Diesel genset fuel line. Ideas, thoughts and cautions!

grantgoold · February 19, 2007, 01:14:49 PM

I am getting ready to run the fuel line to my 3 cylinder 35 hp oil cooled deutz genset. The genset sits on a slide out (joey bed) on the street side rear bay. I need some thoughts or ideas on the fuel supply. I have read previous posts that suggest a stand alone fuel cell for the genset. I have wondered about using the main bus fuel tank.

I need to know the pros and cons of your experiences. I would love not to install another tank just for the genset. I wonder about problems or concerns you have experienced. Could it be as simple as a T in the fuel line?

Any and all help is greatly appreciated.

Regards,

Grant

niles500 · February 19, 2007, 01:18:35 PM

Seperate fuel line to main tank - keep pickup high enough so as not to run your tank empty - HTH

H3Jim · February 19, 2007, 01:24:05 PM

Niles has it right.

I have mine tapped into the main tank on a separate line. the dip tube is shorter than the dip tube for the bus engine so it cant run the coach out of fuel. Although I have a 235 gal tanks, so I'd have to work at it to run out.

I've heard others say that tapping into the line for the bus engine can starve one or the other, which is not good. When you tap in, you'd also run the risk of losing prime. You really don't want to mess with the fuel supply of the engine that gets you home.

edvanland · February 19, 2007, 02:53:01 PM

Grant
I have a MCI 7 and my diesel gen is also mounted on a Joey bed slide in the middle bay. I taped into the main tank with two lines. The supply line is about 9 inches from the bottom and the return line goes in about 4 inches from the top. My Kubota engine has a return line for excess fuel to be returned to the tank. Make sure you secure your lines well and insulate them where they may rub. Needless to say you will need to have ample room for the fuel lines to extend the length of the slide.
That is how I did it, right or wrong but it works well.
ED
MCI 7

NJT5047 · February 19, 2007, 05:16:41 PM

I also used the main tank. However, you have a huge genset...may want to add another tank if you don't have an aux installed in the front bay.
I used an existing plug at the top of the fuel tank for the pickup. Didn't want to attach anything below the fuel level that could cause a leak.
Drilled the return line into the tank opposite the filler.
How much fuel does your engine use? Fuel use would be the only reason to not use the main tank...as others have stated, I wouldn't use the main engine supply, even though there's plenty of "supply", it adds one more point of failure that would stop you in your tracks if the genset fuel line leaked.
The fuel system in your bus will supply enough fuel for an 8V92, so it ain't gonna starve from the genset. Still, the genset could cause problems with the main engine if you use the engine supply line and the generator fuel line develops a leak.
Cheers, JR

grantgoold · February 19, 2007, 06:14:54 PM

JR, I was looking at the system and wanted to propose the following: I see a small nut on the curb side of the tank. It is above the main fuel pickup. I would look at this site for the feed line. It would run to the back of the bus for genset feed. I would then bring the return line back to the tank and t into the main return line at the actual return site at the tank. I plan on using the genset very little and only when absolutely necessary. I do know that the genset consumes 1.7 gallons per hour at 100% load, 1.2 gallons per hours at 75% load and .9 gallons per hour at 50% load.

It seems like I should be safe with running a second fuel gauge inside the coach and monitor the system from inside to help ensure the tank remains safe.

Your thoughts?

Grant

Ace · February 19, 2007, 07:29:48 PM

One more thing to think about is that in some states you can buy "off road fuel" which is cheaper than "on road fuel" and since it's for the generator... why not?

I opted to use a separate tank. No worries of running out the main tank and less chance of being stranded. You can always check to see how much you have left in for the generator. Just because your gauge might say half full, doesn't mean your generator will run all night. Also you can't figure mileage accurately if they are tied together!

Works for me!

Ace

BUR · February 19, 2007, 08:06:22 PM

Grant
I am still in the building stage of the conversion on my Prevost. When I get to the genset I,m going to install a second tank so I can off- road fuel for the Webasto & Genset. Why pay road tax for that fuel?
But as we all know space is always a problem. Good luck
BUR

H3Jim · February 19, 2007, 10:12:13 PM

I think in Cal the off road stuff is about 20 cents a gallon cheaper, which for the amount of actual fuel used and teh total cost of the fuel, the savings is not worth the hassle to track it separately. Especialy since the off road is dyed, and the dye hangs around for a long time, so you can't really run it in the main tank. (but it would be better than walking)

Ace makes a good point about fuel mileage, that goes for a webasto heating system as well.

Dreamscape · February 20, 2007, 03:57:37 AM

I have an older setup by previous owner. A seperate 30 gallon tank for the genset in the forward bay on our Eagle. I asked the same question several months back and decided to leave it alone. I like the thought of having individual tanks. Also thought of running a line from the main to the genset tank with a pump to top off genset tank from main when needed.
Having a separate gauge with genset start and stop on the dash is what I am going to do when I do my dash.
Happy Trails,

Paul

Dreamscape

JackConrad · February 20, 2007, 05:57:18 AM

Everyone has their own "best way". We installed a separate tank where the old heater core/AC evaporaqtor were in our MC-8. We have a gauge fuel gauge in our generator remote panel inside the bus. This allows us to monitor both generator and engine fuel consumption. I do plan to add a pump to transfer from main tank to generator tank for emerency use. Just "our way", YMMV Jack

TomC · February 20, 2007, 08:27:51 AM

I have a transit that did not have a fuel gauge. When I dropped the fuel tank, I lucked out in that there were two 5 screw round plates already there. One I dropped a fuel tank sender in one and the other I built a pick up and return for the generator. I figure a 140gal tank is big enough. If I know I'm going to sit a few days, just top it off at the closest station to where you'll stop. Can check it just by turning on the ignition. Then you don't waste more space with a separate tank that also has to be filled. Good Luck, TomC

Nick Badame Refrig/ACC · February 20, 2007, 08:57:41 AM

One thing I have noticed...

While traveling on interstates, it's somewhat difficult to find offroad diesel on the same islands as diesel.

Unless you always use the truck islands. [I don't use truck islands because of the diesel slop on the grounds and the pumps]

I always try to use Flying J's RV islands or simmular, because of being able to dump the tanks, fresh water, air, on the same island and they tend

to be very clean. I hate having my shoes all craped up with diesel and have to track in the bus.... "I vote for same tank"

Nick-

NJT5047 · February 20, 2007, 11:27:17 AM

Quote from: grantgoold on February 19, 2007, 06:14:54 PM
JR, I was looking at the system and wanted to propose the following: I see a small nut on the curb side of the tank. It is above the main fuel pickup. I would look at this site for the feed line. It would run to the back of the bus for genset feed. I would then bring the return line back to the tank and t into the main return line at the actual return site at the tank. I plan on using the genset very little and only when absolutely necessary. I do know that the genset consumes 1.7 gallons per hour at 100% load, 1.2 gallons per hours at 75% load and .9 gallons per hour at 50% load. seems like I should be safe with running a second fuel gauge inside the coach and monitor the system from inside to help ensure the tank remains safe.

The plug you describe is probably the same that I used for my pickup. Consider returning gen fuel thru the engine return line at the bulkhead fitting (IMHO) would not cause a problem. It definitely wouldn't be a problem if you only ran the genset when the bus engine is not running. Returning the fuel at the tank return fitting would also work. Is your genset in the rear of the bus? If not, the bulkhead return idea isn't a good one. Unlike the supply fuel line, a return line fault won't kill the engine...it will leak liquid gold however.
Don't really need two fuel guages. You could use the existing dash fuel guage with the genset by using a blocking diode and relay (due to your genset 12V system vs 24V bus chassis), to prevent backing power into the bus from the fuel guage. One fuel guage would work and read any time the genset is operating, or the bus ignition is on.
With the minimal run time you project, fuel use shouldn't be an issue. Running your genset 24/7 could be rather expensive.
An auxilliary fuel tank is space consuming, and should have the filler external to the coach. Could be a good bit of work. Whether non-taxed fuel is a good idea (as well as separate genset fuel tanks) depends on useage. If you don't plan to run the generator much, fuel use becomes a moot point. I fall into that latter group. Don't use it much at all. Only continuous use is on the road for OTR AC.
That sort of use does add up, but not much with my tiny Kubota.
You can always fit an aux tank if you find your use is greater than planned.
Install a shuttle pump and have access for both engine and genset.
Best, JR

Dallas · February 20, 2007, 12:20:41 PM

Quote from: Nick Badame Refrig. Co. on February 20, 2007, 08:57:41 AM
One thing I have noticed...

While traveling on interstates, it's somewhat difficult to find offroad diesel on the same islands as diesel.

Unless you always use the truck islands. [I don't use truck islands because of the diesel slop on the grounds and the pumps]

I always try to use Flying J's RV islands or simmular, because of being able to dump the tanks, fresh water, air, on the same island and they tend

to be very clean. I hate having my shoes all craped up with diesel and have to track in the bus.... "I vote for same tank"

Nick-

Nick,
Anytime you want non-taxed fuel at a truck stop, tell the service person who is helping you.
You'll have to turn the pump off and back on again, but they will separate the 2 kinds of fuel for you with no problem.
I've explained this badly, but it's very easy to do.

Dallas