expensive.

[toolman]

Come on I know some one has insight on this machine and engine lets hear your 2 cents.

Thanks in advance

[TubularFab]

Chrisr's info is dead on. Diesels hate air in the injection system. So, if it happened to have been run out of fuel it could still have air in the system even if he did put more fuel in it

[jsfab]

Come on I know some one has insight on this machine and engine lets hear your 2 cents.

Thanks in advance

You want an opinion???? Ok, 7000 hours is still 7000 hours. Everybody seems to get hung up on engine wear and tear, my experience, in all cases, the engines will far outlast the welder/generator side of the unit. Especially anything with electronics or PC boards in them, not so much with simple welder/generators. 7000 hours???? Ok, but just be sure you price it accordingly. Get the diesel fallacy out of your head, the engine might be fine, but if you gotta spend $$$$$ fixing pc boards, what's the point????

[TubularFab]

This machine has no pc boards in it... At least mine doesn't. It may have a simple one if it has the auto idle feature, though.

[toolman]

No PC boards . No auto idle just a basic machine. In good shape just a lot of hours and as stated above the engine usally out last the generator.

How did you disconnect the fuel cut off solenoid and make it manual.

[toolman]

Well I went ahead and bought it tonight 700$. Will get some pic's tomorrow. The refurb will start soon. Any one know the best place to get a new face plate.

Thanks

[smawgmaw]

Congrads toolman! Waiting to see the pics! You may check miller4less or with 7A749 for faceplates, they be able to help you or maybe even billswelderrepair. Goodluck!

[toolman]

A few pic's and what do you know about murphy switches.

[toolman]

Ok the fuel shut down solenoid was stuck. Disabled it by taking the arms off of it. Engine runs great now just have to shut it down manually.

Thanks
Tubular fab for the idea.

[duaneb55]

Looks good toolman. Nice base to start from for a refurb.

ALthough they don't show any on their website http://www.decalshoppe.com/miller_welder_products you could check with The Decal Shoppe on a replacement faceplate. If they haven't done one for the 251D yet it'll be pricey as the first one gets to pay for the artwork and set up.

[duaneb55]

Yeah Steve, I forgot you mentioned your past bad experience and would have to agree with your take as a result. The artwork and setup fees are why I didn't have them do one for my Roughneck 2E. Should have pointed that out to toolman.

So those Miller labels were done locally? They are super nice and thanks again! I've got a local gentleman that does great vinyl work make a new face and side decals for that Airco MIGet I have due to your suggestion regarding the topic.

[TubularFab]

Glad to hear you got it running! Sounds like you did exactly what I did - removed the lever on the inside of the solenoid so it couldn't function. I was ultra ghetto about it - I drilled a small hole through the end cover of the machine and ran a piece of .093 304ss tig rod from the manual shut off lever to a loop outside the machine. Just turn off the ign switch than oull the ring to shut it off... I'm ok with pulling on the wire instead of spending $150 or whatever they cost for a solenoid so the switch can turn it off.

We have run mine here at school for a total of about 6 hours now, and it welds much smoother than any of the Miller XMT's, Synchrowaves, or Lincoln Precision Tigs we have in the shop. It even seems to smooth out most of the students' 6010 work.

Now, I have found one odd thing about mine. I had to make new terminal posts and leads to go from the rectifier to the terminals since mine had been burned up and rigged. When I got done I put a voltmeter on the output to make sure I had the polarity right, and discovered I'm getting 136volts OC instead of only 80 - 85. So, Monday I put a tachometer on the engine and confirmed it was running dead on the 1850RPMS listed in the manual. I'm not sure why the OCV is so high - but it welds great...

I wish I could trade the sheetmetal top off mine for yours! I got it flattened out pretty well now, and got the doors correctly hung. It definitely could use some paint! Oh - and I simply took a label maker to the front panel so you could at least see what you were setting the machine up at. Why don't you go ahead and pay one of the sign shops to make a new panel so I can then buy the cheap copy off ebay?

[toolman]

Just so happens I know a guy that owns a local sign shop . I had know idea they could do such work but I will check it out.
I have also found 3 wires behind the face plate that are just hanging loose.
1 # 46 it has adiode attached to it
2 # 103 it is atached to the fine adjustment rehostat. Wire 103 is attached to the rehostat and the a short 103 is hanging there.
3 # 9 is the same as 103 but on the other terminal
I have looked a the diagram just can not figure it out. I think they may have been optional wires for the guages for voltage and amperage?

[duaneb55]

What SN?

[toolman]

Kf 84864

[duaneb55]

I have also found 3 wires behind the face plate that are just hanging loose.
1 # 46 it has adiode attached to it
2 # 103 it is atached to the fine adjustment rehostat. Wire 103 is attached to the rehostat and the a short 103 is hanging there.
3 # 9 is the same as 103 but on the other terminal
I have looked a the diagram just can not figure it out. I think they may have been optional wires for the guages for voltage and amperage?

toolman, I don't know if you've got this sorted out yet and I apologize for being so long in getting back to you.

It sounds like the unit is or was set up for the optional high oil temperature / low oil pressure shut-down and remote fine current control.

#46 w/ diode is part of the low oil pressure shut-down and would either be connected to the control panel indicator light or harness plug 5 cavity 2 and provides chassis ground (-) to the magnetic shut-down switch MS1 with no oil pressure present at oil pressure switch S7.

#103 is either connected to the fine current control wiper terminal (w/o optional remote fine current control) or to the NO (normally open) side of the STANDARD / REMOTE panel switch S9 (w/ optional remote fine current control).

#9 should be connected to the fine current control common terminal and the slider terminal of tapped resistor R2 regardless if equipped with remote fine current control or not.

It sounds as if someone attempted a modification or repair and may have gotten their 'wires crossed' along the way. Unfortunately, not being there, this is the best I can offer with the information available.

Keep us posted.
Duane

[toolman]

Duane first thanks for the information.
The 46 wire I understand and can see on the diagram now.
The other two still have me baffeled. There is no remote options on the welder. There is a control relay which these wires will reach. But I'm not sure if the go there?
And I understand it's hard to trouble shoot things you can not physically see or touch.
Thanks again any more input would be a big help.