Genset Initial Starting Eratic

[gksmith]

I have a 2002 Leisure Travel camper van with an Onan MicroLite 2800 GenSet. The unit starts fine, BUT for only for a few seconds and then it dies. If I wait a minute or two, it will restart again and run for a longer time, maybe 15 seconds and die again. If I repeat the procedure with a wait time in between, it will again start and run even longer before dying. However, usually by the fourth attempt it will start and keep running. When it keeps running, it works just fine and does not die--everything seems just fine. But this whole procedure has been going on repeatedly during the whole season.

What is causing this problem and how can I resolve it?

[BBQ]

.

Google Red Rover Onan Trouble shooting guide

[hbn7hj]

I would start with fuel as in fuel pump or cracked fuel line.

[gksmith]

Fuel was my thought, too, but there is a good stream of gas from the fuel pump. I would like to change the fuel filter, but everything is so tight, that I cannot do it. I even found a YouTube video that started to change the filter, got it off, and he could not get it reinstalled. He closed the video saying he thought he would have to use a Sawzall to cut off the front portion of the GenSet panel in order to get to the bottom clamp for the filter. I can't even find the fuel line going to the GenSet--the clearance underneath is so tight.


I failed to mention that after a few attempts of starting the GenSet, the amount of time it runs will increase, until the final attempt when it keeps on running. Usually if it runs for a minute or so, it keeps on running. Hence, I have wondered if was something connected to building up voltage not quickly enough to keep it running, rather than a fuel problem. However if I try too quickly between attempts, it will not start at all, but if I wait for a minute or so, it will start for a few seconds or more. So far it has never failed to keep running, but it is frustrating to have to try up to a dozen times.

Do these comments give you any additional insight or ideas regarding the problem.

[gksmith]

I have downloaded and saved the troubleshooting guide. The main possibility from the guide is an air leak in the fuel line. But I can't even find the line! How do people work under their Class B motorhomes??? I guess I will have to buy some ramps, but I am not sure they will provide enough extra clearance in the middle of the chassis.

[Hondo]

Start by changing the inline fuel filter, cheap & easy.

[BBQ]

.

There is a vent tube that goes to the carburetor.
Make sure it is not blocked.

[gksmith]

Hondo - It may be cheap, but it isn't easy. One cannot get to the bottom of the filter to reattach the clamp--at least I can't. There even was a YouTube video where the presenter found the same problems and gave up on the video, saying he was going to cut out the front of the GenSet enclosure.

[shelleyvanter]

1. Check before starting: check battery connection; check oil adequacy (observe oil gauge, between maximum and minimum); check diesel fuel (diesel should be selected according to actual ambient temperature).

2. Insert the key into the boot disk, then go to the "run" file, observe the diesel engine display table (figure 1 / 2) and start if the cylinder thermometer and the oil thermometer are normal (not to the red area); if not, The corresponding sensor damage. Note: the oil pressure meter because of no pressure before startup, can not be in the normal zone, do not affect the start.

3. Engine: rotate the speed switch (figure 1) to "low", then rotate the unit key to the "start" file, release the key after starting.

why not directly ask your genset supplier for help to solve the problem?

[Hondo]

You m ight have to drop it then to gain access.

[hbn7hj]

Should you have an Onan you need to be capable of removing it and working on it. The charge for someone else doing it is $200-$250 plus repair costs.

Either do it yourself or pay the man. The Saws All idea is absolutely ludicrous.

I expect someday there will be a replacement but it isn't here yet or even on the horizon. The environment down there is tough to live in.
Harry

[JohnnyFry]

An additional possibility to consider is tarnished slip rings. The slip rings carry the DC excitation voltage to the rotor. This excitation is what causes the voltage to build up and is controlled by the voltage regulator. As the rings tarnish their resistance increases and inhibits AC voltage build up. On the initial start ups, the scraping of the brushes may clear oxidation on the rings sufficiently to allow voltage build upon later starts. The voltage regulator raises excitation voltage to compensate for the increased resistance. If this goes too far the voltage regulator module becomes damaged and must be replaced. Unfortunately, polishing the slip rings and replacing the brushes requires the generator to be dropped and partially disassembled.

[Doneworking]

gksmith, if it was mine I would try getting it going, let it run an hour or so with no load, introduce a good continuous load like the AC with the thermostat set low as possible so as to make sure it never reached that temperature and let it run for ten or twelve hours and see if that helps.

These generators are really designed to be used and used. We RVers tend to run them for relatively short periods of time and call it a day. Sometimes on a trip of several hundred miles this time of year, I run mine under an AC load all day while going down the road, not to stay cool but to just use the genset and give it a really good workout.

Paul

[Gary Mn]

I have read that low oil level can affect the run time and there is a sponge like filter on the outside of the unit that can become plugged.

[lgpacker]

It may be that the oil pressure switch located in the oil pan is stuck and signaling incorrectly that there is insufficient oil and therefore won't allow the engine to run after the start button is released. If the engine runs while the start button is pushed but dies after release, that is a good indicator of this problem. Flight Systems troubleshooting guide goes over this at Troubleshooting and Cross-Reference Guides | Flight Systems, Inc in their onan generator, section on voltage regulators and control boards.

I'm sure that is the problem with my 2000 LTV but it will require dropping the genset and spending dough on a genset that I find I have no need for anyway. I might get it repaired when it's time to sell. Until then, I'm just fine without it.

[gksmith]

Originally Posted by JohnnyFry

An additional possibility to consider is tarnished slip rings.

I have wondered about the problem being something rather than fuel, but I confess to being very unknowledgeable regarding generators. Can this condition be tested? The voltage regulator was replaced about a year ago by a Cummins repair station. It was quite pricey, so I would hate to have to replace it again! The replaced voltage regulator did solve the problem I had at that time, which was that it often would run only when the start switch was held down. But the current situation, where the unit will start properly for a few seconds and then quit until repeated several times for it to run continuously, started a month or so ago. Are tarnished slip rings a situation where it could or would have been tested for?

Another poster suggested running the unit under load for ten to twelve hours. Would this possibly help the problem?

Thanks for your input!

[RT.SS]

Originally Posted by gksmith

Are tarnished slip rings a situation where it could or would have been tested for?

Another poster suggested running the unit under load for ten to twelve hours. Would this possibly help the problem?

Thanks for your input!

You can test the slip rings without dropping the genset, but could be hard due to its location. Pins 9 and 10 from the Voltage regulator goes to the block brushes. You can measure the resistance between these pins. The resistance reading should be between 22-28 ohms (reading includes resistance of rotor, brushes and slip rings). A much lower resistance indicate partially shorted rotor. A higher resistance (up to 200-300 ohms) indicates dirty slip rings. Several meg ohms or Infinity reading indicates open rotor or worn out brush.

Probably wise to check things first before running your genset for that long. Tarnished slip rings will cause the Voltage regulator to work harder and can cause premature failure, not to mention slip rings will run hotter and will result to further deterioration of their contact surfaces.

[gksmith]

It is time that I post the resolution to the problem I had with my genset not starting easily. I finally took it to a Onan/Cummins repair facility. It cost me what felt like a fortune, but it was only a choke setting. The genset had to be dropped in order to access the choke to adjust it! Never in my life have I had to pay close to $600 to have a choke adjusted on a vehicle, but I never had a Class B motorhome before! Oh, the price you have to pay for the compactness of Class B!

We have not taken the coach on the road since the work was done, but I have started and run it monthly as recommended with no problems. It was interesting to have so many suggestions be made, where the solution was something not suggested and also so simple, but yet so difficult to accomplish!

Thank you to all that made suggestions! There is always something more to learn or consider.

[Doneworking]

The prices they get for working on these things is just nuts. If I were building my own rig like some of the folks on this forum have done I think I would get a remote control inverter Honda generator and just say bye bye to Onan.

We thought about buying a small (22-24 foot) travel trailer a few years ago and pulling it with our Jeep GC. It has the hemi and a towing capacity of 7200 pounds and so that wouldn't be a problem with one of the newer light weight trailers. In our thought process, I just assumed I would slap one of those super quiet Hondas on that trailer and forget about the Onan troubles. It is just ridiculous that virtually all Bs use those suckers. They are expensive to buy, maintain and are LOUD.

The reason, apparently, is that none of the other manufacturers make a rv specific generator. The market is just too small. Having owned three Class Cs over the years, I think the 4000 watt models they generally use are located in positions that makes every thing service wise so much easier.

Yep, we pay a BIG price for Bs for their Little space just like gksmith stated.