fuel consumption? 7kw onan

Started by winime, October 25, 2014, 11:42 PM

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Dose anybody know how much fuel a 7kw Onan use's per hour with ac and 12v converter running?

thanks Ron.


I think the ballpark value is about 1/2 gallon an hour.....Gregg has been running his genny all summer maybe he can weigh in with his fuel consumption.

gennys run a low rpm so inherently don't... shouldn't... use much fuel
We call our coach "Charlie Brown"


According to the NHM operators manual, available for free to site members, under full load, 1.3 GPH



Dave is spot on. I have a 6kw 1984 Onan thats been cleaned and rebuilt carb on it. With the same stuff running I get 1 gallon per hour. Hope this helps.


Larger generators can actually use less fuel than a smaller one, depending on load. A 7000 watt generator will probably use less fuel than a 4000 with the same load. I have a 7000 watt generac and have never come close to bogging it down. With the air conditioner, converter, and large battery charger for the race car mine uses about .5 gph. My buddy has a coach similar to mine with a 4000 watt onan running about the same things except maybe a crock pot and he figures his is using around 1 gph. He's changing his 4000 out to a 7000 in a couple months when we get it changed out.   

We had to repair the winding wires where they were supposed to be soldered to the slip rings. It's making power now but he has to get a muffler before we change it out. Busy getting the crops out now so the genny will have to wait.


Figure on around a gallon an hour at full load.

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


I stuck hose in a gas can and ran all day. 12.5 AC, TV, a few LED lights, a short micro run...  .5 gph w/4kw Onan.
Don and Mary
2000 TC1000 Bluebird bus conv.


If he is using a gallon per hour on a 4K generator then he has carburetor issues, it is running way to rich. .5 per hour is the standard for a 4-5K generator. I have three military diesel 5K generators and they all run right on .5 GPH loaded or unloaded. It does not seem to matter if it is diesel or gas.


This is right out of the microlite 4000 manual. Full load=0.71 gph (2.7 l/h.  My generac 7000 manual states .59 1/2 load and .99 full load. So if you were pulling full load amps on a 4000 it could use more fuel than pulling the same amps on a larger generator.


Onan BGE manual= No load-.4 gph
1/2- .6
Full- .8
Don and Mary
2000 TC1000 Bluebird bus conv.


Well, I can't dispute the manual and I do not have a flow meter to check mine so I will have to concede that you are right and I am wrong. I had always heard the Onans were thirsty. Funny part is, the military diesels I have are also Onan engines. Both the 5k and 10k generators use Onan air cooled diesels. NOT what you would want in a camper!!!! Has  printed on the fuel tank, "Hearing protection required within 50 feet". W% :D