Draining the Gas Again

Rex Smith

Rex Smith

Member
I'm having continuous problems with bad fuel in my 1930 coupe. It seems the Model A carb is more susceptible to it than in any of my other cars. The latest tank fouled the carb in just a few weeks.
Any suggestions for stopping this other than buying clear gas? (Station is too far away)
Also, I'd like to be able to clean the carb myself when this happens. What parts of it need to be cleaned?

BTW, there's no sediment in the sediment bowl, and this tank of gas hasn't even begun to discolor.

thanks, rex
 
I put 1980-ish GM filter in my30 coupe, under the tank . The fittings are flare just like the model A. Does require some plumbing rework


jb
 
Rex it seems very odd that you are having fuel go bad on you so quickly. I think that there is something else going on that is causing problems.
What symptoms are you having to make you think the fuel has gone bad?
 
I repair lawn equipment I tell my customers "if you dont plan to burn it this week don't buy it." Here in eastern ohio 10 days is a long life for pump gas. 6o% of my work is fuel that has gone bad related.
 
Dave. The engine will run for a few seconds and then die. The first time this happened, I changed the fuel and it fixed the problem. The 2nd time it happened, I changed the fuel, had the carb cleaned out and it fixed it. This is the 3rd or 4th time (slow learner?), same symptoms.
I will start using Stabil in the tank, but right now I'd like to know how to clean the carb myself so I don't have to pay someone else to do it.
thanks
 
Possibly rust or crud getting into the carb from the tank. I wouldn't blame the gas. These things will run on just about anything.
 
Rex Smith said:
Dave. The engine will run for a few seconds and then die. The first time this happened, I changed the fuel and it fixed the problem. The 2nd time it happened, I changed the fuel, had the carb cleaned out and it fixed it. This is the 3rd or 4th time (slow learner?), same symptoms.
I will start using Stabil in the tank, but right now I'd like to know how to clean the carb myself so I don't have to pay someone else to do it.
thanks
Click to expand...

Rex, to clean the carb, disconnect the choke rod. With the gas valve off, remove the single large bolt (9/16" wrench) from the bottom of the carb. Be sure not to remove the main drain plug (should be 1/2" wrench, but may not be).

Lower the bottom half of the carb straight down from the upper half that is still on the engine.

Pour the old gas out of the bowl.

Spray carb cleaner into the tips of the 2 main jets you see in the carb half that you are holding. Spray also into the secondary well. Follow that carb cleaner spray with compressed air.

Shake out all the excess carb cleaner.

Give the float valve on the upper carb casting a shot of spray carb cleaner.

Reinstall carb on the car. Go straight up with it on to the idle jet that is sticking down on the carb half still on the engine. Install the bolt. Reconnect the choke rod.

With a bit of practice, you can do all of the above in 5 minutes.

I suspect you have another problem, not bad gas. Check the gas cap vent by just leaving the cap off for a test drive.

Try another known good ignition condenser. Some will fail when they get hot. When it cools down, it works again.

I use Sta-bil (and MMO). My gas lasts a year, no problem, and I do not get the ethanol-free.
 
Jim, I've left the gas cap off. I'll try the condenser. Thanks for the carb cleaning info!
Dave, I would expect to see crud in the sediment bowl. My assumption has been that the ethanol has been gumming up the carb.
 
Rex, while you have the bottom off, set it on the bench and level it with shims of whatever. Fill it with mineral spirits to 5/8" below the upper edge of the bowl and leave it set for a good while. Your symptoms match a carb I had that was leaking fuel at the bottom of the main and cap jet.
 
I have to agree with Bigsnapper43 on the gas going bad quickly and it doesn't have to change colors or turn orange before it's turns bad, and your motor won't start or runs poorly.
 
I found that the change to ethonal fuels in NJ caused a brownish goo to form on the tip of the jets when sitting, I have always turned off the fuel, —- after a few incidents I started running the engine till the last of the fuel was used up, this cured the problem.
The original zenith is easy to clean as told in post 7
 
Rex remove the fuel line at the carburetor and place the end of it in a container and turn on the fuel to check how strong of flow you have.
It's possible you have a pencil filter in the gas tank itself and its getting blocked by crud. Your glass bowl filter wont necessarily show debris in it if the pencil filter is catching it first.
Also make sure the end of the fuel line where it enters the carburetor isn't sticking out too far past the ferrule and is pressing against the fuel screen in the carburetor itself.

Maybe your float is on occasion sticking in the up / closed position not allowing fuel to flow.
If it happens again take a wrench and tap the side of the carburetor to jar it loose.

Does pulling the choke as it dies change anything?

Jim gave excellent advice on how to remove the lower half of the carburetor for cleaning while in the truck. Taking it completely off of the engine only requires taking off the choke rod, throttle rod, fuel line and then the two bolts that attach it to the intake manifold. Then you can open it up on your workbench.

I have run fuel with ethanol for years in my AA truck and have had no fuel related issues.
 
makes no sense unless the station you are going to sells an inferior product.


find another station
 
It's the ethanol. All gas has it unless you're buying clear gas. US typically has 10% ethanol, which we see in Oregon; UK has moved to 20% and it is wreaking havoc with old cars, destroying fittings, etc.
 
I've sprayed all the innards of the carb with cleaner and blasted them with air. I have to say that I didn't see any sign of contamination or crud. I did notice that the float valve was a little sticky so I cleaned that the best I could but not convinced I fixed it. Put it back together; same symptoms. One thing I did notice is that when I start it, it runs for a few seconds. If I try to start it immediately again, it runs for less than a second. If I wait awhile, it runs for a few seconds again. Seems like that might be telling me the float bowl is filling slowly. I have good feed directly from the gas tank.
 
I took the carb out of my '30 pickup and put it in the coupe. Now it runs fine. Apparently the carb has issues although I can't see anything when I open it up, other than the bowl inlet valve seems to hang up a small percentage of the time.
 
Open up the carb and remove the float and then remove the float valve.
To remove the float use a needle nose pliers to pull the brass pin out of the float hinge. After that the float assembly can unscrewed from the carburetor for inspection and cleaning.

There is a tubular screen in the carburetor where the fuel comes in. Remove it and check to be sure it is clean and that the steel fuel line doesn't press against it.
 
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