Generator

Changing the oil can be accomplished with the generator in place. Draining is fairly straightforward, but re-filling it can be a challenge. Most people use some kind of pump to get the oil into the dipstick/filler hole.

Accessibility to perform non-routine maintenance seems to be vehicle specific, with many models of RV requiring dropping the unit to do nearly everything except change the oil.

Here is the link to the manual, in case you didn't receive one with the RV itself. It doesn't address accessibility per se, but does show the removal process for typical installations.

Onan 2800 Service Manual

What make of Class B did you buy? If it's a Pleasure Way, there are a couple of black snaps on the bumper, one on each side of the license plate that allow you to drop a panel and see the generator and access it. But, I'm kind of going by memory 'cause we sold our PW awhile back and we now own a Class C, so I may not have it stated very well.

It is likely you have an Cummins/Onan 2500Kw LP from your description. It is serviced by skittering under the RV. Helps to put the rear end over a depression to get a bit more room.

The generator is in a light green fiberglass case. The rear facing part has a removable cover. Release the two latches and lift the cover up. It will come off. Oil check is the yellow do-dah. IRRC, check warm to hot. Unscrew, wipe clean, and just set the dipstick on the fitting. The level should never be over the hashed marked area. Since the oil expands, I kept mine in the low to mid range of the band.

Check the air cleaner to be sure it is properly seated. They can work loose or be improperly installed.

There's a circuit breaker reset inside the cabinet.

Oil drain is underneath the cabinet.

DO NOT OPERATE WITHOUT THE COVER IN PLACE!!!! Needed for cooling.

DO TRIPLE CHECK THE FIT AND LATCHES WHEN INSTALLING THE COVER!!!

IRRC, service interval is check daily if use 24hrs a day; maybe every 20 hours if not; change oil every 100-150 hours after break-in.

If you are going to be operating where the temperature is routinely below 35ish, you want 5W30. Above 35ish you can use 15W40. I use 15W40 Onan oil as I'm in Texas and rarely would I be operating in 30ish temperatures but do operate in the above 80 range.

Exercise it about every 4 - 6 weeks. LP ON, crank her up; let her stabilize; slowly add a couple loads (A/C is great); run about 15 minutes; loads off and let it cool down 5 minutes; turn off.

Since it is an LP (B's rarely have a diesel due to their size and weight) it's not going to be sensitive to gumming up and crapping up due to bad diesel. The LP downside is that they start having trouble when the temperatures get down in the 20s as they depend on LP vapor. Vapor is harder to come by in cold weather!!!

Do Google ONAN manuals and download one or print it out if you don't have one. Lots of good poop in the manual!!!

Hope this helps... good luck and enjoy!

Old Crows

It will only be propane if it's a diesel, otherwise it's gas, and the carb
gets gummed up pretty easy from lack of exercise. The carb. can't be rebuilt, so if it's running keep using it, and exercise per the manual.
Type, year, and model of your Class B would be helpful.

I bought a class B that hadn't been used for a couple of years in October. The generator is in the middle underneath and doesn't start. I took it to an RV dealer to do some other camper stuff and asked him to see what he could do with the generator - nothing because he doesn't have a lift. So, I took it to a Cummins place and they lifted it but couldn't drop the generator...they would have to cut it out due to rust. So, I chose not to have it repaired (estimate was $1,500 - $2,000 to repair, $4,500 to replace).

Old Crows wrote:
It is likely you have an Cummins/Onan 2500Kw LP from your description. It is serviced by skittering under the RV. Helps to put the rear end over a depression to get a bit more room.

The generator is in a light green fiberglass case. The rear facing part has a removable cover. Release the two latches and lift the cover up. It will come off. Oil check is the yellow do-dah. IRRC, check warm to hot. Unscrew, wipe clean, and just set the dipstick on the fitting. The level should never be over the hashed marked area. Since the oil expands, I kept mine in the low to mid range of the band.

Check the air cleaner to be sure it is properly seated. They can work loose or be improperly installed.

There's a circuit breaker reset inside the cabinet.

Oil drain is underneath the cabinet.

DO NOT OPERATE WITHOUT THE COVER IN PLACE!!!! Needed for cooling.

DO TRIPLE CHECK THE FIT AND LATCHES WHEN INSTALLING THE COVER!!!

IRRC, service interval is check daily if use 24hrs a day; maybe every 20 hours if not; change oil every 100-150 hours after break-in.

If you are going to be operating where the temperature is routinely below 35ish, you want 5W30. Above 35ish you can use 15W40. I use 15W40 Onan oil as I'm in Texas and rarely would I be operating in 30ish temperatures but do operate in the above 80 range.

Exercise it about every 4 - 6 weeks. LP ON, crank her up; let her stabilize; slowly add a couple loads (A/C is great); run about 15 minutes; loads off and let it cool down 5 minutes; turn off.

Since it is an LP (B's rarely have a diesel due to their size and weight) it's not going to be sensitive to gumming up and crapping up due to bad diesel. The LP downside is that they start having trouble when the temperatures get down in the 20s as they depend on LP vapor. Vapor is harder to come by in cold weather!!!

Do Google ONAN manuals and download one or print it out if you don't have one. Lots of good poop in the manual!!!

Hope this helps... good luck and enjoy!

Old Crows

2800 is gasoline 2500 is propane. opp said 2800

You have pretty much gotten the word on the under chassis Onan 2800 microlite. Major service involves taking the generator down and there are Onan service centers all over - there is a list on the Onan-Cummin's website. Regular maintenance can be done with the generator in place but you have to crawl under and access it. Changing or adding oil involves pumping oil up from the oil bottle and then down into the fill hole. There is a hand pump sold for boat motors that attaches to a standard oil bottle that makes this easier to do (find it in a marine store or Walmart in Sporting Goods marine section). Onan suggests exercising the generator every month for two hours under at least half load - 1400 watts. This is very important and will save more serious costly maintenance later.

It is made to run with up to 15 ethanol gasoline but it can still get gummed up. Add some ethanol treatment to your gas tank and when you exercise the generator you will be putting the treatment through at the same time. I do this when I winterize and then through the winter when I exercise the genny, I run the treatment in with the gas.

If you don't want to change the oil yourself, any RV shop will do it for you. Some have asked their mechanic to do it - but you will likely have to explain and show them where it is. It takes only one quart of oil. The type varies and there is a chart in the Onan 2800 manual.

gerrym51 wrote:

Old Crows wrote:
It is likely you have an Cummins/Onan 2500Kw LP from your description. It is serviced by skittering under the RV. Helps to put the rear end over a depression to get a bit more room.

The generator is in a light green fiberglass case. The rear facing part has a removable cover. Release the two latches and lift the cover up. It will come off. Oil check is the yellow do-dah. IRRC, check warm to hot. Unscrew, wipe clean, and just set the dipstick on the fitting. The level should never be over the hashed marked area. Since the oil expands, I kept mine in the low to mid range of the band.

Check the air cleaner to be sure it is properly seated. They can work loose or be improperly installed.

There's a circuit breaker reset inside the cabinet.

Oil drain is underneath the cabinet.

DO NOT OPERATE WITHOUT THE COVER IN PLACE!!!! Needed for cooling.

DO TRIPLE CHECK THE FIT AND LATCHES WHEN INSTALLING THE COVER!!!

IRRC, service interval is check daily if use 24hrs a day; maybe every 20 hours if not; change oil every 100-150 hours after break-in.

If you are going to be operating where the temperature is routinely below 35ish, you want 5W30. Above 35ish you can use 15W40. I use 15W40 Onan oil as I'm in Texas and rarely would I be operating in 30ish temperatures but do operate in the above 80 range.

Exercise it about every 4 - 6 weeks. LP ON, crank her up; let her stabilize; slowly add a couple loads (A/C is great); run about 15 minutes; loads off and let it cool down 5 minutes; turn off.

Since it is an LP (B's rarely have a diesel due to their size and weight) it's not going to be sensitive to gumming up and crapping up due to bad diesel. The LP downside is that they start having trouble when the temperatures get down in the 20s as they depend on LP vapor. Vapor is harder to come by in cold weather!!!

Do Google ONAN manuals and download one or print it out if you don't have one. Lots of good poop in the manual!!!

Hope this helps... good luck and enjoy!

Old Crows

2800 is gasoline 2500 is propane. opp said 2800

Darn, yes he did..... Scrub the LP comments. Not had a gas genny in an RV but would expect carb problems unless one is fastidious about fueling and run the carb dry before shut down based on my other generator and OPE.

They generator runs off the fuel tank, so you can't run it dry unless a fuel cut-off valve is installed between the gas tank, and gen-set. The fuel cut should only be used if it its impossible to exercise the the generator monthly, as it still needs to have the moisture evaporated internally.