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RV Doctor ColumnRV Doctor #335 Dear RV Doctor, I have a 6,500-watt gas Onan generator that starts and runs on the starter but quits when you release the switch. I have tuned it up, replaced the fuel pump (not up to par) and after much searching, found the specifications for the points, etc. Does this engine have a ballast resistor (like the old Dodge chassis')? And where would it be located, in the coil? Larry Westfall, (Avon Park, FL)
Larry, I haven't seen this problem in quite some time. Indeed there is a resistor in that start circuit that, if faulty, will result in your specific symptom. On newer units that symptom usually means a circuit board is faulty, but on your unit there is a resistor located on the generator end (the right-hand side) of the unit as it's positioned in the compartment. There is a removable shroud covering the brushes and other generator components on that right-hand side. Disconnect the battery to the generator and look under that shroud. You should see a metal spring clasp that holds the shroud in place. Release the clasp and the shroud can either be lifted off the unit or slid to the right to gain access to the resistor. The resistor is located under the upper support bracket closest to you. It will have two spade connectors on it. It will be necessary to remove the resistor (one long screw through the center) and replace it with one of the same rating. Your parts book for that generator should reveal the actual part number you need. I've never fully understood why this resistor burns out periodically, but a new one will have you cranking that unit in no time.
Dear Gary, I have a water heater that seems to be leaking although I cannot actually see it leaking. But I have a towel placed close by the heater and it does get wet. All the water lines seem okay. Can the water heater tank be soldered? Is there any kind of cement to seal the leak once I get the tank out? The water heater is only two years old. Thomas Honeywell, (Dallas, PA)
Thomas, you are seeing the negative effects of electrolysis inside the water heater tank. Electrolysis, sometimes called galvanic corrosion is quite common in RV water heaters. Whenever water passes through a container, the minerals suspended in the water supply begin to react inside the inner tank of the heater. Even microscopic particles contribute to this natural phenomenon. Atwood water heaters are glass lined while Suburban's water heaters are metal, but come equipped with a sacrificial anode rod to offset the effects of this electrolysis. But when the heater is exposed to higher concentrations of mineral content, the corrosion inside becomes accelerated. This results in tiny pinholes all the way through the tank wall. But it does seem odd that your tank has corroded through in just two years. If your water heater is manufactured by Atwood, the inner tank is replaceable. If you have a Suburban water heater, it is not; a new water heater is in order. Be sure to check all the fittings and components attached to the water heater tank before condemning it, however. At the rear of the heater (inside the coach) you'll find the cold inlet and the hot outlet and perhaps an anode rod. Threaded into the front of the heater will be the pressure and temperature relief valve, drain valve/plug, gas control assembly (pilot models), and on some models, an anode rod. If your heater has an electric heating element option, that too is threaded into the inner tank. Be sure to physically check each fitting that may be leaking. Leaks at the above-mentioned fittings/components may eventually find its way to the floor area inside the RV. Additionally, if you have the motor-aid option, whereby coolant from the engine radiator is passed through the heater to heat the stored water, look at those connections closely. Though they are not actually threaded into the inner tank, they could still leak causing you to believe the leak is inside the water heater. Water heater inner tank replacement on an Atwood heater is relatively easy for the handy do-it-yourselfer, though it does mandate a complete removal and disassembly of the heater. Replacing a like-sized Suburban heater is straightforward and again, easily performed by the handy RVer. Both tasks, however, require the LP line to be disconnected and reinstalled so be sure you understand the dynamics of checking the coach for LP leaks if you attempt either.
Dear Gary, I have read several articles on how to sanitize the fresh water tanks, however, first you have to be able to get the solution inside the tank. I have not been able to find any way to pour the solution into the tank other than through the hose connection. Do they make a kit to pump the solution into the tank through the hose connection? There has to be a way. Am I being a bone head and missing something simple? Brian Stebbins, (Pioneer, CA)
Brian, the easiest way I've found to sanitize and chlorinate the fresh water tank on any motorhome is to mix your own solution of common household bleach. I recommend a ratio of 1/4-cup of bleach for every 15 gallons of tank capacity. The first step is to drain and flush the fresh water tank with clean water. Don't forget about the tank on the water heater! There's no need to ignite the water heater, just remember that it is part of the fresh water system as well. Then refill the tank to "almost full" and add the bleach. Be sure to do the math first! It's easier when you use a new, clean funnel to pour the bleach directly into the tank through the gravity water fill location on your rig. After the bleach has been added, drive the RV down a bumpy road to mix the contents. Next, using the on-board water pump, pump water throughout the entire system, including the water heater. Once water is running at all the faucets, flush the toilet a time or two. Don't overlook those "out of sight/out of mind" components such as an exterior shower head or faucet, clothes washer connection and ice maker if so equipped. The goal is to get this heavily chlorinated solution into every inch of the fresh water system. Let the solution sit in the pipes and components overnight, then drain the entire system and flush out once again with fresh water. Basically repeat the same process as when you added the bleach. Finally, refill the fresh water tank and the water heater with filtered water. There are many in-line filters available, but I've had tremendous success with the in-line filter from Hydro-Life. It's important to only employ the filter AFTER you've chlorinated the system. Do not allow bleach to enter the filtering device. You're system should now be ready for use. Repeat this process every two tankfuls or so. If you still have odor or taste issues with the fresh water system, it may involve further troubleshooting, but there are many aftermarket additives you can add to the tank to freshen it up also.
Dear Gary, the city water connection on my RV is leaking, so I turned it off. After I disconnect the screws that fasten the cover plate to the outside, does the city water connection cover just pop off, or does it have to be unscrewed or something? I can't see the housing of the inlet by removing the panel in the bathroom and need to find where the leak is originating. Dave Terrt, (Peyton, CO)
Dave, it depends on the type of plumbing line that was used for the fresh water piping system on your coach. If it is rigid copper or plastic, there may not be much "give" in the lines to allow you pull the city water entry out past the sidewall. Flexible tubing used for the fresh water lines is usually more forgiving and can be manipulated somewhat. Still, there has to be a way to get a wrench on the back side of that fitting in order to remove it. Look closely inside the coach; it may be hidden behind a panel or a galley drawer, etc. Once you get it removed, be sure to extend the piping to enable an easier access the next time. If the city water entry is leaking only when the pump is employed, it could simply be a matter of debris stuck in the backflow preventer portion of the city water fill. Before attempting to remove the city water inlet try this: Turn the water pump on, pressurizing the system, and then push a pencil (use the eraser end) into the city water inlet depressing the spring. This will cause water to spray back at you so beware! Do this a couple of times to allow the pump pressure to force out any contaminants that may have been trapped in the check valve. If it still leaks, then remove the inlet. I'm assuming yours looks like one of two pictured here.
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