How bad is it to run out of gas under load?

Portable standby generator troubleshooting and repair questions. (Gasoline, diesel, propane, natural gas)
Post Reply
deni
New Member
New Member
Posts: 5
Joined: Sat Aug 03, 2019 8:18 pm

In the manual it says to always disconnect load before starting or shutting down, so I'm curious what happens if the gas runs out while the generator is powering the house.
Michtech
Contributor
Contributor
Posts: 39
Joined: Tue Sep 17, 2019 5:48 am

Nothing should happen from the engine shutting down it tells you to remove the load on start up to prevent engine stalling and unvoltage/underspeed alarm once the unit is at the correct rpm/htz it's safe to apply a load
Chris
Site Admin
Site Admin
Posts: 1529
Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI
Contact:

There are a couple of things that 'could' happen, but are unlikely... Running any engine out of fuel will lean the engine out since you're adding more air and less fuel. If this is a common thing, I suppose eventually it could cause premature wear on the engine.

The other thing that was mentioned about removing load is more for making sure that appliances and electronics don't see varying voltage and frequency during the shutdown. If the unit is running rough for several seconds while it's starving for fuel, the output could vary wildly. During the re-start however, you DO need to remove the load to allow the unit to start and stabilize. Trying to start an engine with load connected to it would be like trying to start a stick shift car in gear.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
User avatar
jackH
New Member
New Member
Posts: 1
Joined: Wed Feb 19, 2020 4:51 am

Running out of gas may cause the loss of the coil's magnetism of the generator. This happens because the appliances being powered drain the remaining magnetism of the generator when the load is suddenly stopped. The result is that without a small amount of magnetism in the coils, your portable generator will not restart.
Bassguitarist1985
New Member
New Member
Posts: 11
Joined: Wed Jan 23, 2019 12:37 am

Surge and drops in voltage and speed will make the AVR fail. Its trying like hell to regulate, going full field current and somewhere less than that. Component stress could make them fail. If its a capacitor excited, field will collapse.

Connected equipment...resistive loads wont care much, inductive loads will cry, and SMPS loads may fry.

Best thing, dont do it. :-)
Birken Vogt
Top Contributor
Top Contributor
Posts: 114
Joined: Sun Nov 11, 2018 12:02 am

On the other hand, I have seen loads and loads of failures of a mechanical/gas nature that caused the unit to quit while connected to load, and once the problem was fixed everything functioned normally.
Post Reply