Reserve Factory Fuel Tank '74 MCI

Glennman · July 23, 2019, 10:10:13 PM

I just discovered the factory reserve fuel tank on my bus. I have a couple of questions to ask here about it. How in the world does it receive fuel, as there is only a 1 1/2" pipe coming off the top of the main tank to the top of this other tank (too high for any natural transfer); and, how would fuel ever get back to the main tank? Also, there are no fuel lines going to it (?). I'm thinking of using it for my 13 KW diesel generator instead. How does this so-called reserve tank function? Thanks all...

lostagain · July 24, 2019, 06:26:59 AM

You should write a little signature with what bus you have. That would help us help you. In 1974, an MCI could be a MC5, 7, or 8.

JC

buswarrior · July 24, 2019, 06:31:21 AM

Look underneath the coach...

the lines are attached to the bottoms of the aux and main tank for fuel flow.

The one you see on top is the breather between.

Just add a new fuel pick-up on one of the unused blanks on the top face of the main tank. The body panel is removeable for better access while working, find the two big bolts and it lifts off.

I'd keep the aux tank as is. Better range to get in and out of high fuel tax states and back to cheap fuel?

happy coaching!
buswarrior

Glennman · July 24, 2019, 10:33:56 PM

Sorry... it's a MC8. I'll look for the lines at the bottom, and the extra openings in the main tank. Does the fuel transfer from the main tank to the auxiliary via the lines at the bottom?

buswarrior · July 25, 2019, 09:14:51 AM

Simple gravity.

Fuel level in aux is the same as in main tank.

Fill the main, it goes back there on its own. Invisible to you, all by itself.

Happy coaching!
Buswarrior

Glennman · July 31, 2019, 10:17:58 PM

I have a new 20+ gallon diesel tank for the generator, but thought I could tie into the bus tank(s) instead, and save valuable bay space. However, a friend just advised me that I could use off-road diesel for the generator for less $ per gallon. Hmmm...

chessie4905 · August 01, 2019, 04:05:40 AM

13kw? You may find that finding and filling that small tank with off road diesel could be a pita at times. Also, because it is "off road", some sellers jack the price enough, that there is little savings.

richard5933 · August 01, 2019, 04:31:27 AM

Probably would reduce fuel costs in states with very high road fuel taxes, but even if the extra tax is $0.25/gal you would save only $5 a tank.

As mentioned, you have to weigh convenience and storage space against the costs.

buswarrior · August 01, 2019, 05:11:28 AM

Do the math.

How much fuel would you have to burn in that generator for the savings to be worth the loss of space, the foolishness of finding it, and the exposure to enforcement activity, cuz you were at the "wrong" pump...

My guess is this is completely out of balance for most busnuts. Insignificant.

If you run your generator liike a semi-trailer reefer unit, all day, every day, all month, all year, then you likely will save some dough.

Happy coaching!
Buswarrior

ol713 · August 01, 2019, 11:47:57 AM

Quote from: Glennman on July 24, 2019, 10:33:56 PM
Sorry... it's a MC8. I'll look for the lines at the bottom, and the extra openings in the main tank. Does the fuel transfer from the main tank to the auxiliary via the lines at the bottom?

The lines are covered by a metal protective shield. Check the rubber couplings that connect the hard
lines. If after only 40yrs, they are leaking, then they should be on your "to-do" list. Mine were a
real PITA because I had to learn as I went. Won't have do that again in my life time.

Merle

Glennman · August 01, 2019, 08:34:36 PM

I don't know how much a 13 kw generator uses, nor do I believe I would use it enough to worry about the cost. I'm thinking the extra space in the storage bay is more valuable. Thanks all for the great replies.

Melbo · August 02, 2019, 08:09:10 AM

The times that I have been able to check how much fuel my 13kw generator used -- being able to run the generator a long time and then refuel -- I have used between .3 and .41 gallons per hour. I don't know if this helps or not however it is information I use to plan when I will be parked for a quite a while and no electric connections.

HTH

YMMV

Melbo

chessie4905 · August 02, 2019, 10:09:45 AM

https://www.ablesales.com.au/blog/diesel-generator-fuel-consumption-chart-in-litresdf.html

Keep in mind these figures are in litres. Also the amount of load will have a significant impact. Just run your generator on a full tank till it runs dry and calculate by capacity and number of hours run time. Refill tank to get this as fuel pickup may not be on bottom of tank which will greatly effect fuel consumption/hour. Oh, and know how to bleed engine to restart after running out. 😏 For those with the extra coin, they make fuel consumption meters that measure fuel use and subtract fuel return.