Tonio

My 1972 LT-1 doesn't run too well...it coughs, sputters, breaks up, terrible off-idle hesitation.....

I rebuilt the carb, tuned it up, put in fresh gas......nothing helped.

Opened up the carb again and found all sorts of brown nastiness. Decided to look inside the tank and siphon out the evidence....

Here's what came out:
I have no idea how this car even fired up! Yikes! I guess it had been sitting a lot longer than I thought before I bought it. Shame on me for not checking this out sooner. Lesson learned.

ntfday

Did you blow out the fuel line as well? My 76 was just as bad.

RMVette

Wow, that was full of crap. I'm guessing that was varnish?

Tonio

After I siphoned out all of the liquid crud, I added 2 gallons of apple cider vinegar into the tank. I did that last night and will let it sit until Sunday. I'll drain out that crud, and once the tank is sparkly clean I'll blow out the fuel line up to the engine bay. Was thinking of cranking over the engine using the fuel pump to purge and circulate fresh gas through the fuel line....before re-installing the carb. Make sense?

Tonio

I think it was emulsified (?) water/ethanol. It's suspended within the gasoline, not stuck to the tank at all.

RMVette

There's one station in our area that has 93 octane non ethanol gas (most others it's 87 or 89) and another that has 110 octane racing fuel so I use a mixture of both. I used to use 100 LL from a small airport where my FIL has his plane but they frowned on me pulling up on the tarmac and filling it up.

At 11:1 my engine likes as much octane as it can get. Plus I only drive to car shows...

ntfday

I had the line unhooked at the fuel pump. I didn't want to contaminate the fuel pump any more than it was.

MelWff

I see you are in Beford, I'm over in Danbury. Have been running 10% Ethanol for decades and never saw that before. Since you have a 72 it is low compression and there is no benefit to running anything higher than 93 octane. You may want to check your gas cap seal and also the gas tank neck seal which is made of cork and falls apart allowing water in and gasoline out.

rvazquez

lowbuck72

When I first got my Vette, 14 years ago, the tank was also full of crap. I removed the pickup and sender, and put simple green and a long piece of chain in it, and did the "shake rattle and roll" dance, and then dumped it out. Did this about a dozen times, till the crap stop coming out. After ditching the pickup screen and reinstalling, I put a clean-able glass filter before the fuel pump and drove it. In the beginning I had to clean the filter every few days, and as time went on, less and less often. Eventually it was no longer an issue.

firstgenaddict

I usually pour some denatured alcohol in the tank if the strainer looks gummy... I run it through by running a slight pressure on the tank... It won't gum, it won't harm rubber, & it dries clean...

I was impressed with how clean my original 71 tank is... the car was driven 12,000 miles between 73 and 86 then accumulated only 5,000 miles from 1986 - 2018.

Tonio

Update: after allowing the apple cider vinegar to sit in the tank a few days, I vacuumed it all out with a wet/dry vacuum. t came out clean as a whistle! Filled it with fresh gas and purged the fuel line by cranking the engine over with the fuel line connected to a container in the engine bay. Once the gas flowed out nice and clean, I installed the cleaned and rebuilt carb, then fired her up. Runs great now! I fine tuned the carb and timing and now she runs as well as it ever did.

I still hate this ethanol crap!

RMVette

74Ken

Ethanol free gas is a MUST for any carburated engine. Cars, lawn mowers, weed whackers, snow blowers, Boat motors, etc.

Keep that stuff for Fuel Injected engines only.

Stev-o

All that crap is unbelievable. Good to hear you got it sorted.

mrvette

Typical suburban 1/4 acre house here, nothing fancy, 2 car garage though.....I use electric lawn/yard gear from chainsaw on down to weed wacker......the only thing gasoline operated is the lawnmower.....well, I cured that too, I pulled off the pull start crap, and got welded on a socket to a cut off 3/8 extension, that I put in my 1/2 inch electric drill.......on top of the crank bolt/flywheel and start the thing the easy way.....

HELL with it, I"m lazy.....on my 3rd mower now in the 20 years I been doing this, I buy them used for about 100 bux.......self propelled, AND I speed up the engine and put large wheelbarrow tires in back so they don't sink into FLORIDA sand....easy maneuver, I RUN behind the mower, get a good work out.....get it the HELL over with.....

74Ken

Speed up the engine?

pigfarmer

Well, yeah. Any gas goes bad after a while - and ethanol or not that's obviously been more than a while.
I've stored E10 up to a year without issue. After that I might SeaFoam it and feed it to the lawnmower, not the 'vette.

caskiguy

You may find this of interest:https://www.dragzine.com/tech-storie...-need-to-know/

v2racing

Ethanol first showed up in gas in South Dakota where I was living in the late 70's, so I've run the stuff for 40 years. There were virtually no fuel injected cars back then. I have had no problems with E10 in cars ever, but yes, if you let it sit for years in the tank, you will have a mess and it does go bad a little quicker than straight gas. Likewise half full tanks and fully vented tanks will have problems quicker.

Take it from someone who has messed with old cars for more years than I like to admit, any gas left sitting too long will go bad and make a mess. I cleaned tanks and carbs from cars and motorcycles I bought that had been sitting for years with straight gas in them. They had the same brown gunk and rust in the systems.

Mike