Question Onan Diesel Generator with Kubota 3 cylinder Diesel Engine

[rvkev]

I searched around here. Maybe the answer is under my nose, but I did not find an answer.

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I had trouble two years ago with the fuel cut off. It is actually called the "Fuel turn on solenoid" switch. I replaced it at Ocean Lakes a Campground. It was fine for two years. On the recent Independence Day trip the generator would not start again. I could see the fuel solenoid was not activating. Could this a "bad cheap piece of China junk"?

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I ordered another new one. When I replaced the fuel solenoid and the two relays that operate it, everything fired up and worked. About four minutes into the operation the solenoid was on fire bellowing out smoke like a freight train pulling a mile of cars up the mountainside. I shut the generator down, for fear of burning down the garage and BaRTH. It will not start or activate the fuel solenoid again.

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I removed the solenoid after it cooled and it does still react with a bench test. The auxiliary in still provides power on the start up switch. I put the burnt up solenoid back on and it does not operate. I am confused. The solenoid works on the bench though.

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Maybe the grounding is faulty. I installed a new ground to the frame. This was not the fix either.

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I searched several videos not coming up with any solutions. Being a sewer and drainage contractor, I am asking for solutions from this wonderful community. I found two service manuals on here, neither of which has led me to the fix. One of the manuals was a link back to Barthmobile's archives.

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I would like to solve this issue for all to see. If you want to private message me for a phone number so we can chat, that would also be great. I will still post the solution here, when we solve the mystery.

 

[Bigblockyeti]

Is the solenoid doing nothing while installed or does it just not have the power to physically pull in? I'm reasonably sure letting the smoke out, at least some of it, has decreased the force it could generate before the poof. It may be chinesium junk but in my experience at 2-30% the cost of OEM, it's often worth the gamble and if failure would prove to be particularly inconvenient, buy two and keep the spare handy.

 

[Joe Hogan]

IMO Chinesium is not worth the hassle. OEM is usually the most reliable, especially electronics. Plus you get access to Mfg Support if needed.

 

[Kevin D Pem]

IMO Chinesium is not worth the hassle. OEM is usually the most reliable, especially electronics. Plus you get access to Mfg Support if needed.

I gotta !!! So Taiwan is the greatest producer of chips in the world(China)! Kubota is a Japanese business!

I agree that OEM will increase quality, as that increases QC. but to be honest!!! OEM is most likely sourced from China!!!

Just because your solenoid failed means nothing about quality, only that you got one that failed.

 

[Joe Hogan]

Just a thought, have you verified voltage to solenoid? I've read that inconsistent/low voltage may cause issues.

 

[Wemustrv]

You had mentioned that they were also relays involved. They have to energize prior to the fuel valve. If you bench tested the shut off and it works I would be checking the relays. I would also make sure you have good ground.

 

[rvkev]

Simple electrical gremlins can cause hours of troubleshooting. I traded out relays. Tested relays for function and could not locate the issue. There are good ideas above in this topic, but none that solve the issue. The ground issue may be a contributing factor over the years.

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I did install a heavy ground because the unit is on rollers. The rusty rollers make for very poor grounding. A toad hitch cable with the plastic removed makes a perfect retractable ground cable. It retracts when the generator is rolled back in.

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The real problem is the little rocker switches on the electrical box mounted on the generator. I found this by accident. I was moving the switches and the fuel solenoid moved to activate the fuel arm on the injection pump. Then it did not activate the solenoid. I switched the rocker switches back and forth about 25 times. Then tried to start the old Kubota diesel. The fuel solenoid activated! I found the problem. It is close to 1 am. I am excited to post the SOLUTION. I will be spraying the old switches with JB 80, not WD 40. I think it will solve the poor contact issue in the switches. If the JB 80 does not keep the contacts clean I will order some new rocker switches.

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Now that is daytime I will add another contributing electrical gremlin to this post.

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The control box had vibrated loose from the vibration dampeners. Excessive vibration on the switches contributed to the switches jiggling around and making poor contact. It should be like new with new brackets and vibration dampeners. I will know the next time this BaRTH hits the highway on a hot afternoon that I want to run roof air conditioning.

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Below is a picture of the switches that are mounted on the side of the generator electrical box. If you have starting switch inside your coach, you would never know these are here.

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In conclusion the fuel shut off (actually the fuel turn ON solenoid) was never bad. The solenoid was getting low or no current thru the rocker switches.

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