Thread Tools Display Modes
Old 03-12-2015, 10:35 AM   #1
New Member
FireScience's Avatar
Join Date: Feb 2015
Location: Indiana UGH!!
Posts: 6
Year: 2002
Coachwork: Thomas
Chassis: Thomas
Engine: Cat; 3126E
Rated Cap: 72 Passenger
Connect a generator to bus fuel tank??

Hi. I just purchased an Onan 3.5kva diesel generator that is built in to its own trailer, for construction sites/rentals I would assume. My goal is to tap the bus's fuel tank so that I only have to worry about one fuel gauge. My question is. First, is this a good idea? Second, the genny has two lines that run to the existing tank. I'm not a diesel mechanic, but can anyone tell me why two separate lines? I got a really good deal on the generator, and I was really looking for something with more power. Any thoughts on whether this will be enough? I haven't done anything with the bus yet. It's still pretty much just a school bus. I was hoping for some A/C and the bus doesn't have factory A/C, so probably going the rooftop route. I'm sure I'll be adding propane along the way at some point. I'm still looking for a very cheap RV that I can rob for bathroom parts. I still haven't decided exactly what we're going to wind up with yet, but for now the bus will be our Uhaul to get us from Indiana to Florida, and then who knows. I was leaning toward going the "party bus" route, but could wind up going full RV conversion. Anyway, I would appreciate any thoughts on the subject(s).
Jeff R.
FireScience is offline   Reply With Quote
Old 03-12-2015, 10:45 AM   #2
Bus Geek
lornaschinske's Avatar
Join Date: Jun 2004
Location: Roswell, NM
Posts: 3,583
Year: 1986
Coachwork: BlueBird
Chassis: 40 ft All American FE
Engine: 8.2LTA Fuel Pincher DD V8
Rated Cap: 89
Don't know why two lines. The POS Onan in the Class C only had one line. I do know the fuel line is held up to where it will not pick up the last 1/4 tank of fuel. Why don't you contact Onan?
This post is my opinion. It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose.
Fulltime since 2006
The goal of life is living in agreement with nature. Zeno (335BC-264BC)
lornaschinske is offline   Reply With Quote
Old 03-12-2015, 12:12 PM   #3
Bus Nut
Join Date: Jul 2011
Location: Winlcok, WA
Posts: 895
One line is the supply line and the second line is the return line.

A car with a gas engine and a carb uses all of the fuel that is sent from the tank to the carb.

A diesel engine uses only a fraction of the fuel that is pumped up to the injection pump. The excess goes back to the tank to be pumped back again to be used.

Using your bus fuel tank is not a bad idea. Just don't plumb the fuel pickup for the genset anywhere below about 1/4-tank.

Running out of fuel for a genset is just an annoyance.

Running the bus fuel tank dry because the genset used up all of the fuel is a major PITA.
cowlitzcoach is offline   Reply With Quote
Old 03-13-2015, 12:40 AM   #4
Bus Nut
Join Date: Oct 2011
Location: Snowflake, Arizona
Posts: 316
Year: 1996
Coachwork: Blue Bird
Chassis: All American Rear Engine
Engine: C-8.3-300 Cummins MD3060
Rated Cap: 40 Prisoners
Another thing to think about on generator fuel is to mount a separate tank on the trailer and label it for off-road diesel fuel which allows you to use the red fuel which
doesn't charge the highway tax which runs at least 30 cents per gallon more than the green colored fuel with the extra road tax applied.
Dragonpop is offline   Reply With Quote
Old 03-16-2015, 09:11 AM   #5
Outcast's Avatar
Join Date: May 2014
Location: North Georgia Mountains
Posts: 104
Year: 96
Coachwork: AmTran
Chassis: International
Engine: DT466
Rated Cap: 75
Personally I would be cautious with the line due to connecting and disconnecting them. Air in a diesel line is a problem so you would need some special fittings to keep the lines primed during disconnect.
Outcast is offline   Reply With Quote
Old 03-16-2015, 09:20 AM   #6
Bus Geek
Join Date: Aug 2011
Location: Stony Plain Alberta Canada
Posts: 2,939
Year: 1992
Coachwork: Bluebird
Chassis: TC2000 FE
Engine: 190hp 5.9 Cummins
Rated Cap: 72
Originally Posted by lornaschinske View Post
Don't know why two lines. The POS Onan in the Class C only had one line. I do know the fuel line is held up to where it will not pick up the last 1/4 tank of fuel. Why don't you contact Onan?
Contact Onan? Lol funny.

Your generator had two lines also. You just did not see the other one.

Like has been mentioned, they all need a feed and a return.

If the generator was mounted on the bus, I like the idea of running it from the buses fuel tank.

On the trailer, I would keep the generator on it's own fuel tank. Not worth the trouble.

"Don't argue with stupid people. They will just drag you down to their level, and beat you up with experience."

Patently waiting for the apocalypses to level the playing field in this physiological game of life commonly known as Civilization
nat_ster is offline   Reply With Quote
Old 03-16-2015, 10:08 AM   #7
Bus Nut
PDBreske's Avatar
Join Date: Sep 2010
Location: Ocala, FL
Posts: 593
Year: 1995
Coachwork: Bookmobile body by Farber
Chassis: International 3800
Engine: Navistar DT466/Alison MT643
Rated Cap: 1
The giant 16KW marine diesel generator that was on my bus when I bought it (former bookmobile) also had a feed and a return line plumbed into the main engine's fuel lines. It's a great idea if you plan to use the genset only occasionally because you'll never have to worry about the fuel supply going bad for lack of use (although this is less of a problem than on a gasoline generator). Also, provided the main tank is near full, you have a practically unlimited source of fuel as most people wouldn't run their generator enough to burn through the entire supply of diesel before their next trip to refuel.

On the downside, as was mentioned, there is the slight chance you could use all of your main engine's fuel, and running the vehicle's engine dry is a bad idea. In my case, the generator's fuel lines were an oily, leaking mess that I was glad to be rid of.
Read about the "Camel" RV Conversion project!

My first passion is photography. Visit my website to see some of my work.
PDBreske is offline   Reply With Quote

bus fuel tank, diesel generator, electrical, fuel system

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 06:47 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2016, vBulletin Solutions, Inc.