Gasoline consumption in a Generator

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Old 08-12-20, 10:07 AM
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Gasoline consumption in a Generator

Has anyone ever figured out how long gas will last in a generator? My 5,500 watt B&S, with peak in 7,500 holds 7 gallons of gas. During Sandy, I only ran a few extension cords and it appeared that the gas consumption was not too bad. Today, I have an interlock kit with all the circuits labeled. I figured everything to run (without AC) would be about 3,000 - 4,000 watts, but we are talking having lights in every room (lamp that is), all cable boxes, computers, fans, etc. Recently in NJ, a lot of people lost power, and I was lucky enough to not have any power outages. Even after Sandy, the power has not gone out for more than 4 hours (we have been lucky).

Given that I store about 20 gallons with stabilizer, that is used at least and turned over annually, I am wondering if this is enough. Based on what I am reading, it appears this would only last at most 24-48 hours, but I could be wrong. Gasoline is stored away from the house and in the shed.

Has anyone ever figured out (approximate would be great) how long the gasoline lasted? Please mention the size generator and what you would be running. Because the power has not really been out for over a few hours, I have not been able to do my calculation, etc.

Approximately every other month, I run the generator for 15-30 minutes and it starts right up. Every 2 years, like clock work, I change the oil. Any thoughts? Thank you.
 
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Old 08-12-20, 01:35 PM
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Too many variables really, I would just drain it out, measure a gallon, plug in a decent load that approximates what you will expect, and run it until it stops and time it. Then you know how long run time per gallon. The more load, the shorter the run time. Keep the gas in air tight containers, use non-etjhanol, and store int he darkest coolest place you safely can and it can last a long time.
 
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Old 08-12-20, 01:53 PM
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How long auto gas lasts in storage depends on a lot of factors like heat, how well the container is sealed and what gas you purchased. There is no set time when it goes bad. It's a slow slide from the day it left the refinery. I also find that motion helps in extending the life of fuel.

If you leave gas in a machine and it sits motionless for six months the carburetor may be gummed and varnished so it wont run. But if that same machine is taken out and run for half an hour every month it probably will be OK after six months. I think the vibration and motion keeps the varnish particles in suspension and doesn't let them solidify and clog things.

I would drain the gas from the generator and burn it in your car. After you've drained the fuel run the generator until it sputters. When it stutters play with the choke to keep it running as long as possible to burn as much of the fuel out of the carburetor you can.

Fuel stabilizers can help slow down the formation of varnish and when I had a gas powered boat I would treat it's fuel before putting it away for the winter. The down time usually was about 4 months and I never had carburetor trouble in the spring. The exhaust did stink and the engines didn't seem to develop full power until after the old fuel was used and new added.
 
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Old 08-12-20, 06:37 PM
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I've noticed the same Pilot Dane but my belief is that the reason for that is because the fuel in the carburetor is exposed to air, with the carburetor having a bowl vent and exposure to the atmosphere. That gas in the carb goes bad quickly, but if you crank it up and burn up that in the carb before it goes bad, new gas enters and the process starts over again.
 
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Old 08-12-20, 06:48 PM
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I cant give you any direct, specific answer & I also believe that there are many variables. I haven't tried it, & I have never used mine for the time to run a full tank of fuel, but the info that came with my Predator 4000 said to expect about 8 hrs per tank full. So, 3 tanks a day. TBH, I haven't even tried to pay attention, I fill it as needed & don't really think about it. I'll have to say that I have run it maybe 3 or 4 hrs one time & I wouldn't be surprised if 8 hrs or more per tank was true.... give or take.
 
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Old 08-12-20, 07:25 PM
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During Sandy I used appox 5 gallons a day to run my 5kw Honda. I shut it down from 1-6 AM. It won't run the central air and if I needed heat it it would have run non-stop. My house is all natural gas which is very helpful reducing the load on the generator. During Sandy I didn't have power for 15 days. Spent a lot of time in gas lines. I have four 5 gallon gas cans. I rotate them into the mix for lawn cutting and trimming. At the change of the seasons it all goes into the cars. I use Sea Foam as the stabilizer. I only keep 2-3 gallons in the generator and always run the carb dry.

I have several Honda 5kw generators that are all over 30 years old and have never had a fuel problem.
 
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Old 08-13-20, 03:01 AM
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I am also assuming during a dry run, that a generator will consume gas without any type of load. I think what the next step is to run the gas dry out of the generator, and then do a test run with 1 gallon. This way, I can turn on one lamp in each of the rooms (13 watts), all the cable boxes, televisions, and everything in my office. The freezer and refrigerator in the garage will be on, along with the refrigerator in the kitchen, and 3 small refrigerators upstairs. Phones will be charging, and my office will be up and running, with everything on. This will be interesting to see how long the gallon of gas will last.

Or I can wait until the next power outage and only fill with 1 gallon of gas. It is a good feeling when you start a generator many years later and it still starts. Maybe I will switch to Sea Foam in the future.
 
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Old 08-13-20, 05:00 AM
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Two points. First, I'm in the process of purchasing a generator and have spoken with at least 20 generator owners, none of which run generators overnight. At that pace, 20 gallons should last nearly 4 days.

On gasoline storage, stabilizer helps with some but not all storage issues. It's OK to leave gas in the generator tank but not in the carb or lines. Shut the gas line and run the generator to shut-off after use. Also, gasoline should be stored full in order to minimize oxygen.
 
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