Running generator on Natural Gas

Learjet has it right. I cut my natural gas engine teeth on a Worthington, NG compressor (Big enough to have a catwalk). Two distributors, and two spark plugs per cylinder.

Don't expect natural gas fueled engines to have as sweet an exhaust odor as an LPG engine.

FYI...

Generator Will Not Start on Natural Gas



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.

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.

* 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.

* A weak TCI will need to be replaced.

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.)

6.) 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:

A.] Turn the load-block adjustment all the way clockwise to the closed position.

B.] Turn on the natural gas.

(Note: The zero governor will keep Natural Gas from entering into the carburetor.)

C.] Start the generator on gasoline with No Load.

D.] Once the engine is up to full RPM’s, turn the gasoline shutoff valve to the off position.

E.] 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.

F.] Continue to turn the load-block adjustment counterclockwise until the engine speed is once again affected.

G.] 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.)

H.] 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.

Hey every one. I got some time recently to experiment with my generator a little more and i wanted to share it with everyone here.

Since I found that my generator was not making enough vacuum, i took of its carburetor and took the Natural gas jet (orifice) out and sealed the hole. Then i drilled another hole in the ventury tube exactly where the vacuum is at its peak and installed the NG jet in there. Finally i ran the generator and vacuum was quite strong than before.

Now the generator is running on NG without choke. But there is still a problem. When loaded and running smoothly the generator surges for a few seconds and then runs smooth again. Then after a while it surges again for a second or two and then runs smooth again. Any idea about what is causing this occasional surging?

Learjet wrote:


What type of regulator do you have?

I do not at this time have a tri-fuel, when I had operated a propane generator it had a demand regulator.

The point is, that you need different settings for NG than Propane. You are not arguing that, you are only picking on my choice of terminology, so there is no point in continuing, since we both agree a engine set up for PROPANE needs to be re-set for NG.

Depending on how the conversion was done, it may require new parts, or it may just need re-adjusting, That I can not tell you since I did not mess up the conversion.

sharp3 wrote:
Okay, I experimented a little with the demand regulator and found that when i slightly push the primer button on the regulator, the generator stops surging and runs smooth.

So this means that either the regulator is not working correctly or the carburetor is not producing enough vacuum to draw in adequate gas, right?

OR the hose from the regulator to the spud tube is too small in diameter to allow sufficient fuel flow.... Thus causing your load block adjustment to be impossible.

YMMV.

aruba5er wrote:
Golden HVac said it all and is 100% right. pressure and btus.

So how does that help the OP?

His statement doesn't explain how to run on both NG and LPG, which my generator has done many times, it seems to indicate something else.

Golden HVac said it all and is 100% right. pressure and btus.

wa8yxm wrote:


An orifice is a small hole from which stuff spews forth..


The problem is.. He's not getting enough of the fuel.

It remains that he has it set up for propane, and he's trying to run it on NG, won't work that way.

Yeah I know what an office is:S I don't think they are used on tri-fuel conversions, and from your comments it sounds like you never actually had one of these portable ones. They are not the same a Generac or Onan type generator. That is what the load block is for, to adjust the mixture for LPG or NG.

What type of regulator do you have?

wa8yxm wrote:

The problem is.. He's not getting enough of the fuel.

It remains that he has it set up for propane, and he's trying to run it on NG, won't work that way.

Well the mechanic insisted it'll work on NG too. Any way what do you suggest I do to make it run on NG?

Learjet wrote:

wa8yxm wrote:
You should have specified NATURAL GAS as your fuel, not LP, the orifice size is quite a bit different.

never seen one with an "orifice", all I've seen and used have a adjustment screw.

An orifice is a small hole from which stuff spews forth..

Some are adjustable, these usually have a screw with a long taper that goes in the hole and partially obstructs it, They are also called Nozzles or jets and are part of every carburetor.

I used the term Orifice because where I have had to convert from Propane to NG, that was the name of the device, but metering jet might have been a better word.

The problem is.. He's not getting enough of the fuel.

It remains that he has it set up for propane, and he's trying to run it on NG, won't work that way.