Page 19 - 2017-Fall Vintage RVing

For additional technical session presentations and papers, go to gmcmi.com/technical-presentations-papers/Observations on How to Obtain Decent Gas MileageJim Kanomata | 1978 Royale | 510-742-110 Applied GMC | appliedgmc.comOn average, we repair six to eight GMC Motorhomes a month. From this experience, along with my 100,000 miles on my own GMC, I have found the following facts. An average GMC Motorhome should obtain 8-10 mpg. If you are getting less, reviewing the following information may be helpful.1. Check the tire pressure with an air gauge. Visual inspection is not precise enough on radial ply tires. Pressure shouldbe 65-75 psi.2. Keep the sewer tanks emptied and carry a minimum amount of fresh water. Fluids add a lot of dead weight.3. Carry only the necessary heavy tools and spare parts.4. You should cut down on engine “warm up” time. Idling the engine causes it to take longer to warm up.5. By reducing your air conditioning usage, you stop the compressor from taking power away from the engine.6. Using synthetic oil will cut down on friction.7. Inspect the mechanical advance within the distributor. The rotor must pivot freely back and forth. Also, check the vacuum advance for movement.8. Make sure the vacuum hose has a positive seal.9. Inspect your air filter. If your filter restricts too much air volume into the engine, then you have to increase the throttle.10. You should drive 55-60 mph and maintain constant speed.11. Ignition wires need to be replaced more frequently on the GMC since the load is considerably more than an average vehicle. Try to obtain a better-than-standardset for greater performance.12. By pulling cooler air from outside the grill, you will produce more power and less throttle is needed.13. Try advancing the timing. Advance it two-three degrees and take a test drive, and make sure it does not pre-ignite. This procedure is called “Power Timing” and is used by Dyno shops to gain more power.14. Pay attention to mufflers with baffles. They can shift, causing extreme restriction to one side. This resultsn an overheated intake manifold, poor power, and poor mileage.FALL 2017GMC MOTORHOMES INTERNATIONAL 19Carbon Monoxide is Dangerous StuffBruce Hislop | 1977 Palm Beach | Ingersoll, Ontario, CanadaCarbon monoxide (CO) is a colorless, odorless, tasteless, but highly toxic gas that is slightly less dense than air. It is formed when burning any carbon based fuel such as gasoline, propane, butane, and even fire wood.Normally, exhaust from an internal combustion engine or a furnaceis expelled into the outside air where it slowly rises and is carried away and dispersed. However, ifCARBON MONOXIDEKnow the Signs!3 Headache 3Dizzinessit enters an enclosed space (likeyour coach), the concentrationlevels will rise quickly without younoticing. CO can enter throughan open window or roof vent witha running generator or nearbycoach, or a crack in the furnaceheat exchanger. Consider yourneighbors and wind directionwhen running a generator or yourcoach. Don’t forget the operation of your oven, stove top, and other fueled appliances, such as on-demand water heaters and space heaters, release their exhaust directly into your coach.When inhaled, the CO molecule basically blocks the blood’s mechanism to absorb oxygen leaving your body organs starved for oxygen. The most common symptoms of carbon monoxide poisoning may resemble other types of poisonings and infections, including symptoms such as headache, dizziness, nausea, breathlessness, and collapse. Neurological signs include confusion, disorientation, visual disturbance, fainting, and seizures.Concentrations as low as 667 parts per million by volume may cause a loss of 50 percent of the blood’s oxygen which may result in seizure, coma, and fatality. An interesting note is that modern automobile exhaust emissions are in the 5-15 parts per million by volume range, while a vehicle without a catalytic converter (like our coaches) range up to 7,000- 35,000 parts per million by volume.CO detectors are readily available, and like smoke detectors, they need batteries replaced regularly. Both also have a life span and should be replaced as per the manufacturer’s recommendation. Note that their life span is shortened in the RV environment (heat, cold, etc.).NOTE: I write this because we believe Paula might have suffered from CO poisoning inadvertently. After a recent rally she was cleaning up in the coach with the windows and door opened. An adjacent coach was started and left idling for about 30 minutes. I came into our coach to find Paula suffering from many of the symptoms listed above. Thankfully Lois Urbanski was still at the campground and came to look at Paula. She had me close the door and windows then turn on the fans and air conditioner to vent the coach. It was two days before Paula was feeling well again.Nausea 3Breathlessness3CollapseLoss of Consciousness