4x4tographer 2,443 Posted September 15, 2022 84,000 miles - performed a little preventative maintenance on the Onan 4,000 watt generator that is the beating heart of Gandalf's rear end. Our first oil change on the genny since we brought the rig home last year. We're sitting at about 730 hours of total use on the generator, the majority of which pre-dates our purchase. The rig is set up for more extended boon docking with a pretty robust battery and solar set up - so it makes sense to me the generator has some hours on it - however given the fact that Gandalf is 17 years old this year, that works out to about 42 hours of run time per year. I can't tell you if that is a lot or not. Regardless - we had to a little oil and air filter change. Especially the air filter - it was NASTY. Here's a close up of the carb for future reference. I did not perform any maintenance on the carb - I plan to work on cleaning it once it cools down here in Phoenix. Draining the oil is frankly easier than working on the Jeep, since I don't even need to crawl under the rig to access the drain plug. The oil weight recommended by Onan is an odd one that I was unable to source locally. Onan recommends an SAE30, or 15W-40 for our particular climate here in Arizona, due to the high ambient temperatures. I tried a few auto shops to no avail, which was disappointing - We had to turn to Amazon, which get it here within a few days. We landed on Onan's own brand of lube. Here's a shot of Gandalf, resting at Dogtown Lake after the long climb up the i17 from Phoenix. Had a great time at the 13th Annual Gala with the crew and saw our fair share of rain during the event. Despite the rain, no leaks - which is always a plus. We recently had all of our window seals replaced and the roof inspected by State Trailer in Peoria - looks like it all worked just fine. Contemplating swapping out the bathroom vent with a 2nd MaxxAir fan (we have one in the front of the coach) since our rear vent is acting up and won't open reliably. These fans are incredible, with a ton of air flow. 3 Share this post Link to post Share on other sites
Curly 695 Posted September 15, 2022 Just remember, Carburetor is French for " Don't mess with it!" 3 Share this post Link to post Share on other sites
4x4tographer 2,443 Posted September 15, 2022 Just now, Curly said: Just remember, Carburetor is French for " Don't mess with it!" No doubt - it's black magic to me for sure. The procedure I've seen popular with these generators is to run the generator for a good period of time (1 hour) on an alternative fuel source. Using a combination of high octane gas and Sea Foam. It's recommended to do this annually - so they say. I also need to get into the habit of going to the storage lot and "exercising" the generator under load once per month - which I've only done twice since we bought it a year ago. Share this post Link to post Share on other sites
Curly 695 Posted September 15, 2022 (edited) 2 hours ago, 4x4tographer said: No doubt - it's black magic to me for sure. The procedure I've seen popular with these generators is to run the generator for a good period of time (1 hour) on an alternative fuel source. Using a combination of high octane gas and Sea Foam. It's recommended to do this annually - so they say. I also need to get into the habit of going to the storage lot and "exercising" the generator under load once per month - which I've only done twice since we bought it a year ago. You didn't ask my advice, but here it is anyway.......... I'm going to disagree with your method. Nothing wrong with a little sea foam, but High Octane fuel does nothing for you. Hi Octane is for High compression engines that have a lot of combustion chamber heat. The high octane stops/reduces knock and ping, but has no other benefit. The gas companies would like you to believe different, but all you are doing is spending more money. I would also suggest you run the fuel in the generator tank so it doesn't sit there and get stale and turn to varnish. Put some Sta-bil or other brand fuel stabilizer in the tank. Thats what I use in my cars that don't see a lot of road time. Edited September 15, 2022 by Curly 2 1 Share this post Link to post Share on other sites
4x4tographer 2,443 Posted September 15, 2022 11 hours ago, Curly said: You didn't ask my advice, but here it is anyway.......... I'm going to disagree with your method. Nothing wrong with a little sea foam, but High Octane fuel does nothing for you. Hi Octane is for High compression engines that have a lot of combustion chamber heat. The high octane stops/reduces knock and ping, but has no other benefit. The gas companies would like you to believe different, but all you are doing is spending more money. I would also suggest you run the fuel in the generator tank so it doesn't sit there and get stale and turn to varnish. Put some Sta-bil or other brand fuel stabilizer in the tank. Thats what I use in my cars that don't see a lot of road time. Oh I totally agree with you. I'm just bumbling through and learning as I go - and I really appreciate your insight and the depth of knowledge out here in the group! I'd read somewhere else about installing a little shut-off valve on the fuel line feeding into the carb to allow it to totally burn up all of the fuel. The generator pulls directly from the main 75 gallon fuel tank, so there's a considerable reserve there . 1 Share this post Link to post Share on other sites
Curly 695 Posted September 15, 2022 Shut off valve is a good idea. I added one to my riding mower, I shut the fuel off and let it run dry. Its a good way to make sure the carb is empty. I've been doing it for about 5 years now, no problems. Are sure there isn't a shut off at the main fuel tank? I don't see one in your pic. I would think that if you take the line off the carb, the main tank will try and drain out through the fuel line. 1 Share this post Link to post Share on other sites
theksmith 3,588 Posted September 15, 2022 the photos in your last update aren't working Share this post Link to post Share on other sites
ob1jeeper 447 Posted September 23, 2022 (edited) On 9/14/2022 at 8:20 PM, Curly said: You didn't ask my advice, but here it is anyway.......... I'm going to disagree with your method. Nothing wrong with a little sea foam, but High Octane fuel does nothing for you. Hi Octane is for High compression engines that have a lot of combustion chamber heat. The high octane stops/reduces knock and ping, but has no other benefit. The gas companies would like you to believe different, but all you are doing is spending more money. I would also suggest you run the fuel in the generator tank so it doesn't sit there and get stale and turn to varnish. Put some Sta-bil or other brand fuel stabilizer in the tank. Thats what I use in my cars that don't see a lot of road time. I concur with this . High octane fuel has a slower burn rate, to keep the fuel from burning too quickly (pre-detonation) in high compression engines. As for the fuel shut off valve, it is un-necessary if you use a fuel stabilizer (which is good for BOTH of the carbs your main tank feeds), then simply start and run both the generator and main powerplant periodically, which is actually goof for more than just the carbs. as the electrical generating equipment can also use an occasional bit of run-time to both exercise it and confirm no issues are present that require rectification before heading out on a trip. JMHO and experience. YMMV... Edited September 23, 2022 by ob1jeeper 1 Share this post Link to post Share on other sites
