Miller bobcat 225ntblows fuse when you put fuse in

google miller bobcat 250 welder generator manual

copy and paste

https://www.manualslib.com/manual/1675586/Miller-Bobcat-250.html

Double check that you have 12VDC+ constant voltage at Red/black wire, as well as 12VDC+ when key on at Red/white wire .

millerwelds.com will let you down load a manual for this unit, it can help you with this problem, also you can call miller and tech support should help

check all your wireing

I had a problem like this a few days ago try taken of the air filter to were u can see the choke it may not be opening rite just cause it opens don't mean itsnot opening rite get a small spray bottle put gas in it and as u start ur welder spray the choke with with the gas a lil if it starts turn ur switch to run for while it workd for me if that don't maybe change the spark plugs

What model of suitcase? Could be the contactor in the suitcase, could be the mig gun. Are you using the CV setting on the Bobcat, instead of CC? Is the Bobcat on the high CV setting and the dial most of the way?

Have you checked the A/C relay? Usually located in the fuse box under the hood, you can check for power to the relay with the A/C switched on, or just swap it with another of the relays in that box with the same part number. If that doesnt work, check the wiring coming from the wiring harness that plugs into the A/C compressor. First check the plug for corrosion, clean it, then begin to trace wiring backwards a ways to see if there is a bare spot causing it to ground out.

See if that helps.
Mike

Look under the coach near the slide and look for a pinched or bare wire. Sounds like you have a dead short to ground and could be difficult to find. Check the wiring to the slide motor, could be between the slide switch and the motor. Take a Volt meter and set it to Ohms. With the fuse out check to see if you get an Ohms reading between fuse wire and frame of coach. If you get a reading you have a short. Also check the power wire on the slide motor to motor case. If you get a reading the motor is shoted and needs to be replaced.
Thanks for using Fixya
Jerry

have the power supply checked it may have gone bad.