Oil plug size on an Onan Emerald Plus Generator

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Oil plug size on an Onan Emerald Plus Generator

August 24, 2014, 06:06:26 pm

Yahoo Message Number: 148108

Has anyone changed their own oil on the generator? Mine is an Onan Emerald Plus generator installed on a 2001 mid-bath. I have the Onan oil and filter but when I went to drain the oil I found that the oil plug is not what I expected. It is not the typical plug that you can put a socket or wrench on. It is the type that you must insert a tool into it in order to un-screw it. I tried a hex driver, both a 5/16th which is too small and a 3/8th which is too large. Is this the right tool to use or what is it that I need and the size?

Thanks

Kevin Hannah 2001 Mid-bath Poulsbo, WA

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #1 – August 24, 2014, 06:31:17 pm

Yahoo Message Number: 148111

I have changed the oil and filter on my Onan. My LD is 2001 and uses same model generator you have. The pin type screw valve drain plug can be loosened with a set of narrow needle nose pliers. I was able to get it loose with the help of Larry Wade. Carefully grab it at a 90 degree angle and turn counter clockwise as viewed below plug. Use straight 30 weight oil. You can get a good 30 weight at Walmart or buy the expensive Onan oil at most RV stores.

Bob 01 23.5 TK with some goodies in tow.

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #2 – August 24, 2014, 09:05:53 pm

Yahoo Message Number: 148115

I have changed the oil and filter on my Onan. My LD is 2001 and uses same model generator you have. The pin type screw valve drain plug can be loosened with a set of narrow needle nose pliers. I was able to get it loose with the help of Larry Wade. Carefully grab it at a 90 degree angle and turn counter clockwise as viewed below plug. Use straight 30 weight oil. You can get a good 30 weight at Walmart or buy the expensive Onan oil at most RV stores.
Bob
When you said oil and filter did you mean the air filter not an oil filter. I have not seen an oil filter on the gen.
I use 10w30 full synthetic in both of my gens. Onan and Honda 1000. Most small engines like these do not have an oil pump. They are a splash system.

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #3 – August 24, 2014, 09:24:33 pm

Yahoo Message Number: 148116

"When you said oil and filter did you mean the air filter not an oil filter. I have not seen an oil filter on the gen.
I use 10w30 full synthetic in both of my gens. Onan and Honda 1000. Most small engines like these do not have an oil pump. They are a splash system."
I meant oil filter. The Onan Emerald Plus 4000 does indeed have an oil filter and is a v-twin engine. Your Onan must be the later model single cylinder which has no oil filter.

Bob 01 23.5 TK with toys in tow.

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #4 – August 24, 2014, 09:38:10 pm

Yahoo Message Number: 148117

Kevin, the oil drain cover on my Onan MicroQuiet 4000 generator (and probably on your Emerald) is held in place by two Torx T30 socket-head screws. These are six-pointed, but they're star-shaped rather than hexagonal like Allen screws.
The oil drain plug itself takes a standard 9/16" socket. And while I'm at it, changing the spark plug requires a deep 13/16" socket.

Onan neglected to mention any of these tool sizes in their manual, so I pencilled them in on the appropriate pages of my copy. How did I find out the sizes in the first place? Trial and error. I carry sets of Torx and Torx Security bits, as well as other types (Roberts, Tri-Wing, et al.) for just such situations.

Andy Baird

Travels with Andy

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Re: Oil plug size on an Onan Emerald Plus Generator

Reply #5 – August 24, 2014, 11:30:29 pm

Yahoo Message Number: 148122

The drain cock on that generator model is a royal pain.
I purchased a cheap 1/2" socket for a 3/8" drive. I then used a Dremel too with an abrasive disk to cut two slots on opposite sides of it. The 1/2 " socked is just larger than the center pin of the drain cock and the slots let it slide down over and engage the pins. If you put a long extension and ratchet on the socket you can reach down along the front of the generator and easily open and close the drain cock. I also recommend putting a short piece of hose on the cock's outlet so that the oil is delivered below the metal pan that holds the generator. Makes the job much cleaner.

I posted a picture of this socket years ago and then removed it when it grew stale. I found the picture on my computer and will send it to you if you e-mail me at gumm at easystreet dot net.

Linley

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #6 – August 24, 2014, 11:58:08 pm

Yahoo Message Number: 148123

Hi Linley,
Yes, I would like you to send me the picture. I tried the needle nose pliers but that did nto work for me. my email is gkhannah at comcast dot net.

Also, I was the one that referred Ron and Roz Williams to you regarding your LD. They are very happy with it and are planing a trip to Yellowstone in the next few weeks. I am hoping that they come by our GTG on Sept 11th.

Thanks for your help. I really appreciate it.

Kevin Hannah

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #7 – August 25, 2014, 12:06:18 am

Yahoo Message Number: 148125

Hi Bob,
I tried the needle nose pliers but I could not get it to budge. If all else fails I will contact the dealer. I was expecting the normal drain plug. Thanks for your help.

Kevin

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #8 – August 25, 2014, 12:08:51 am

Yahoo Message Number: 148126

Hi,
No, mine has an oil filter and that is what I was trying to say. I have the oil and the oil filter. I will clean the air filter as the unit only has 60 hours on i and lit looks quite clean. Thanks

Kevin

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #9 – August 25, 2014, 12:12:03 am

Yahoo Message Number: 148127

Someone else posted about modifying a socket which I thought was a great idea. Fortunately for mine it wasn't necessary, but I had a master mechanic to help me. Probably couldn't have done it myself.

Bob 01 23.5 TK, Toys in tow

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #10 – August 25, 2014, 12:13:36 am

Yahoo Message Number: 148128

Hi Andy,
Mine does not have the cover that you are talking about. I reviewed several utube videos and I saw what you are talking about but mine just has the drain valve coming through the bottom. It looks like a peacock valve without the wings for turning, like on the hot water tank. Linley seems to have a good suggest and I will try that. Other than that I will call the local Onan dealer and see what they say. Thanks for your help.

Kevin

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #11 – August 25, 2014, 01:13:00 am

Yahoo Message Number: 148130

"When you said oil and filter did you mean the air filter not an oil filter. I have not seen an oil filter on the gen.
I use 10w30 full synthetic in both of my gens. Onan and Honda 1000. Most small engines like these do not have an oil pump. They are a splash system." I meant oil filter. The Onan Emerald Plus 4000 does indeed have an oil filter and is a v-twin engine. Your Onan must be the later model single cylinder which has no oil filter.

Bob

My MH is a 2005 24' LD on the ford, E450 v10. Either LD is using a different gen now or Onan changed the gen. Mine is a single cyl. like you say. No Oil pump or oil filter, splash oiling like a lawn mower or Honda 1000 or 2000 gen.

As for the oil drain. There is a tin cap over the hole where there is a 1/2' plug above that take a 9/16 socket to remove. The screws that keep the tin cap in place are Tork.
If you have a valve with a winged ball valve why not remove the valve and replace with a 1/2" pipe plug.

George

Retired Plumber.

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #12 – August 25, 2014, 01:24:59 am

Yahoo Message Number: 148131

In the years before 2002, LD used the Onan Emerald Plus generator. In 2002 they switched to the Onan MicroQuiet generator. They are fairly different generators. Our 2002 MB has the MicroQuiet, with a typical hex-headed drain plug on the bottom of the genset under an access plate held by two torx screws. While our gensets don't have oil filters, the manuals (easily found online) show an oil filter on the Emerald Plus. Art

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #13 – August 25, 2014, 09:34:52 am

Yahoo Message Number: 148133

"If you have a valve with a winged ball valve why not remove the valve and replace with a 1/2" pipe plug."

George

Retired Plumber

I have never considered the winged valve that big a deal to require replacement. In a way I prefer it to a standard screw in drain plug. I never have to fish a drain plug out of hot oil, like I had to do when the OOPS moment happened while changing oil in cars, motorcycles, etc. It works so I don't mess with it.

I consider the early model Emerald 4000 Plus generator superior to the Micro Quiet in some ways. Have been told by an expert that since it's a twin cylinder it makes sufficient power at lower operating RPMs than the micro quiet, and therefore lasts longer. I like the fact it has an oil filter and pressurized oil system. Vibration is less than the micro quiet as well. Downside is it is much louder. Changing the inside cylinder spark plug requires dropping the generator. Since I rarely run generator this isn't a big issue for me.

Bob 01 23.5 TK with toys in tow.

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #14 – August 25, 2014, 09:34:48 pm

Yahoo Message Number: 148148

Hi All, I used Linley's solution this afternoon and it worked. I did the same as he did and cut two slots into the 1/2" socket which allowed the drain cock pins to fit into the two slots. From there it was fairly easy but it is a cramped space and with patience it is workable. Changing the oil filter was a breeze.

Thanks all that responded. I appreciate all of you.

Kevin Hannah

Re: Oil plug size on an Onan Emerald Plus Generator

Reply #15 – August 26, 2014, 01:26:14 am

Yahoo Message Number: 148156

Oran's Emerald and MicroQuiet generators have little in common, othe than the Onan name.
The Emeral is at twin cylinder engine that spins at 1800-RPM. It has a pressurized oil lubrication system.
It is a very durable generator, with an average life 50-100% longer than a MicroQuiet and is rebuildable.

The MicroQuiet has a single cylinder engine that spins at 3600-RPM. It uses a splash lubrication system, without a filter. Basically it is a lawn mover engine. Use it up, throw it away.
Its advantage to the RV owner is it's superior sound damping. Most of use will never use it enough to wear it out.

BTW, Onan sells a tool for the Emerald's oil drain petcock. It looks similar to the DIYsolution mentioned previously.

Larry

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