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Fuel delivery and tuning for propane vs naural gas

CrazyCooter

Registered
The 1" pipe is going to seriously limit gaseous fuel flow. Sounds as if a gaseous-powered generator is not in the cards. Another possibility is a 30-45KW diesel generator with its own sub-base tank. Fuel maintenance would be required, however. zuhnc
I have considered this. I would make sure the generator was rated under 50hp and 37kw or you would have to get an air quality permit. I would just get a mobile unit and take the wheels off of it so it couldn't be stolen easy. You can imagine the demand for generators here right now?

My plumber buddy wants to run 2" to it and see what it will do. Even if I can get 12-15kw out of it and surge 25kw for a few seconds I could still operate the shop. I'm invested this far........Plus it's already set up for the NG! The propane guy thought the NG was the best way to try also.
 

Birken Vogt

Registered
The pipe coming out of the ground is high pressure. The few feet of 3/4 and the few inches of 1" after the regulator is not going to seriously restrict flow. I would go for it if you can get the rest of the run, be it 1.25" or 2" or whatever to calculate out.

Otherwise I have a little diesel unit here for sale. PM if interested.
 

CrazyCooter

Registered
The pipe coming out of the ground is high pressure. The few feet of 3/4 and the few inches of 1" after the regulator is not going to seriously restrict flow. I would go for it if you can get the rest of the run, be it 1.25" or 2" or whatever to calculate out.

Otherwise I have a little diesel unit here for sale. PM if interested.
That's what my plumber buddy told me too. I think it's worth a try.

If this doesn't work out, I'll keep your unit in mind.
 

CrazyCooter

Registered
Still haven't gotten the NG plumbed up....Seems my plumber has just been overclocked chasing down all the work right now.

Power was out this morning, so figured I'd just drag out one of the bigger LPG bottles and at least get the truck on the lift and work with cordless tools. Generator puffed and started right up, but never made it to 1800rpm before dying out. Plugs looked questionable even though there was a weak looking spark, but I only got a couple of puffs and no start.

Inspected the cap/rotor/points. Crack between two cyl contacts. Points looked OK and were functioning open/closed, but just draggged a peice of emery cloth through there. Got all new points, cap, rotor, condenser coming from Napa with just the dist # under the cap, so hoping that will be good.

Replaced the regulator with another I had, but no change.
 

DKamp

Registered
When you get a no-start, the frequent test to 'steer' you between fuel or ignition problem, is to give it a quick shot of something flammable in the intake and see if it takes off.

While it will prove that the engine will start, it doesn't guarantee that the problem isn't ignition or fuel delivery, because gaseousfuel simply requires more ignition (i.e. enough to start and run on gasoline, but not enough to START on propane or NG)... and sometimes a lazy regulator will flow after being primed with something else... but...

BUT...

Natural gas systems frequently experience 'air bubbles'... and sometimes propane delivery plumbing between the valve, regulators, and mixer become depleted of propane. (remember... it's plumbing... it leaks... and that's why there's fuel lockoffs, and valves on tanks)... When this kind of thing happens, it can take some judicious cranking to purge the air... and in the process, a guy like me sometimes draws the conclusion that there's something 'wrong' with something... but it's frequently mistaken for other things...

SO...

Giving it a shot of something flammable will often start it up long enough to get some gaseous demand, clear the air, and start flowing fuel.

Just something I learned (more than once) the 'hard' way... :bonk:
 

CrazyCooter

Registered
Yep, sprayed brake clean into the intake first thing with no change.

I did notice at times while cranking that the engine would hesitate like the timing was too far advanced and that's what led me to look for the crack in the dist cap.

I could smell propane pumping out of the exhaust so that also made me think ignition. Have parts, just have to make time to fix it.

Almost thinking I should just order a new Generac now that I know I'll never get enough gas to run this unit to its potential.
 

DKamp

Registered
Yep, sprayed brake clean into the intake first thing with no change.

I did notice at times while cranking that the engine would hesitate like the timing was too far advanced and that's what led me to look for the crack in the dist cap.

I could smell propane pumping out of the exhaust so that also made me think ignition. Have parts, just have to make time to fix it.

Almost thinking I should just order a new Generac now that I know I'll never get enough gas to run this unit to its potential.
The other situation, is that a gaseous engine CAN become 'flooded'... the mixture must not drive oxygen content below 18%... if it does, it will not be sufficient to support combustion.

I think that if you piped it with fuel to the best possible way, and then TRIED it, you could probably find that your needs could be pared down to be within it's reach. I am certain that you'll find it to be much smoother, more durable, and easier to maintain than anything newer and smaller. According to the fuel demand math, I should not be able to use my generators the way I do, yet they work just fine...
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
Definitely don’t want to replace a high quality Kohler with any modern junk, ESPECIALLY a Genercrap. ;)
 

CrazyCooter

Registered
Definitely don’t want to replace a high quality Kohler with any modern junk, ESPECIALLY a Genercrap. ;)
I agree about the quality difference, but I really don't have time to play with an older unit that I cant depend on at anytime. That little power outrage cost me 6+ hours that I will be making up tomorrow (Saturday).

I need to push a button and go about my business!
 

Birken Vogt

Registered
The Kohler 14 kw has been mostly the same for over 20 years, and we use them at off grid houses all the time, and they just run and run with very few minor repairs. Just have to look after the oil level and change it once in a while.
 

DKamp

Registered
You have two issues- first, is having a robust and maintainable machine that will tolerate difficult circumstances and not strand you for want of immediately-required critical components.

...the second, is having a fuel delivery capacity of sufficient magnitude to provide for the load you expect.

It has been my personal experience that the first issue will not be solved by going to a new Generac.

The second problem will not be solved by picking a different machine, nor a smaller one. A larger generator DOES exhibit a higher base fuel consumption than a small one, but a 35kw generator does not demand it's full fuel consumption at only a 15kw load.

If neither NG nor Propane are feasible, then gasoline or diesel are your next choices. When you have a power outage, the amount of fuel you have ON HAND determines your maximum run time at any given load. IF you cannot buy more fuel, then your critical backup becomes null once that reserve is depleted.

So the best solution for the first, is having a machine that runs well (which I haven't seen anything about yours that sounds disasterous), and the second, is getting a fuel system that will give you as much as it can, for as long as it can, next, assess and prioritize your needs, throttle your usage accordingly, and finally... recover any waste as much as you can, so that you get the greatest return for every fuel dollar you spend... not so much because it cuts the cost of fuel, but because it reduces the amount of fuel wasted on inefficient process and energy exchange. A generator converts chemical energy into heat, which by internal combustion, becomes pressure, which is converted to force, which is converted into rotary motion, which is converted into magnetic circulation, which becomes electricty. Each step costs energy... and the sooner in each process you can make an energy withdrawl, the more effective that fuel burned becomes.

I'm not standing there, I don't think you need as much power, or as much fuel flow, as you think. I do think that the older machine you have, will out last, out perform, and outclass any smaller Generac under real working conditions.
 
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