Got Shell 93 Octane and now barely idles 1973 Dart 340

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Any worthwhile to get a siphon pump and a couple of 5 gallon gas cans?
 
I cramped all the vacuum lines: brake booster to intake. Intake to vacuum amplifer, vacuum advance to the distributer, lines to the charcoal canister. choke vacuum line. No change in idle, except if I use my hand to cover the choke, then idle speed goes up, but it does not smooth the idle out. Exhaust is still abnormal with speed increase.

Thanks,
Eric
 
IMHO from you symptoms above, and the original symptom of barely running:
- Vacuum leak
- Plugged fuel delivery, possibly due to trash in the new fuel (sometimes happens right after a fresh load of uel to the station stirs up crud in the underground tanks): take off the fuel filter and see if you can easily blow through it in the normal direction; be careful to not ingest any fuel

Yes, I would be getting the old fuel out but it there is trash in the tank now, it has to bee pulled to get it out
 
Frozen heat riser and/or muffler clogged as other symptoms since the first sign of the issue was also a different exhaust tone, then carb back fire and rough idle after getting gas?
 
The way you describe this, the engine is getting too much air, and/or not enough gas. Water in the gas accumulates in the bottom of the wells, and since that's where your idle pick-ups are, water passing through the idle circuit, at idle, will produce an instant stall. Of course the mixture screws will do nothing cuz more water or less water is not gonna solve it.
-So I'm gonna guess, the gas you got has oxygen attached to it. See, too much air/ not enough gas. Ima thinking you got a load of oxygenated gas.And screwing the idle mixture screws all in produced the stall cuz that circuit is working perfectly. Screwing them out produced no change, cuz they are at their limit of enrichment, internally.
-This happened to me once, Exact same symptoms. Since I was on a roadtrip I simply upsized the mains and cruised it all out. Next fill up I reinstalled the previous jets, and everything went back to normal..
-Pump it out, problem solved.
-I would go back to that station, and read the fine print, on the bowser.You may find the words "may contain up to 7 million percent alcohol." Or maybe a little less %! lol
 
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AJ/FormS said:
The way you describe this, the engine is getting too much air, or not enough gas. water in the gas accumulates in the bottom of the wells, and since that's where your idle pick-ups are, water passing through the idle circuit, at idle, will produce an instant stall. Of course the mixture screws will do nothing cuz more water less water is not gonna solve it.
So I'm gonna guess, the gas has oxygen attached to it. See, too much air/ not enough gas. Ima thinking you got a load of oxygenated gas
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Gotcha makes sense. I just hate having to deal with something that was not my cause and I will have to pay someone to fix on my dime.
 
TRWRacing said:
Gotcha makes sense. I just hate having to deal with something that was not my cause and I will have to pay someone to fix on my dime.
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Would that be the reason why it seem to run better briefly when I sprayed carb cleaner down the throttle while it was running yesterday?
 
Any oxygen you subtract and or any combustible solvent you might add, will make it run better.
Here's your proof;
Take the carb off dump that junk out. Put it back on, fill it up through the vent stack with fresh known to be proper gas.Since it's an AFB IDK how much the float bowls normally hold, so try 3 to 4 oz to start. Pinch off the supply line to prevent any more of that junk coming in. Have a 10 oz or so mustard bottle handy, half-filled with that same good gas. Dribble a half a teaspoon of it into the two carb bores.
Have the fire extinguisher handy.
Annnnd hit it. If the engine likes it, dribble a lil more gas into the vent stack, until it runs normally. If she doesn't like it, wait til she idles the bowls a lil emptier.
If there is no difference whatsoever, well, color me red, I'm stumped
Wait here's an even easier test;
Leave everything be. Start her up. As soon as she's running, pinch off the supply line. Then dribble a lil of the good stuff down the primaries.Easy does it. If she smooths out, that's your proof. When the idle speed starts dropping that would be a sign that the bowls are running dry, so pour some good stuff into the bowls through the vent stack, until the rpm returns.
If this works, you got no choice but to suck the junk outta the tank.
You did keep the fire extinguisher handy,right?
 
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I tried a siphon pump but its goes about 3 feet and hits a restriction and no fuel. Possibly a screen where the filler tube mates with the tank? I changed the fuel filter and added the bottle of HEET. I will try it on Sat. morning. The old fuel filter no restriction and looked fairly new.

I have a new adapter and gasket for a square bore (Carter AFB) to Spread bore (Thermoquad stock original) intake. If I am unsuccessful then I will have my friend who owns the show that rebuilt the front end take a look.

I will probably pick up a cap rotor as well. I already have a set of NGK spark plugs to replace the Champions, because I don't know when they were done, but the 2 that I look at in each bank looked good with square electrodes and no fouling, no carbon).

Thanks for everyone replies.
Frustating. I have only put 250 miles on it since I bought it.
Eric
 
nm9stheham said:
IMHO from you symptoms above, and the original symptom of barely running:
- Vacuum leak
- Plugged fuel delivery, possibly due to trash in the new fuel (sometimes happens right after a fresh load of uel to the station stirs up crud in the underground tanks): take off the fuel filter and see if you can easily blow through it in the normal direction; be careful to not ingest any fuel

Yes, I would be getting the old fuel out but it there is trash in the tank now, it has to bee pulled to get it out
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Fuel filter looked good unobstructed and I was able to blow threw it. The gas had a slight yellow tint to it.
 
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With E10/15;
The Yellow means the gas is going skunky. It is the first stage on it's way, It will still work in your EFI car, and most small engines.From Yellow it goes to Orange and finally to Red.Of course along the way it goes through various shades of each. In open air, Red can come in less than 2 weeks, Orange in 9 days, Yellow in 5. Sunlight and heat will hasten the color-change. Some modern vehicles will start to pull timing on Dark Yellow to Orange. Red is junk, but can be used for fire-starter
No experience with higher ratio oxygenateds.
Haven't seen Non-oxyginates since 1999.
Fresh E10/15 is clear, almost no color whatsoever, just like it's fresh base fuel.
 
I have some gas in the garage that has started to get a orange tint to it and that gas had stabil added to it 8 weeks ago. How is one to combat this? Pure gas in my area is like 3 hrs away.

I have looked at Edelbrock 1406 Carbs and they saw they are ethanol compatible. I will look at the initial possibly vacuum leak and resolve that, but if bad gas or ethanol related it will probably happen again. What do others do? Ethanol is all political and does nothing to benefit the environment. It benefits the farmers that grow corn in the Midwest, but is terrible for vintage cars.
 
TRWRacing said:
Fuel filter looked good unobstructed and I was able to blow threw it. The gas had a slight yellow tint to it.
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OK, good on the filter. The pickup sock in the tank could be plugged as well as the trash filters in the carb inlets if it has them. The obstruction in the tank maybe a splitter in the lower end of the tube. Try a smaller hose and twist it around some.

If the yellow gas was a piss yellow tint, then I'd agree on the 'going skunky'. Other yellow tints may be OK. If going bad, it would also have a distinct acrid odor to it beyond the normal gas smell.

BTW we run Shell 93 all the time in my son's 340.... runs great, and better than the local ethanol free fuels. It might be formulated a bit differently in Chitown in the summer (read here: Why Gas Is So Expensive During the Summer (And Especially in Chicago)) But I doubt that is the problem in this case; the change in running characteristics in the car were too great, unless it is was water or trash in the fuel.
 
nm9stheham said:
OK, good on the filter. The pickup sock in the tank could be plugged as well as the trash filters in the carb inlets if it has them. The obstruction in the tank maybe a splitter in the lower end of the tube. Try a smaller hose and twist it around some.

If the yellow gas was a piss yellow tint, then I'd agree on the 'going skunky'. Other yellow tints may be OK. If going bad, it would also have a distinct acrid odor to it beyond the normal gas smell.

BTW we run Shell 93 all the time in my son's 340.... runs great.
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It's not quite piss yellow just a real watered down Mello Yello color, but I thought it smelled different not like traditional gas.

The tube was about the size of an index finger. I tried about 6 times moving turning around as I feed it. I will try a smaller tube tonight.

I am not saying Shell is bad. I have always used them. Either a vacuum leak, carb issue or bad gas is my initial assumption.
 
If you see a tanker dumping 5000 gallons of fuel into the station tanks through a four inch line, go elsewhere. You'll be glad you did. The only way to know is ask them when they last had a fuel dump. Someone might know. The pumps are supposed to have filters but who knows.
 
TRWRacing said:
I have some gas in the garage that has started to get a orange tint to it and that gas had stabil added to it 8 weeks ago. How is one to combat this? Pure gas in my area is like 3 hrs away.

I have looked at Edelbrock 1406 Carbs and they saw they are ethanol compatible. I will look at the initial possibly vacuum leak and resolve that, but if bad gas or ethanol related it will probably happen again. What do others do? Ethanol is all political and does nothing to benefit the environment. It benefits the farmers that grow corn in the Midwest, but is terrible for vintage cars.
Click to expand...

TRWRacing said:
It's not quite piss yellow just a real watered down Mello Yello color, but I thought it smelled different not like traditional gas.

The tube was about the size of an index finger. I tried about 6 times moving turning around as I feed it. I will try a smaller tube tonight.

I am not saying Shell is bad. I have always used them. Either a vacuum leak, carb issue or bad gas is my initial assumption.
Click to expand...

We got E10 in 1999,and the community had no options at the time. It was 87E10 or 89/91 with up to 5% alcohol. So we have been forced to adapt.
I have found that E10 will hold it's color for months when stabilized at time of purchase, stored in a closed container, in a cool dark place.
I make good power on 87E10, absolutely no complaints.
You have to consider that E10 is up to 10%, and of that 10% you need about double of the alcohol to make the same WOT power,as you would with straight gas. And streeters run WOT very seldom.
At Idle and low speed the transfers and Mixture screws can easily overcome the slight leaness that might occur. And Part Throttle is no biggie,either cuz you just step on the pedal a tiny bit deeper.Or bring in the PV a tiny bit earlier.And most performance carbs are fat on the idle circuit anyway.
I just don't know what all the hullabaloo is over 10% or 15% alcohol, from the consumption standpoint. Mind you, my S is just a SBM, and relatively tame.
As a Honda powersports tech,tho, I gotta tell you I drilled out a lot of idle circuits. Those Hondas, here at 900ft or so, could feel the E10 right away. And don't get me started on weedwhackers!
 
[QUOTE="But I doubt that is the problem in this case; the change in running characteristics in the car were too great, unless it is was water or trash in the fuel.[/QUOTE]

That's what I am thinking that it was just a coincidence. Most likely a vacuum leak since it looks all goofy with the multiple gaskets, RTV and the adapter or an issue with the carb itself

image.jpeg
 
Yeah.... that is not looking too spiffy! Maybe put a vacuum gauge on a see? Of course, it will vary considerably with cam and idle speed....
 
Pull the carb and adapter off and show us some pics.... serious vacuum leak! I bet you got on it and let off real hard when this happened right?
 
mguner said:
Pull the carb and adapter off and show us some pics.... serious vacuum leak!
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Will do. I got a new adapter today and I plan to work on it tomorrow morning. Of course, Chicago decided to get it's first 90+ weekend and it's hot in the garage now.
 
TRWRacing said:
Will do. I got a new adapter today and I plan to work on it tomorrow morning. Of course, Chicago decided to get it's first 90+ weekend and it's hot in the garage now.
Click to expand...
Gonna feel like a swamp up there!
 
image.jpeg
View attachment 1714942326 I was able to siphon out 8 gallons. Gas gauge says 1/8 in the on position. I will get 2-4 gallons of fresh fuel from another station tomorrow and install the new adapter.
 
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