Engine Driven Welder Electrical Issue

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Hey all. I have a Hobart Champion 10000, pretty much a bare bones Bobcat 225. 20 horse Kohler engine. A couple months ago I mistakenly left the ignition switch in the "run" position for a couple weeks. The welder had an electric fuel pump on it, and one day while I was working in my garage, I heard the pump make the noise it makes when it's typically turned on. This is when I discovered I left the ignition on.I assumed I burned the pump out so I installed a mechanical one I had laying around. No luck. So after a lot of investigating, I discovered the fuel shutoff solenoid is not getting power in the "run" position. It does get power in the "start" position while cranking, so the welder will fire up for about 1 sec and then die.I have checked the wires for shorts or breaks, the low oil pressure switch is working correctly, the PC board doesn't have any crap stains on it and the "run" wire doesn't pass through the board anyway, the ignition switch is testing fine, the fuse coming from the starter isn't blown. Really not sure what else to check. Does anyone have a suggestion?The serial number is LC471626. I believe it's an 04 model.
Reply:I'd double check the OP switch.  It has to close to feed 12V+ from RUN to the fuel shut-off solenoid, the ignition relay CR1 and to wire #20 of PC1 PLG5 pin 5.  START does the same thing thru diode D8 which is why it'll run in START.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:You can bypass the OP switch with a jumper and see  if it runs in RUN.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Interesting development:Last night I made a little bypass jumper which did not solve the problem, and bench tested the oil pressure sensor, which tested fine. Figured I'd go try the jumper one last time before responding though. The welder fired right up. Then I tried it without bypassing the oil pressure sensor and it also started fine.The battery was reading 12.5v yesterday and it was cranking strong but I hooked up the trickle charger overnight anyway. Before charging, the fuel solenoid was seeing 10.5v (an online article said that was within acceptable range) in the start position and nothing in the run position. Now it's reading over 12v in the run position.Maybe I win the dingus award of the day but wouldn't I have been getting SOME voltage at the fuel solenoid, even if the battery was slightly low?
Reply:I just replaced the ignition switch wire terminals on mine for a similar issue. They just weren’t making good contact. With the new terminals on there is a lot more tension in the plug when installing it.
Reply:Originally Posted by ShwoodyInteresting development:Last night I made a little bypass jumper which did not solve the problem, and bench tested the oil pressure sensor, which tested fine. Figured I'd go try the jumper one last time before responding though. The welder fired right up. Then I tried it without bypassing the oil pressure sensor and it also started fine.The battery was reading 12.5v yesterday and it was cranking strong but I hooked up the trickle charger overnight anyway. Before charging, the fuel solenoid was seeing 10.5v (an online article said that was within acceptable range) in the start position and nothing in the run position. Now it's reading over 12v in the run position.Maybe I win the dingus award of the day but wouldn't I have been getting SOME voltage at the fuel solenoid, even if the battery was slightly low?
Reply:I didn't see any sort of relay. All the terminals felt secure but maybe it was just a poor connection somewhere that is now making contact after being messed with. Hopefully the problem doesn't come back but if it does, I'll cross that bridge when I come to it ha.Thank you everyone for the advice.