The GMC CCKW

Bad gas smells like turpentine
I got my shop van in finally this Sunday. YEAH! I will post pictures later. I bought the truck from someone who stored it indoors and used it. I ask him if it ran and he said yes. Since I was a little afraid the 18 wheelers might get stuck on delivery I asked him if he would not mind running it before I bought it. The idea was to have a running truck to get it into the shop when and if the 18 wheeler arrived. He said he ran it for about 30 minutes. The truck was stored outside for the last month till I could have it piggy backed back with another vehicle to save money.

The truck arrived Sunday and we smelled the gas tank and it smelled ok…we thought. We put a little primer gas down the carburetor and it started up. We got it to where we wanted it and notice that awful smell of turpentine. I am afraid the bad gas is in the whole of the system now.

What I think he did was add some fresh gas to the tank with some really old gas. I have since found out he had not run it in 6 years.

So here is the question
What is the best way to flush the system? Clean it and put it back right. What problems am I going to encounter? Worse case scenario please so I can plan for it.

If it were mine .I would drain the gas tank ,clean the fuel filter, carefully take the top off of the carb, trying not to tear the gasket if it tears you will have the hassle of locating a new gasket.Clean out the float bowl.Put things back together pour fresh gas in it and run it. You maybe do not have to do the carb. step but is good for your own piece of mind.You may as well change the engine oil while you are at it it probably hasnt been changed in years Hope this helps.

I agree with the cooler king, Clean the filter, carb and lines first. If you don’t want to remove the tank for a quick test, just put a fuel hose between a clean jerrican with new fuel in it...
and the input of the fuel filter ; then run the engine. You will see if the turpentine smell has disappeared. If not (worse case ), you may have a problem with your engine.
To clean the tank, the best is to remove it from the truck and flush it with some dry solvent.

Thierry.

Ok I agree so I drained the tank but I had to use and pump because the gas drainage nut is frozen. I did not want to force it since I plan to take the tank off. I am glad I did because in draining the tank it had a lot of crude in it. It also had twenty plus gallons of turpentine smelling gas. I started taking the tank off but ran into a problem for me. You folks who work on these might not see it so but you have done it before, this is my first .

How do you get the tank off without getting the sending unit connection damaged. I removed the gas line connections but the sending unit wire is connected and I can not get me hand to it. I am afraid if I loosened the bolts and start to remove the tank, I will rip the wire from the connections. The tank has a strap around it and under the tank it rest on a shelf that I do not think will hold it's weight. I know the sending unit and connected wire works at the moment so I am not sure how to proceed. Just what is the best way to remove the tank?

Hi

I assume you are taking out the 8 bolts & nuts that secure the tank assembly to the body?, you should be able to support the tank underneath the stone guard, what you are calling the shelf, to save damage to the sender unit, consider snipping wire inside the chassis, this can be joined again.
I have been trial fitting my shop van tank on & off for some months, supported under stone guard with no problem.
Is your shop van a ST5 or ST6 ?

Regards
Shopnut

Robc,
I have the ST5 as it does not raise up. I assumed earlier that the tray that the gas tank sits on was just that... a tray. However, now that I have consulted the Ord 9 snl G-227 it shows what I thought was a tray is part of the tank assembly and is called a "baffle" in the book. (stone guard) I did not realize bottom piece "baffel-Stone guard" was part of the tank assembly. That makes it easier. I can do as you say and build a box just a tad lower than the tank, undo the bolts and reach under and take the wiring lose. I really hate to cut the wires if I don't have to.

The van I have is an open cab, was redone by the guard in 1951, somehow either before or after would up in France or Holland as it has the French data plates. It was bought by the guy I bought it from in the early 1990's. he played with it for a while, took it to Normandy in 1994 and sometime after that lost interest. It was stored indoors and has not been run since 2002 or 2003.

I intend to clean the tank. Have you been inside your gas tank? The only experience I have with gas tanks is on my WC 15, Dodge Command car. It was constructed in a honey comb fashion. It had so much corrosion I had to have it cut open and recoated just to save it. I really hope the inside of this tank will not be honey combed and easier to clean. Do you know? It will be sunny tomorrow so I think I can get it off.
denny

Does anyone know how long the gas product "Stable" protects gas from breaking down?

It might be worth checking with your local marine engine dealer. The likes of Mercury Engines under the Quicksilver name market a winter fuel product, for preserving fuel in storage tanks of boats. So I guess 6 months or so is its design life.

On the carburetor thing, I had big problems with smooth running when I first had my 352. This was because fuel had dried out in the carb, and the residue, like shellac, blocked some tiny internal air passages. A full carb strip and a 2 -3 day soak in Diesel, followed by an air gun blow off did the trick.

I drained the "turpentine" and got mileage out of it by running it off in my diesel car, at a 10% mix.

Hammerhead wrote:Does anyone know how long the gas product "Stable" protects gas from breaking down?

It says 1 year on the bottle.

I have gone about 9 months but no longer.

I still mix new gas with Stabil gas 50/50 before starting. The only thing I have found is that it prevents varnish from forming in the carb or fuel pump while sitting for all those months saving the labor time of a removal and cleaning. Especially on Lawn Mower/Snow Blower engines.

Stabil Fuel Stabilizer

Check the FAQ's on this page. Some good tips

http://www.goldeagle.com/sta-bil/index.htm

Be carefull when you disconnect the wire from the sending unit.If the stud turns along with the nut you may ruin the unit.The nut is probably rusted on.Pulling the whole sending unit with the wire attached is another option. The cooler king

I was lucky and got the nut off of the sending unit and got the wiring disconnected. The tanks was hard to get off as there had been several "modifications" to the bolting system over the years. I won't say what I had to do to get the tank off but it is off. I found so much crude in the tank and rust that I took it to a place that will coat it and it will be no longer an issue for the life of the truck. I took the sending unit out and it was frozen to the half a tank position. The dash gauge read 1/2 a tank so I am not sure if the sender was still working or not. It has been cleaned and now functions. (moves) I have not tested it to see if the resister works. Th gas tank had two separate fuel lines into it. I don't know if they were designed to both work or not. I have not traced the lines down but I had gas come from both disconnected lines when I disconnected them. That is odd to me as I have never heard of that before on a WWII truck but I know little about CCKWs. I started another post called two fuel lines maybe some f you will take the time to educate me some more.

You guys who are reading this should understand I am learning as I go so please bear with me. My hearts in the right place but I don't have a long background in MV's other that my dodge command car.

What TM manual should I buy that will go into great detail about the functions of it all? and... thank you for your kind remarks, I am learning quit a bit reading your helpful comments.

Correction...poor spelling
"maybe some f you will take the time to educate me some more."
This should read "maybe some of you" I left the "o" out.
Denny