Troubleshooting an RV generator set requires that you think like Sherlock Holmes and ‘deduce’ things so, get your hat, curved pipe (and maybe a beer) and we’ll see what we can do. First, your generator has to have a problem. The first great rule is “If it ain’t broke, don’t fix it”. If it is broke, then we get to play around and scatter parts all over the lawn. Use your senses to help with the problem. Sight, smell, hearing, touching, etc: Troubleshooting is greatly facilitated if you have the service/overhaul manual for your generator. They are available from the manufacturer, a local dealer or on the internet. The second great rule is “Read (and understand) the book”.
The third rule of T-shooting is “determining what type of problem you have”. Ie: Don’t replace the fuel pump if you have forgotten to install the battery. You will troubleshoot differently for operational, mechanical, electrical, or fuel problems. That being said, the majority of T-shooting should be done on a Go/No Go basis. That means picking a point in a system and determining if you have the correct parameter or not.
Lets take a common problem and see if we can troubleshoot it. The engine cranks but won’t start. It ran yesterday at the wilderness campsite, so there is a problem. Remove one spark plug and reconnect the plug to its wire. Crank the genset – SEE sparks?? Yes/No – YES. So it is probably something else. Sniff the spark plug area – SMELL gas?? Yes/No – NO. Aha, a possible fuel problem. Lets go to the middle of the fuel system and test there. Disconnect the fuel pump wire and get a jumper wire and connect it from battery positive to the fuel pump hot wire. Do you get any pumping sounds?? Yes/No — YES, but it’s really NOISY. OK, the pump is probably good so let’s get a gallon jug of gas and connect it to the input side of the fuel pump. Try the jumper wire again. Hey, the pump ran and then got quieter and seemed to run slower. Before you drop that 70 gallon gas tank to change the rubber fuel lines, turn on your ignition switch and see if you have over ¼ tank of fuel -Yes/No — NO. SOF (Statement Of Fact) — RV genset fuel lines go in the top of the fuel tank but stop a few inches (1/4 tank) from the bottom. This lets you run the generator for wilderness camping and still drive back to a service station (RV’s are hard to push). You have just troubleshot for about an hour and finally found it. You have also ADDED to your knowledge of the generator system so all is not lost and I know it won’t happen to you again, don’t I? You will notice that we didn’t disconnect any pressurized fuel lines and test them. If you have to open a pressurized fuel line just make sure an extinguisher is very close and the wife has paid up your insurance policy.
Next week – genset control T-shooting, get your multi-meters ready. — You don’t have one?? Why not?
Generator Jim
Karen
We bought a 1983 Holiday Rambler class A motorhome and all the generator wiring has been torn out! How do we find a wiring schematic so we can rewire it properly? Thank you!
richard gould
Hi, I have 1993 dolphin camper with a 2.8 onan micro lite generator, I ran it a couple of day’s ago and everything worked fine,air cond. microwave etc. today I went out and started the generator and nothing work’s,it is not putting out any current, I checked all fuse’s and cuircut breaker’s and found nothing, all work’s well when plugged into the house. what could I be missing, maybe a fuse I can’t find? Thank you so much. Richard.
Greg
Hello Jim. You sound like you know your stuff so I have a problem. I have a 1987 4.0 BGE. I bought the motor home a year or so ago and the generator worked fine but, Someone had “HOTWIRED” it somehow. It had been wired to crank and run using a house light switch. The problem was that the starter stayed engaged the whole time the Genset was running. Not knowing this it melted the starter. After that I worked of town for 10 months and when I returned home I replaced the starter. Not knowing how to check anything electrical, I wired it up the same except i wired the starter on a seperate push button. It cranked right up and runs perfect. Now it puts out a whole 3 volts! I have cleaned the slip rings and brushes. No change. I am not electrically inclined but I am mechanically! I checked the voltage at the brushes and it’s about the same 3V. I guess the circuit board is fried but I dont understand why it worked so well before. All that is exactly as it was before I shut it down. It was working great and I shut it down and it would’nt crank. That’s when I found the starter fried.
Now, I touched 12 volts to the brushes. One side, it started putting out 140 volts, the other side no change. It runs everything but the A/C. It seems to put out voltage but no amps. The microwave runs but is very weak. I am checking the voltage in the junction box at the genset and also a couple outlets. It’s the same at all outlets. Can you please help?
stefan
I would think it would be easier and safer than walking around with a container of gas to just disconnect the output side of the pump and see if you’re pumping fuel.
Bob
Do you plan an article on replacing hydraulic hoses on the slideout/jack systems? I have several leaks on my HWH system.