Running gas in a Deuce

[Lorax]

OK, gas is listed in the available fuels list, but not recommended compared to diesel. Here's the situation. A department in my home town has a deuce. It's used for official city things. I've seen and heard it running around on occasion, and it sounded normal. Well, apparently it has had some problems starting, so I was asked to take a look at it. Because it's cold and windy outside, I gave it a quick look-see at the batteries and fuel tank.

1. Battery terminals are horribly corroded. A bad terminal connection gave me trouble one time on my deuce, so that could be part of the problem.

2. Car batteries are being used, instead of 6TL type batteries.

3. One battery showed 12.8 volts, the other showed 8 volts. There's a starting problem right there with the low battery voltage.

4. Smelled like gas in the fuel tank.

I asked one of the fellows if they've been putting gas in the tank. He said yeah, because they don't have a key to the diesel pump.

So here's the question. What kind of damage can be caused by extended use of gas without any lubrication additive? I'm assuming the injection pump, but what else? When the dept boss gets back, the recommendation of getting a diesel pump key or at the very least dumping some lubrication additive in the fuel tank will be made.

Lorax

 

[FireFighterHill]

Gasoline isnt the problem its the octane. High octane will resist combustion under pressure. There should be a data plate on the dash that list the HIGHEST acceptable gasoline octane. I think its like 80 probably lower.

Id say you have a couple of options, if the tank is low fill the rest with diesel and maybe some 2 stroke oil. Or drain the tank and the fuel filters and fill and prime with diesel.

 

[Stretch44875]

Tell them it's junk, then offer 500 for it!

I'd say the inj pump could have issues. Don't think anything else would be hurt.

Sounds like a battery issue, throw a couple of good batteries in it and see what happens. Also add some oil to the fuel tank.

Good car batts are fine for a deuce. Its the 5 tons that hate the smaller batts.

Dennis

 

[kipman]

Dennis is correct, 800 cca car batteries work fine, 5 ton needs all the juice to spin fast enough to start.

 

[avengeusa]

gas is fine if you use it when there are no other fuels available

I ran out of fuel once and had nothing but gas available to me, i put 10 gallons in it and drove to get topped off with diesel, I did add a couple quarts of oil for lube


and i regularly use gasoline to thin the wmo i fuel the truck with after i send it through a fuge

 

[Keith_J]

Damage from gas only? If it runs good, there is no damage. The IP is lubed with engine oil, unlike most other Bosch-designed distributor pumps which are lubed with the fuel.

Yes, it can cause starting issues but once properly warmed up, this problem should go away.

 

[Jones]

This might make for some good reading for you and your buddies.

 

[glcaines]

When I was in the Army in 1970-71, we were instructed not to use MOGAS in multifuels unless it was an emergency. We were to use diesel only and if gasoline had to be used to mix it with as much diesel as available. We were not warned about possible damage to the IP, we were warned about damage to the injectors themselves, that the only lubrication the injectors received was from the fuel.

 

[doghead]

They just don't start well on gasoline.

 

[Blood_of_Tyrants]

The octane rating on gasoline is an indication of how well it resists spontaneous combustion, but should run okay. I seem to remember reading that gasoline with a max octane of 85 is allowable in a deuce. The problem is extended running will cause wear in the IP. Pour in some filtered used motor oil in the tank (at least 25% but preferably 50%) and the multifuel will happily run all day.

 

[saddamsnightmare]

December 29th, 2009.

Gents:

I was always under the impression gasoline was a war emergency measure.... On my truck I never run more then 25% gasoline, the rest is either diesel or WMO, but in the winter a little gasoline will keep the diesel from gelling and saves me from having to get the cetane additive. My best guess would be that the worst that has happened is either the injectors or the IP pump might have issues, but if you get the truck cheap enough, those could be addressed. And yes, like Doghead says up above here, my deuce does not like more gas in the fuel then 25% and it will start sluggish sometimes, say 4 revolutions instead of two.

Good luck on the truck,

Have a Happy and Safe New Years,

Cheers,

Kyle F. McGrogan

 

[emr]

It is a multi fuel it will run a long time on gas, blood of tyrants is correct, pour some 2 cycle oil in there and it will lube her right up, its your batts, a bad batt will not let her run, more important pull the plug in the bottom of the tank and see if water comes out or all fuel, and check the filters , draining some start with the first one in front there are 3, and work your way back, An extremly good buddy used to call me years ago and say" these trucks they call deuces are awesome , we have access to use em in the desert and run em till empty fill em up with gas and oh man they are a good 5 miles an hour faster, i have found this to be true, Like it says in the video from uncle sam pour in what U need and go. Your filters having dirt or water is way more important than gas, I would worry about those guys dumping dirty ol cans of gas to get rid of em in the ol army truck , if its clean its fine...Randy

 

[datsunaholic]

I found mine started easier with 5 gallons of free "oops" gasoline mixed in with a half-tank or so of road diesel, and didn't seem to run any different. Oops Gasoline is what you drain from a Diesel Jetta/Passat/Mercedes/etc when the owner forgets which car they're filling up. Can't use the stuff in a normal Gas car (because the Jetta tank wasn't empty when refilled) and can't use it in a regular Diesel, so my buddy who runs an auto repair shop gave me what he drained out of the car. He would have had to pay to dispose of it otherwise.

Of course, I had such a low concentration of Gasoline (20+ gallons diesel to less than 5 gallons gas) it probably didn't make much difference at all.

 

[coyotegray]

Gas is ok as long as you also included some oil to lub the IP. You just get less power. Gas only over a period of time will be hard on the pump and eventually ruin it.. How long have they been running it on gas? Are they using only gas..?

I would first check the filters, etc. At least drain the primary...Then drain the tank, fill it a little with Diesel and purge the fuel system until you get diesel at the injectors and then give it a try..

You can just jump it until you can determine the problem or try jumping it first, that may be the only problem.

Andy..

 

[jollyroger]

If I remember correctly there is a valve in the fuel line somewhere on the side of the engine block. It is supposed to measure the viscosity of the fuel in order to keep the feed to the IP correct for the fuel type. I mention this because some trucks have this part bypassed so that if it fails it does not leak fuel directly into the crankcase. If it is bypassed it is my understanding that damage can be caused to the motor by running anything other than diesel. I am sure the more experienced mutifuel guys can chime in on this. I just remember this discussion in a post from a couple months ago.

 

[coyotegray]

You can still run gas with the density compensator bypassed, the throttle will just not respond the same..

Andy..

 

[stumps]

All the FDC does is measure the thickness (density) of the fuel, and move the throttle stop accordingly. They reasoned that thicker fuels have more heating value, so they won't let you press the pedal down as far with them as they will with thinner lower heating value fuels.

The idea is that the FDC will make the maximum HP about the same regardless of the fuel. Prior to the FDC, they set the Injection Pump to a compromise setting, and the engine would smoke with diesel, and be very weak with gasoline.... That was back in the LDT-427 days. Most of the bad vibrations on gasoline use seem to come from those days (1965'ish).

-Chuck

 

[TexAndy]

All the FDC does is measure the thickness (density) of the fuel, and move the throttle stop accordingly. They reason that thicker fuels have more heating value, so they won't let you press the pedal down as far with them as they will with thinner lower heating value fuels.

The idea is that the FDC will make the maximum HP about the same regardless of the fuel. Prior to the FDC, they set the Injection Pump to a compromise setting, and the engine would smoke with diesel, and be very weak with gasoline.... That was back in the LDT-427 days. Most of the bad vibrations on gasoline use seem to come from those days (1965'ish).

-Chuck

Neat. Good info.

 

[Scarecrow1]

The multi fuel aspect is an emergency option .It is not to say anything other than diesel fuel is ok to use on a regular basis. Prolonged use of gasoline will damage it and yes affect the proformance greatly . Gasoline with Ethanol is even worse than regular gas ... So just go through the drill and let them know what the problem is .....then offer them 500 dollars for it ....

 

[stumps]

It is interesting to look in the table of fuels for the Deuce MF engine, as shown in TM9-2320-361-10 circa 2006:

Table 15 Permissible Fuels:

FUEL
Primary Fuels
​

Diesel Fuel, VV-F-800, grade DF-2
Diesel Fuel, VV-F-800, grade DF-1
Diesel Fuel, VV-F-800, grade DF-A

Alternate I Fuels
​

Turbine fuel, MIL-T-5624. grade JP-5
Distillate fuel, MIL-F-24397, ND
Commercial diesel fuel 2-D and no. 2
Diesel fuel MIL-F-16884
Commercial diesel fuel 1-D and no. 1
Turbine fuel, aviation , grade JP-7
Aviation gasoline, MIL-G-5572, AVGAS 80/87
Commercial aviation gasoline grade 80/70
Commercial gasoline, leaded, low lead or
unleaded, when research octane number is 89 or
below, or octane number displayed on retail
gasoline pumps in CONUS is 85 or below
Commercial aviation turbine fuel, jet A
Commercial aviation turbine fuel, jet A-1
Any mixture of primary and/or alternate I
fuels listed above...

The table indicates that the fuels are listed in order of preference.

The part that is interesting to me is both Diesel 1-D and 2-D are listed with AVGAS 80/87, 80/70, Commercial gasoline, leaded, low lead or unleaded 89. And that they say nothing about deleterious effects from using any fuel in the alternate I block.

You would think if the deuce's nuts would come un-twirled on gasoline that they would have put it in the Alternate-II table.

-Chuck