Onan RV Generator Set

Onan Circuit Breaker

Originally posted at http://roadtrek210.blogspot.com/
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The original blog includes disclaimers, etc. See the end of this post for a copy of those disclaimers....


Update September 5, 2021:
Added troubleshooting information.

Update April 5, 2018:
Added power decrease information for altitudes above 500 feet (163m) above sea level. Updated miscellaneous info and added air filter photo.

Comment added February 1, 2018:
Over at a FB group: "Onan update: ok... so went to check oil level this morning and low and behold there is oil all over driveway........... Matthew at Roadtrek said one should not drive while running generator.... I was told that was good way to exercise it and not disturb my neighbors."

Here's my comment: "I know it is inconvenient, but Onan recommends a physical inspection of the generator before running it. While that may be unrealistic given the under mount, frequent inspections (or at least once a month before that two hour exercise) might be prudent."

Original Post, updated:

Oil fill cap and dipstick - Loosened to show threads

Our RT included the optional gasoline powered Onan 2.8 kW generator set.  I'd read some negative comments about generators in RVs, including Roadtreks. At one time the president of that company stated that the generators were their number one maintenance issue, or words to that effect.

I was concerned. So I read all of the Onan-Cummings documentation including the "Operator Manual" and "Installation Manual" and I decided to follow all of the recommendations. One concern I had was changing the engine oil. The generator is mounted under the vehicle and seemed to be difficult to get to. It really wasn't that difficult and this post includes photos of how I did it. 

I have also obtained a copy of the "Onan RV Genset Service Manual KV KVC KVD".  I've read and studied them all. 

This blog indicates that I can do some basic service tasks. For example, I have been able to do my own engine oil changes. This wasn't as difficult as I expected.  In fact, my experience with this generator has been a very good one for 5-1/2 years, as of September 2021. I do exercise the generator about monthly, I do check the oil level and I am inclined to replace the oil level at a shorter interval. I view the intervals for service in the manuals as the "maximum".  That's my perspective and I do realize others think these are merely "suggestions".  

I'm not yet at 150 hours, but I will be replacing the air filter in early 2022 and I'll probably replace the fuel filter and the spark plug at the same time.  I'm a "preventative maintenance" advocate because I really don't like breakdowns.

Here are some Onan recommendations for my generator set, which is a model 2.8KVFA26100K "IMPORTANT - Refer to your genset manual for the "official" manufacturer's recommendation for your genset. This does not relieve you of the responsibility for proper maintenance of your genset."

1. The gasoline powered generator on my Roadtrek should be exercised two hours per month. Onan states that a two hour continuous run is better than several short duration runs. 
2. Onan states that the generator should be exercised with a half load. 
3. Onan recommended a "break-in" period with specific instructions. I followed them. The Onan manual is very specific about loading and oil viscosity during this period. 
4. Onan recommended single weight oil over multi-viscosity. However, it also recommended several different oil viscosities as determined by minimum and peak ambient temperatures. 
5. Onan recommends a gasoline additive. 
6. Onan recommends an initial oil change at 20 hours, and thereafter at 100 hours, unless used under dusty conditions. In dusty conditions the oil is to be changed every 50 hours. 
7. Onan recommends a general inspection every day of use.
8. Onan recommends checking the engine oil every 8 hours of use. 
9. Limit the cranking time with specific duration pauses. 
10. Set the "altitude adjustment" to match the current altitude. 
11. Onan recommends "Before the first start of the day....inspect the genset as instructed under CONDUCTING GENERAL INSPECTIONS..." I do as that list recommends. Actually easy.

I've followed Onan's recommendations, with one exception.

1. I don't change the altitude adjustment from day to day. More on that later in this post.  

Some things I do which might contribute to my [good] experience:

1. I followed the "break-in" recommendations.
2. I add "seafoam" gasoline additive to the RT210 tank. I do this during fill-up when I expect to run the genset on that tank of gas. I purchase the seafoam in a large, one gallon container to save money. One gallon has made it for three years.
3. I do exercise the generator frequently and attempt 1-1/2 to 2 hours per month.
4. I do use the recommended oil viscosity and per Onan's manual I use single weight oil where practical.
5. I change the oil with seasonal changes, whether I've reached the number of hours or not. I travel from below freezing temperatures to 100F with the anticipation of using the generator. 

My longest period using the generator was overnight in New Mexico with a low of about 25F. I ran it all night. Not a problem. The only issue I have experienced to date (since December 2013) was running it to exercise it at temperatures below 20F. It did start, but it had the "break in oil" in it which might have contributed to the reluctance to start.

Why exercise the genset drive? 

The manual for my Onan generator set states "Exercising the genset drives off moisture, re-lubricates the engine, replaces stale fuel in fuel lines and carburetor and removes oxides from the electrical contacts and generator slip rings. The result is better starting, more reliable operation and longer engine life." (emphasis is mine).

Reaching the genset to do maintenance

Of course, to change the oil or to set the altitude adjustment requires getting to the genset. In my case it is mounted under the vehicle.  Initially I tried to do this in cold weather while wearing a moderate weight coat. It didn't seem possible. However, by removing the coat I was able to easily slide in from the side of the vehicle. Here is what I determined:

1. Wear light weight clothing.
2. Put a "blue" fiberglass tarp under the rear of the vehicle. This is "slippery" and makes it easy to slide in or out on one's back and with little effort. 

Troubleshooting, per Onan Service Manual

The following does provide some ideas about possible causes for common problems. For complete details, including diagrams and corrective actions for these and other problems, refer to the Onan Service Manual. Onan Factory WARNING: "Many troubleshooting procedures present hazards that can result in severe personal injury or death. Only trained and experienced personnel with knowledge of fuels, electricity, and machinery hazards should perform service procedures. "

1. Engine does Not Crank:

• Open control fuse F1.
• Insufficient cranking voltage.
• Start solenoid (K1) not energized.
• Starter (B1) not energized.
• Will engine crank from the start-stop switch mounted on the generator?

2. Engine cranks but does Not Start:

• Restricted fuel supply.
• Faulty ignition due to worn or fouled spark plug.
• Sticking choke or carburetor mixture screws incorrectly adjusted.
• Fuel pump (E2) not working.
• Governor linkage stuck or binding.
• Oil level switch (S2) closed due to low oil level or defective switch.

3. Engine Starts But Stops When Start Switch is Released:

• Low oil level.
• Defective low oil level switch. 
• No field flash voltage.
• Defective generator, control assembly or voltage regulator VR1.

4. Engine Starts and Runs, Then Stops. Generator Set Immediately restarts or after Cooldown:

• Fuel level is below genset set fuel pickup tube (about 1/4 tank).
• Oil level is low.
• Faulty choke operation. 
• Vapor lock from high ambient restrict airflow. 
• Contaminated or incorrect fuel. 

5. No AC Output. This may cause Generator to stop when Start Button is Released:

• Open circuit breaker. 
• Open circuit between stator connections Q1 or Q2 and voltage regulator.
• Open circuit between battery Pos. (+) and voltage regulator pin 7 for field flash.
• Brushes not making good contact. 
• Slip ring surface is rough or pitted.
• Capacitor C1 shorted.
• Defective generator, control assembly A1 or voltage regulator VR1.

6. Engine Runs Rough:

• Dirty air or fuel filter. 
• Contaminated fuel.
• Lean fuel mixture.
• Faulty ignition, due to worn or fouled spark plug or ignition wire.
• Carburetor icing.

7. Engine Lacks Power:

• Dirty air filter. 
• Restricted fuel flow.
• Exhaust system blocked or restricted.
• Carburetor air preheater set incorrectly.
• No load speed set too low.
• Incorrect fuel mixture.
• Incorrect valve lifter clearance or worn valves.
• Excessive engine wear.

8. Engine Hunts or Surges:

• Fuel supply problem.
• Incorrect fuel mixture.
• Governor problem.
• Carburetor icing.

9. Engine Shuts Down and Will Not Restart:

• Low oil level.
• Low oil level switch defective..
• Worn spark plug.
• Flooded fuel system.
• Choke not opening.
• Faulty ignition system.

10. Engine Runs on After Shutdown:

• Fouled spark plug.
• Engine carbon build-up.

Changing the oil or checking the oil level

This is relatively easy in my 210P. There are two slide "tabs" which hold a removable access cover in place. Pushing them both up releases the cover. This provides access to the "oil fill cap and dipstick."

Removing the cover also provides access to the "altitude adjustment."

Tools required to change the oil in my genset:

1. 14mm socket set
2. Torque wrench 21 lbs-ft (27 N-m) if available. 
3. Small crescent wrench (less than 6 inch); OPTIONAL
4. Small plastic funnel

Why the crescent wrench? I couldn't get enough torque with my left hand to rotate and loosen the "oil fill cap and dipstick." So I gentlyused a small 4 inch crescent wrench to provide some leverage. But that's a plastic cap, so I had to be careful.

Onan oil recommendations - Check your manual before selecting

Onan Recommendations per the manual for my Genset

Steps for oil change (see photos):

1. Run the genset as recommended by Onan to heat 
2. Slide the access cover latches up. CAUTION. Some components will be hot!
3. I first remove the "oil fill cap and dipstick." I do this because if I first dump the oil and then have difficulty and can't remove the oil cap, I'll have a generator with no oil. I would be committed and unable to run the genset until I found a way to remove the oil cap and add the required oil. Of course, accidentally running a generator without oil is a certain means of destruction. 
4. Then I place a 1 quart container under the "oil drain plug." An old coffee container works well.
5. Loosen the "oil drain plug" and let it flow into the container beneath.
6. After the oil has drained tighten the drain plug (recommended 21 lbs-ft (27 N-m) per my Onan manual.
7. Insert the small plastic funnel.
8. Gradually pour fresh oil into the funnel until the proper amount is in the generator. In my case, 1 quart of 30W for temperatures "32F (0C) and higher." All according to the Onan manual. 
9. Insert the "oil fill cap and dipstick" and confirm the oil level is proper. 
10. Tighten the  "oil fill cap and dipstick."
11. Replace the access cover.
12. Dispose of the old oil responsibly. There are numerous recycling options available.

Altitude adjustments and Power versus Altitude
Onan states that power decreases at higher altitude (this is per their manual):

• Up to 500 feet (162 m) above sea level = 2800 watts (rated power)
• At 2500 feet (762 m) = 2604 watts
• At 5500 feet (1676 m) = 2310 watts
• Above 5500 feet = 2310 watts decreased by 98 watts for every 1000 feet (305 m).

Onan recommends setting the adjustment for the current altitude. I've left it in the position originally set by the Roadtrek factory, or the manufacturer. My bad? I've never use it above 4500ft or lower than 300ft above sea level.

Photos

Onan nameplate - This is the model that is in my Roadtrek

Oil fill cap and dipstick, after loosening

Oil drain plug

Loosening the oil drain plug

Draining the oil

Oil draining into the coffee can

Oil fill point, with "oil fill cap and dipstick" removed

Plastic funnel inserted into oil fill point

Altitude adjustment

Air filter (Onan manual recommends "perform more frequently when operating in dusty environments":

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