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Thread: Bobcat 225g Plus: arc quality, leads and onan questions

  1. #1
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    Bobcat 225g Plus: arc quality, leads and onan questions

    Well I picked up this good running/welding unit last week. No red flags. It idles down good and up just fine when striking an arc. Generator works fine too.

    I've already done some maintenance. I cleaned and greased the selector switches, cleaned the rheostat(still has some minimal pitting), resurfaced the slip rings and cleaned up the brushes. I also did plugs, air/oil filters, and fresh oil. Filled with fresh gas and some sea foam.

    On the engine:
    After removing the side covers I noticed oil residue around some of the head bolts on one side. They were loose so I retorqued them. I also did a dry compression check with the engine warm. The cylinder that had the loose head bolts came in at 60 at the lowest and just shy of 80 at the highest. The other cylinder was nearly 100. On the weaker cylinder I got some oil out of the decomp valve when I released the pressure on the tester. Could this be rings or maybe a head gasket letting oil into the cylinder through the bolt holes? Not an onan guy so I don't know. It does not smoke except for a puff of fuel vapor upon shut down. Starts fine too. There is a very slight puff puff every few minutes at idle and run rpms. I do know the valves need to be adjusted as the PO never had it done. Ideas?

    Arc quality:
    I have only ever used one other engine driven welder. It is a Miller bobcat 225 NT. The arc was smooth enough to have no complaints. On my unit it just seems to kind of spit a little bit. It sort of reminds me of my old Lincoln ac buzz box. It runs 6011 like anything. DC+/DC-/AC it is all as you would expect from a 1/8" 6011. 7018's are a little different. I'm getting a bit of harshness from the arc characteristics. Now the weld quality is just fine. I've run 1/8 Lincoln excalibur, 1/8 Esab atomic arc, and 5/32 Hobart. It's just the harsh dig type arc that I didn't experience from the 225NT. So do these just weld like that? I can live with it. I was wondering if it could be an indicator of a possible issue. It is nowhere near my Esab Rebel 235 or an Ideal Arc.

    Leads:
    Trying to decide what size and length of leads to get. This is of course to expand my small welding service to mobile capabilities. I want to stay with the Dinse 35-50 connectors the Rebel uses. I basically want to make extension lengths but have a separate set of whips for the miller. That way I can use them in the shop or on the truck. I think I already have about 50ft total with the bobcat and I believe it is 1/0 but I don't know for sure. The largest rod I run is 5/32 and I don't think I will be air arcing with this small of a machine. Is 75' for stinger and work leads a good start? What gauge should I go for considering I don't use more than 200 amps.

    Lastly, I have been told that this machine will not run a voltage sensing wire feeder. Even though it is CV and has the selection for it. Is it just for running a spool gun? Thanks

  2. #2
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    My attitude about these old engines (especially considering that parts cost a fortune)
    is that the oil WILL BE CHANGED EVERY 10 HOURS OF OPERATION.

    Compare the minimal cost of oil to one connecting rod,, and you will change oil,,,

    EVERY 10 HOURS!!
    JMHO

  3. #3
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    Yeah I found a rebuild kit for $1300. That's not happening. I would go through the heartache of a repower instead. 10 hours seems a little premature to me though. The oil hasn't even come close to breaking down. I don't see that preventing any sort of catastrophic failure. No amount of fresh oil will prevent the failure of a oil pump on deaths door.

  4. #4
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    It will run a VS feeder but you have to keep it on high idle. Just set the selector to mig and choose the appropriate range. I think the info you got was about a remote control feeder as it has no hookup for that.

  5. #5
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    The machine can be re-powered with a Honda when the Onan fails for less than 2500. I had a 95 model that I purchased new & just upgraded in 2018. Never had an issue with it except for voltage regulator. Was a good machine.

    Bought a 93 model at auction, went through it like you did, cranked it up & run it through paces. Seemed to run good/weld good. A couple of days later I was gonna crank it to see if the battery was still good (put a used one on it) & clank - dead stop. Tore it down & found a broken rod with old breaks. Must have been broke when I was testing it, but couldn't tell. Anyway it now has a Honda engine on it.

    Running 7018 try turning the course range up one notch & the voltage range (fine) down below 5 & see if it runs better. I used to run 6010 at about 6-7 (higher volts), 7018 about 4-5 (lower volts) on mine. Made a difference to me.

  6. #6
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    Quote Originally Posted by cwby View Post
    Running 7018 try turning the course range up one notch & the voltage range (fine) down below 5 & see if it runs better. I used to run 6010 at about 6-7 (higher volts), 7018 about 4-5 (lower volts) on mine. Made a difference to me.
    That's odd, I do the opposite.

    7018 likes voltage (in my opinion) so I run a range low enough that my volts are in 7-10 range.

    For 6010/11, use a range high enough to use lower volt setting.
    But truthfully I almost never do it - I just run them where I run the 7018's.
    Dave J.

    Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

    Syncro 350
    Invertec v250-s
    Thermal Arc 161 and 300
    MM210
    Dialarc
    Tried being normal once, didn't take....I think it was a Tuesday.

  7. #7
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    Quote Originally Posted by liberty_metal_worx View Post
    Lastly, I have been told that this machine will not run a voltage sensing wire feeder. Even though it is CV and has the selection for it. Is it just for running a spool gun? Thanks
    What MJD said.
    I've run a VS feeder off of my bobcat.

    Just note that the voltage you set is not what you'll actually get while welding - at least it isn't on mine.

    My feeder fortunately has a meter so I can see my welding voltage. Greatly speeds up getting the settings right.
    Dave J.

    Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

    Syncro 350
    Invertec v250-s
    Thermal Arc 161 and 300
    MM210
    Dialarc
    Tried being normal once, didn't take....I think it was a Tuesday.

  8. #8
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    Wow thanks everyone for the great information.

    A honda would be great. Any idea what series honda you have? I would like to know what the shaft specs are so I can plan for a swap if needed.

    I'm glad to know that machine will run a vs feeder. Does it have enough output to run dual shield and inner shield in .035?

    I used it on a job for the first time today. It is a real game changer for me. It beats dragging around that Rebel. I did notice the "digging" action with a 7018 was much less pronounced in the higher ranges at lower volts. Kinda neat to know that. I like to run 7018 as hot as possible but that digging action is annoying when I want it to behave. After I was done playing I got to work and kept the range selector in the middle and the fine knob at 5 and ran it for 6011 and 7018. It was fine. Nicer than the Rebel not having to switch to 60xx mode.

  9. #9
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    It will run .045 dual shield but not at it's maximum. On self shielded you can pretty much max out .045 wire.. You will need knurled drive rolls for your feeder and you also need electrode negative for self shielded wire.

  10. #10
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    "A honda would be great. Any idea what series honda you have? I would like to know what the shaft specs are so I can plan for a swap if needed."

    A company in Oregon specializes in re-powering equipment. Kit comes with everything you need, mounts, shaft transitions, wiring, solenoids, & instructions!. I only had to call once to get mine going.

    https://repowerspecialists.com/produ...=4367041265687

    May never be able to get the money back out of this one - I am right at $3300 on a 1993 model welder, but I wanted to see if it was as easy as they advertised to swap engines. It was & now I have the ONLY Bobcat I have ever seen with a Honda engine on it.

  11. #11
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    Re: Bobcat 225g Plus: arc quality, leads and onan questions

    I think I can get away with 2awg leads under 100'. According to all the charts. I will have two 25' lengths of 2/0. That will give me about 75' of reach to start with. I don't need to run 5/32" rods above 200 amps on this machine anyways. Nor do I have a wire feeder.......yet.

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