Generator use

I have run over 10 Onan 4000 KY over 2500 each with no problem. Check the oil every 8-10 hours. To check the oil, turn off the AC, let the Generator run for 4-5 minutes to cool down, turn it off, check the oil, add if needed, start it up and continue to run. I have run them for up to 110 hours straight this way several times, no problem.
I do use synthetic oil, no regular dyno. Temperatures are too high so you can really use synthetic oil for this application.

Ah, which is why I asked. The manual I have shows straight 30 for hot weather, or 10W-40. Looked at the link, and it seems the stiffest offered in Annual Protection is 5W-30, which incidentally is the grade I'm using in our four vehicle engines. Toyota and Nissan calling for 5W-30, and one Ford that was 10W-30 and another 5W-20. Looking at 15W-50 for the boat once the MerCruiser warranty's out. Using that for the ONAN would leave me with only two oils to stock. MerC's oil is a 25W-40 Syn/Dino Blend. Go figure.
The guys on the boat forum often include this question about oil selection: How many cases of engine failure from oil breakdown have you heard of? Consistent answer is NONE. Only case I remember in automotive was the early versions of 10W-40 did in fact break down and trash a bunch of car engines. Warranties were voided if it was used.

j-d wrote:
Which weight? I ask because your rig is newer than ours. Manufacturers change their specs based on old experience and new developments such as better oils. But the print in the Manuals doesn't morph into the latest recommendations. I've seen that with Ford, both engine oil and rear axle lube. THANKS!!!

I just went outside and checked. As of my last oil change, right now my Onan may have regular Mobil 1 synthetic in it instead of Mobil 1 Extended Performance synthetic in it. I can't always find the Extended Performance version of Mobil 1 in the proper weight at auto stores or in bulk at Walmart (much cheaper there).

Whether I have regular Mobil 1 or the EP version of it in my Onan, I always try to use 15W-50 weight in the Onan. I figure that hot weather is the most likely situation I would find myself in for long Onan run-times (for the A/C), so I use my Onan's hot weather recommended multi-viscosity weight of oil in it at all times so as to be ready for the worst-case situations.

FWIW, I've just started seeing adds for what may be a new version of Mobil 1 synthetic. This new formulation is supposedly capable of being safe for engines for up to 20,000 miles. What this means is it's probably pretty good engine oil in general ... so maybe a good candidate for use in our precious built-in Onan RV generators: https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-annual-protection

pnichols wrote:

This is the oil type that I use in our built-in Onan generator...I use the multi-grade weight that the manual specifies for hot weather use.
https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-extended-performance

Which weight? I ask because your rig is newer than ours. Manufacturers change their specs based on old experience and new developments such as better oils. But the print in the Manuals doesn't morph into the latest recommendations. I've seen that with Ford, both engine oil and rear axle lube. THANKS!!!

Dennis12 wrote:
Make sure the oil level is OK and run it. Shut it off once a day and check oil level and then run it

Yep! Other than regularly scheduled maintenance, IMO, that's all you need to do. I like to walk past mine (Onan 4000) once a day and listen to how it sounds when running. I also have a plug in volt meter which digitally reads the output voltage inside my RV at a convenient 120 volt outlet just to make sure the voltage is staying within range. (115 to 125V) Not necessary, but, it makes me feel better.

Chum lee

Make sure the oil level is OK and run it. Shut it off once a day and check oil level and then run it

j-d wrote:
Phil, Please post the specifics of the oil you've chosen for your generator and application. I'm not trying to start an oil debate. LORD Knows there are plenty of them. Just thinking the 10W-40 Valvoline Dino that's in ours now probably isn't the best choice I could make. You think things through and I'd like hear your pick.

This is the oil type that I use in our built-in Onan generator and our little EX650 Honda battery charging generator. For the Onan, I use the multi-grade weight that the manual specifies for hot weather use. (FWIW, in both generators I also use E3 advanced spark plugs to supposedly help reduce fuel consumption and for a slightly "less labored" smooth running sound.):

https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-extended-performance

MitchF150 wrote:
Holly gas consumption Batman! .4 gal an hour.... I ran my Honda 3000i gen hooked up to my house thru a gen switch to run my 2 residential fridges, most lights, computer, tv, microwave and such for about 36 hours during a power outage and it used a whopping 5 gallons of gas...

Huuuuuuhhh???

A 0.4 gallons per hour rate to use a portion of our built-in Onan generator's 33 amps at 120 volts to continuously power our RV's air conditioner during mid-day sun/heat/humidity isn't bad at all - that is assuming that the A/C is continuously running - which it isn't because it cycles ON/OFF depending upon the outside temperatures and the inside temperature that you have it set at.

I'll bet your EU3000i would use gas about at about the same rate (maybe at even a higher rate because it's auto throttle control allows it's RPM to exceed Onan's steady 3600 RPM) to keep the interior of an RV in the sun at around at, say, 75 degrees and 55% humidity in Houston in the summer during the full sun part of the day.

Remember ..... even though an Onan RV generator runs at 3600 RPM all the time .... it's average fuel consumption varies up or down depending upon it's average load while it is spinning at those 3600 RPM. I believe that Honda's portable inverter generators can rotate somewhere above 4000 RPM when they're hit with heavy current demands.

romore wrote:
What generator do you have? I would hesitate to subject a cheap HF unit to that kind of use. Other than going through a lot of fuel you should be alright although you may get tired of listening to it. Change the oil before you go and check the level each time you refill the tank or every five hours or so. DO NOT refuel with the unit running.

I purchased a 4K watt Champion generator about 10 years ago to power a TT I used for hauling off road equipment. I ran 75 feet of power cord and used a piece of plywood to deflect the noise because as you know they are noisy. We boon docked by ourselves so it didn't matter. That generator would run for about 11 hours and then run out of fuel.A few gallons, a quick pull and off it went. It shut off only once for low oil issue, it was leaking oil, my fault. It rolled down a hill once and fell out on the ground from the trailer once. It is beat up,abused and mistreated. It gets clean oil before a trip, fuel with additive to prevent gumming and after sitting for 6 months will start on the first pull.
My coach has an Onan. My employer owned hundreds of Onan generators used to power refrigeration equipment over the road. They are by far the best I have seen. Some of ours ran for weeks on end while being transported over the rail lines hauling perishables. They were fueled at intervals and oil was not checked due to their inaccessibility. They did have low oil safety devices .
Run your generator as long as you care to, it will be fine.

Matt_Colie wrote:
Nurse GJA,

You have a good plan. That Onan should do that in it sleep. Serveral years back, we put 86 hours that was almost continues on one of my Onans, and it didn't care at all. They say that I might need an overhaul (which is little more than a tune-up in their book) at 1000 hours.

So, Go for it. The run will do it good.

Matt

Good to know that a tune up might be in order at 1000 miles. Thanks!