Engine Will Not Start on Natural Gas (Basic Troubleshooting)

1. The first thing to check with Natural Gas is the correct pipe sizing for your application. This will ensure a sufficient volume of natural gas for the engine to run properly. Here is a link to the Natural Gas Pipe Sizing Chart on our website: http://uscarb.com/natural-gas-chart.htm Please take the time to properly understand what is required. This will save you time in the long run! A major issue we see is pipe size consistency, once the pipe size is reduced it cannot be increased. “There is no such thing as a bell increaser, only bell reducers.” {Example having a 3/4" line reducing down to a 1/2" valve then going back up to 3/4" line.} Also if installing a shutoff valve please make sure it is a full bore valve.  
   * Note pressure and volume are not the same. Having the correct amount of pressure is as important as having a system that does not cut down on the needed volume of fuel.
    
2. The load-block adjustment is critical!!! It has to be tested 1 turn at a time in each direction. Typically for Natural Gas it will be 7-9 full turns out. Some engines may take more turns or less turns but 7-9 is a base starting point. Please do not be afraid of tweaking this adjustment to find the “sweet spot” where the engine performs the best.
    
3. If the kit utilizes an adapter, please be sure the adapter is installed in the proper direction. The larger opening of the adapter should be closest to the carburetor. If you are using the snorkel kit take off the hose from the regulator (the hose that goes from the regulator to the snorkel). Try blowing through the hose. You should easily be able to blow through the hose. If not check for blockages in the hose and check that the probe of the snorkel (the part of the snorkel that goes inside of the carburetor) is not kinked or pinched in the throat of the carburetor.
     
4. Only use lighter weight motor oils such as 5w30. This allows the engine to spin faster creating a more powerful spark.
   
   
5. Due to inherent mechanical limitations it is possible to have a generator that out of the box will operate on gasoline and even propane but will not operate on natural gas. Since natural gas requires a stronger spark and proper compression to ignite compared to gasoline and propane.
   
   
6. The engine will have a weaker spark if the Magneto and/or the TCI is rusted. If this is the case these components will require cleaning. 
   * To help compensate for weak systems, setting the spark plug gap to .020" will create a more powerful spark which may ignite the natural gas.
   
   
7. A weak TCI will need to be replaced.
   
   
8. Note: Brand new engines (such as some “Chonda” generators) may have a weak TCI from the factory and may require a better quality replacement. 
   * If the spark plug is not new it should be replaced.
   * If compression is low due to improper valve lash the valves will need to be readjusted.This would be one of the first checks when the engine will not run after many hours of running fine. (Most manufacturers recommend checking this every 100 hours.)
   
   
9. Engines that are affected by any of the above may still function on Natural Gas by first starting the engine on gasoline and then switching over to Natural Gas by using the following method:

• Turn the load-block adjustment all the way clockwise to the closed position.
• Turn on the natural gas.
• (Note: The zero governor will keep Natural Gas from entering into the carburetor.)
• Start the generator on gasoline with No Load.
• Once the engine is up to full RPM’s, turn the gasoline shutoff valve to the off position.
• With the engine now running on gasoline, slowly turn the load-block adjustment counterclockwise (open) until  the engine speed is affected. Now wait for the engine speed to smooth out.
• Continue to turn the load-block adjustment counterclockwise until the engine speed is once again affected.
• Continue doing this until all of the gasoline residuals are completely consumed and the engine is running smoothly on only Natural Gas.
• (Refer to the Master Instructions for the final load adjustment.) 
• After shutdown, count how many turns clockwise it takes to completely close off the load-block adjustment. The next time the generator is restarted, replace step F. with this step and open the load-block to this setting.