Bobcat 225G becoming a Moneypit 225G

[Sammy67]

First off, Thanks for the add to the forum. I've learned over the years that the best part about hitting your head against the wall is it feels good when you stop. It's time I stopped and asked for some help. Last fall I found a 225G on Marketplace that ran but wasn't making power. I was told it had been in a tobacco barn for the past 20+ years. The guy had a meter on it (I don't remember where it was plugged in) and the voltage went up as he cleaned the slip rings. I bought it for $500 thinking I could put new brushes in it, clean the rings, and be a happy camper. Silly me. It's a late 1989 machine #JK733337 with 750 hrs. on the working hour meter. The following is a list of what I've done, checked and/or replaced in the hopes it would come back to life. New brushes, cleaned the slip rings. Meter shows 3.2 Ohms between rings, no continuity to shaft with brushes off. F1 fuse tests good in it's holder and out on the bench. This machine was built just prior to the F2 fuse being used. R1 rheostat was giving jumpy readings midway so it was replaced. Replaced D4 diode and SR2. New capacitor. New diode on SR1 since the old one was corroded from a mouse nest. Idle solenoid is new. It didn't work at first but seems to now after cleaning terminals on the start switch. I have had to jiggle the start switch between run and run/idle a few times if it didn't idle down. Cleaned the contacts on the range/polarity switches. The voltage regulator on the Onan is new and shows 13.5 volts at the battery when running. The idle/run RPM's were set at 2200/3700 using a digital tach (HF brand). Following Duane's tests I've gotten the following readings with wire off start switch, switch on, checking to ground: 11.5v at R2 #21. 12.3v on switch side of D4, 11.5v on F1 side. wire #24 at the positive brush has 12.17v with wire off terminal but only 8.3v when on terminal. I'm get a reading of 10v at the brushes when it's running. #23+#24 at rheostat show 9v. When running, the SR2 readings are 12.3v DC at + terminal, 0 at negative terminal. The AC terminals show 6.2v each. I've taken the wires off SR2 and it tests .750 + to - and .440 at the adjacent terminals with meter probes reversed (-on+, + on -). At 3700 rpm, the 120 outlets have 8-9v AC. The welding lead outlets have 20v with (-) probe on work and (+) probe on cc. I'm done throwing parts and $ at this thing and could use some guidance. Any help is greatly appreciated.

[Kpack]

We’ll for what it’s worth I would have bought it for 500 also.
I mess with old generators some and try to keep to the same kinds where I can swap out parts.
Hope you figure it out.

[smithdoor]

On older generations I clean the slip rings be fore even run the generator.

Dave

First off, Thanks for the add to the forum. I've learned over the years that the best part about hitting your head against the wall is it feels good when you stop. It's time I stopped and asked for some help. Last fall I found a 225G on Marketplace that ran but wasn't making power. I was told it had been in a tobacco barn for the past 20+ years. The guy had a meter on it (I don't remember where it was plugged in) and the voltage went up as he cleaned the slip rings. I bought it for $500 thinking I could put new brushes in it, clean the rings, and be a happy camper. Silly me. It's a late 1989 machine #JK733337 with 750 hrs. on the working hour meter. The following is a list of what I've done, checked and/or replaced in the hopes it would come back to life. New brushes, cleaned the slip rings. Meter shows 3.2 Ohms between rings, no continuity to shaft with brushes off. F1 fuse tests good in it's holder and out on the bench. This machine was built just prior to the F2 fuse being used. R1 rheostat was giving jumpy readings midway so it was replaced. Replaced D4 diode and SR2. New capacitor. New diode on SR1 since the old one was corroded from a mouse nest. Idle solenoid is new. It didn't work at first but seems to now after cleaning terminals on the start switch. I have had to jiggle the start switch between run and run/idle a few times if it didn't idle down. Cleaned the contacts on the range/polarity switches. The voltage regulator on the Onan is new and shows 13.5 volts at the battery when running. The idle/run RPM's were set at 2200/3700 using a digital tach (HF brand). Following Duane's tests I've gotten the following readings with wire off start switch, switch on, checking to ground: 11.5v at R2 #21. 12.3v on switch side of D4, 11.5v on F1 side. wire #24 at the positive brush has 12.17v with wire off terminal but only 8.3v when on terminal. I'm get a reading of 10v at the brushes when it's running. #23+#24 at rheostat show 9v. When running, the SR2 readings are 12.3v DC at + terminal, 0 at negative terminal. The AC terminals show 6.2v each. I've taken the wires off SR2 and it tests .750 + to - and .440 at the adjacent terminals with meter probes reversed (-on+, + on -). At 3700 rpm, the 120 outlets have 8-9v AC. The welding lead outlets have 20v with (-) probe on work and (+) probe on cc. I'm done throwing parts and $ at this thing and could use some guidance. Any help is greatly appreciated.

[ferrret3238]

I would have bought it for $500 also. I have 3 of them that i took apart to nothing and made 2 good running ones out of. One has a bad armature, another has a bad field, and the 3rd has a bad motor. I would check continuity on the field windings and make sure they're good too. One of mine had a dirty reactor, aka rust swelled, so i swapped it also. The high idle is set with a meter on HZ to get it at 60. But if you dont have 120 or 240 yet 3700rpm is close.

[Sammy67]

The field continuity checks good with a meter and I also tried Duane's light load test. The 100w bulb lit up the same connected to a 12v battery as it did thru the stator wiring so I think it's ok. One thing I did notice is the wire ties on the stator winding look like they got hot enough to bubble in a few spots. They are on the engine end of it. I don't know if that is a common thing from use and age or an indicator of something cooking elsewhere.

[Sammy67]

I think I found the problem. Bad spot in the stator winding. Attachment 1742523

[duaneb55]

Your photo attachment didn't work. Can you try again?

[Sammy67]