Gasoline turning into varnish after a few weeks in tank

Raner

Member
Hi All, I got a 1949 H Farmall. The gasoline keeps messing up all my fuel system. It's degrading into varnish in a few weeks, It's also creating a bunch of rust in the gas tank. It happened around 5 months ago, had to clean the tank, overhauled carb, replace fuel shot off assembly and replaced all the fuel lines, I also installed an inline fuel filter. Well today I went to start it to do so mowing. I took some fuel with me, when I opened the fuel cap all I could smell was varnish, It had a real bad black residue on the gas cab inner guts and on the neck of the fuel tank at the top. Needless to say the fuel shot off valve was completely plugged up.
Does anyone have any solutions for this problem. I know it's the ethanol in the gas that is causing the problem. The only thing I can think off that can keep this from happening is some sort of additive. Thanks for any info you can provide...
 
When you say ..clean the tank.. how was this done? If you
did not remove the tank and direct a pressure washer
stream behind the baffle in the tank you came no where
close to getting it clean. Even doing that is really a best
effort.
 
Hi,Red MN...
Yes I removed the tank, pressured washed it, I also used some rust removal products that I found online (On a post on how to remove rust from gas tank) ,then pressured washed it again, when I got done the inside of the tank was very clean. It had no rust at all.
I'm going to have to do it again which is no big deal. The problem is I don't want to be doing this every few weeks I need to find a a solution to the problem. The problem is being cause by the gasoline. I need to find a good stabilizer or additive. If I could find some leaded gas my problem would be solved, but no more leaded fuel is available this days...
 
I've found that if you park them with no gas in the tank or very little the tanks stay clean.
 
Well, if dumping the fuel after I'm done working is the only solution, then I guess it will have to be done...
 
I just put in as much as I need to do the job at hand and carry spare gas can with me so if I run out I have gas to get back to the house
 
I'm in the process of cleaning carburetors and draining my
three tractors, but I expected it as they sat in the barn
since last fall. We had a extremely hot summer and it is the
heat that gets them. Evaporates the lighter ends of the
gasoline plus the ethanol makes for a lot of green coatings on
parts in system.

I never have trouble with my lawn mowers because they are used
a lot during the hot time of the year and sit all winter not
drained. Haven't had carb off any of three since I got them in
2006. Using 10 per cent ethanol in the two riders but do use
91 octane no ethanol in the walk behind.

Worst thing I ever did was treat one of the tractors with sea
foam before I shut it down for the year. It plugged the outlet
of the tank and everything in the carburetor and all screens
between.

Sea foam works good if you are using the machine on a regular
basis that is not running quite right, but have seen it really
mess up more than my tractor when it sat in storage along side
of other tractors that were not treated.

I am putting in non ethanol now in the tractors.

When I store my walk behind snow blower for the summer I drain
the tank ( can't get it all) and then dump in some engine oil.
Run engine until it is getting oil mix in carb, turn gas off
and run carb dry.

Makes it a little hard to start first fire up in fall but never
varnishes the carb or tank.

Problem is nothing new as I fought many carb fuel problems back
in the late 50's and 60's but it is worst now than it was. One
tractor that came in the shop looked like you poured tar in the
manifold just from old rotten gasoline. Gasoline had to get
really old then or be exposed to direct hot sunlight weather
back then.
 
"I am putting in non ethanol now in the tractors"
Hi Pete, I live is South Texas, It gets pretty hot down here in the summer months. I'm going to see if I find some Non Ethanol gasoline in the area. I have never had a problem with fuel in the tractor before. But in the last few months it has become a real problem. Seems the older I get the crappier the gasoline gets.
Thanks for the comeback Pete...
 
Did the product you used to remove the rust seem acidic? May be that the surface in the tank was to bare and it rusted because of that? Maybe using a liner type product would solve your problem. But first, do you have non-oxygenated gas available around you? I would try that. Maybe if you have time set the tank with one front corner down in the area your tractor is stored with a quart of non-ox gas in it. Then see if there are any ill effects from it after a couple weeks.
 
Pete Posted "I'm in the process of cleaning carburetors and draining my three tractors, but I expected it as they sat in the barn since last fall. We had a extremely hot summer and it is the heat that gets them. Evaporates the lighter ends of the gasoline plus the ethanol makes for a lot of green coatings on parts in system." This seems to be the problem I'm facing. Thanks for the comeback Red MN...
P/S I use Lucas fuel stabilizer on my 1996 Dodge Ram 2500 Diesel. The Lucas stabilizer is for both Diesel and gasoline so I'm going to add some to the tractor ounce I get all the fuel system cleaned up and I'm really going to hunt for O% ethanol gasoline.
 
YEp the gas is JUNK , and this year for some reason it is more junkier then last years gas. I had to clean the carb on the stinking lawn mower AGAIN for the third time this summer and every week the mower get a fresh tank of gas and every third week the ga can is refilled with fresh gas . Even the car has been running pourly as we have not been driving much and only getting gas about once every two weeks .
 
Where is the gas coming from? If you are getting it from one gas station, go somewhere else, preferably a different brand entirely.

If it's coming from a bulk tank on the farm that hasn't been replenished in a while, the gas in that tank is turning. Stop using it.
 
Here in Arizona, it gets plenty hot. And I have little difficulty with the gas turning to gunk unless it sits for a couple of years. We don't have the humidity like south Texas. It's been 30 years since I lived near Houston and I am sure gas formulations have changed since then.
My 2 cents:
1. change where you buy your gas
2. buy non-ethanol gas if you can find it (look on the internet - we have a website here in AZ showing all the places that sell leaded fuel.)
3. Use stabil in your tractor tank year round.
I have a couple of vintage motorcycles that don't get ridden often. The Stabil product seems to work pretty well. I sold my tractor collection (all 14 of them) two years ago due to health reasons. Used stabil in all of them and never had a problem. And, I used the local 10% ethanol blend.
 
I too recommend Stabil. have used in my tractor that sits inside about 11 months a year with gas and stabil in it. Starts and runs when needed. I have 2 five gallon containers, split the bottle of Stabil between the two and go. Use the Stabil year around in tillers and mowers and generator with no problem.
 
For equipment that doesnt get ran very often, I go to the local small town airport and buy aviation gas. It is 100 octane and is guaranteed not to go bad
for 10 years. Its a little expensive around $5.25 a gallon. But when you can let something set a year and it starts like you ran it yesterday its worth it!
Also you may have not got your gas tank clean behind the baffle.
 
Thanks everyone for all the input on my post...
I will try the additive that you all mentioned and we have an airport here in Corpus Christi and there is a small airport in Alice I go right by it when I go to the ranch (I'll see if I can buy some fuel at one of them). I also found a place that sells O% ethanol gasoline. I'm glad I thought of posting here, Now I got some options and believe me I'm going to give everything mentioned here a try. I will tell you all, the one thing that is going to happen for sure is that NO MORE ETHANOL GASOLINE IS GOING IN THAT OLD TRACTOR'S GAS TANK, Even if I have to pay 10 bucks a gallon for decent fuel and a good stabilizer. I'm getting to old to be repeating the same work over and over again (Cleaning that gas tank is a big pain in the behind) LOL...
Again Thanks each and everyone of you for helping me out...
 
Definitely get fuel that is alcohol free!!!!! I have worked on small engines for 53 years and the past 10 years 90% of our work is fuel and water from the alcohol pulling in water out of the air. Plus it deteriorates in 30 days. A Kawaskai rep told us 15 years ago milk and fuel are both organic. They deteriorate at the same rate. Most fuel we buy today is between 30 and 60 days old. So now we buy it and let it sit for 30 days and it is 90 days old. His question that day was how many of us would drink 90 day old milk??? I have used a product called Fresh Start since 1990 from Briggs and Stratton and not once did I have a fuel problem in anything I used it in and that included my IH 300. But in the past 1 1/2 years, Briggs filed bankruptcy and was bought out. In the process Fresh Start has been removed for cost cutting reasons. The 10 years I worked on outboards we had nothing but problems with Sta-bil. We saw LOTS of problems with it in the lawn mowers and snow blowers. I am not very fond of Sta-Bil. If I was going to use a product today since Fresh Start has been removed I would use Star Tron Enzyme Fuel Treatment. Toro has a product now that looks and smells just like Fresh Start which is what I am going to start using in everything I own. But I also buy only alcohol free fuel and that is the single biggest item to do to help with fuel problems!!
 
We can get no Ethanol gasoline here so it is not an issue for me. Even so Ethanol can be removed from gasoline easy enough if you have a decanter. Add clean water to the gasoline in the decanter and give it a good mix. Let it set for a while and the water with the Ethanol dissolved in the water will settle to the bottom. Decant off the gasoline and it will work just fine. Some guy had a Utube showing just how to do it.
 
We use E-10 in all of our 4 stroke engines with no problems, with no additives, so I wouldn't be so quick to blame the fuel. In our Farmall C
I put a quart of diesel in every 5 gallons of gas, hoping it will reduce rust in the tank, and it runs fine. Old tractors were designed to
run on low octane fuel, they don't need 92 0ctane premium! Taryls fuel test has proven that most additives are just snake oil!
 
Like I said, ethanol is not a problem in a engine that is used frequently. Have to use it in cars and trucks. Problem is in seasonal use where the non use occurs in hot weather.

It can sit all winter here in my mowers, no problem. But in stored vehicles with vented tanks, hot weather and you go green and black.

Same with all gasoline except for the green crap. Been around dead gasoline since a teenager on the farm in early fifties. Turned 85 today and still working with dead gas. . Have one H Farmall to finish right now.
 
You must have a bad problem somewhere as we have been using the 10% for 40
pluss yrs here tractors never have any problems set all .winter and start in
the spring the tractors are As,Bs and Cubs
 
For equipment that doesnt get ran very often, I go to the local small town airport and buy aviation gas. It is 100 octane and is guaranteed not to go bad
for 10 years. Its a little expensive around $5.25 a gallon. But when you can let something set a year and it starts like you ran it yesterday its worth it!
Also you may have not got your gas tank clean behind the baffle.
 
(quoted from post at 07:04:40 09/11/21) You must have a bad problem somewhere as we have been using the 10% for 40
pluss yrs here tractors never have any problems set all .winter and start in
the spring the tractors are As,Bs and Cubs

Exactly!! Same here. NEVER had a problem.
 
The additives do absolutely NOTHING. Taryl Fixes All on Youtube did an 18 month test on 8 different additives and the only one that worked was the "Tru Fuel" which isn't an additive at all but that $20 a gallon gasoline you buy in the metal cans at Walmart and Tractor Supply.

ALL the rest failed, pretty much all at the same time, with the same problem. They did not outlast the untreated pump gasoline at all.

I'm sorry but your problem has nothing to do with ethanol. It has its own problems but one of them is not the gas turning to varnish within a week or whatever. Your main problem is the source of your gasoline. Get it from a different gas station and your problem will go away.
 
You can believe what you want but I have seen the results for 53 years. We had all kinds of problems with the alcohol fuels until we started using Fresh Start. Plus hundreds of our customers who quit using alcohol fuel in their mowers stopped having problems. So you believe what you want and I will keep using my alcohol free fuel and continue to have no fuel problems. There are TOO many bulletins out there by all the small engine companies saying the EXACT same thing.
 
(quoted from post at 18:46:21 09/11/21) You can believe what you want but I have seen the results for 53 years. We had all kinds of problems with the alcohol fuels until we started using Fresh Start. Plus hundreds of our customers who quit using alcohol fuel in their mowers stopped having problems. So you believe what you want and I will keep using my alcohol free fuel and continue to have no fuel problems. There are TOO many bulletins out there by all the small engine companies saying the EXACT same thing.

Yes! I have read some of those bulletins, ignored them and used E-10 anyhow. NEVER had any problems.

You guys that are having problems REALLY need to buy your fuel from a different supplier.
 
(quoted from post at 18:46:21 09/11/21) You can believe what you want but I have seen the results for 53 years. We had all kinds of problems with the alcohol fuels until we started using Fresh Start. Plus hundreds of our customers who quit using alcohol fuel in their mowers stopped having problems. So you believe what you want and I will keep using my alcohol free fuel and continue to have no fuel problems. There are TOO many bulletins out there by all the small engine companies saying the EXACT same thing.

Yes, because it is a convenient scapegoat. The real problem is not good for business: Neglect and lack of maintenance. You start pointing the finger at the customer, and they stop coming back to you.

You know why switching to non-ethanol fuel works so well? It's because folks go out and start their machines periodically just to prove that the non-ethanol fuel made the difference. They put ethanol gas in and leave it sit for months or years. Well, anything is going to have problems if you leave it sit months or years regardless of the fuel you use. Take it to get it fixed, mechanic says it's the ethanol. Well heck, now they're going to go out every week or two and try starting it just to see.
 
Well, I was having serious problems a few years ago with water in my tank. I was getting about a couple of inches out every week in my 200 tank. Lots of ppl here were sure someone was playing with me adding water and stealing gas. Nope. VA humidity was gone nuts. Got gas from diff vendors, same deal lots of water. Not fun having to remove spark plugs, carb bottom, etc to get tractor running again. So I switched to non ethenol gas. Problem solved. Now I will still run 10% if I'll use it in a month.

So, go with your gut. Every location is different.
 
(quoted from post at 16:26:21 09/12/21) Well, I was having serious problems a few years ago with water in my tank. I was getting about a couple of inches out every week in my 200 tank. Lots of ppl here were sure someone was playing with me adding water and stealing gas. Nope. VA humidity was gone nuts. Got gas from diff vendors, same deal lots of water. Not fun having to remove spark plugs, carb bottom, etc to get tractor running again. So I switched to non ethenol gas. Problem solved. Now I will still run 10% if I'll use it in a month.

So, go with your gut. Every location is different.

Lucid,

I don't know how much water "a couple of inches of water" is however, it sounds like much more water than can be blamed on ethanol. Consider the following: At 60 degrees F, 1 gallon of E-10 can dissolve approximately 3.8 teaspoons of water before phase separation begins. This means one could pour 1 cup of water into 13 gallons of dry E-10 and phase separation will not occur. Also consider that once phase separation occurs the ethanol is becomes bonded with the water at the bottom of the tank. At this point the E-10 acts like gasoline in regard humidity.

If you have significantly more water than 1 cup per 13 gallons of fuel I would suspect some supplier is watering the fuel. One of gas stations in our nearby town was caught twice for adding water to E-10. There are also equipment issues that can allow water in the gasoline. My first job out of college was at an oil refinery. A water drain in the storage tank became plugged and water along with gasoline was pumped out of the tank and delivered. Basically all the gas stations in the local town were pumping watered gas into cars. The refinery paid for towing and repairs to anyone who was affected. This was many years ago and before ethanol.
 
I believe the climate the engine is in has more to do with the water problem than any of it. Now as for the rest of it the enthanl is all BS. I buy gas once to twice per year in a 200gallon tank and only use that in our 53 H with no problems and have been using that tank for better than 50 years. I just ran that tractor on the Mackinaw bridge drive with no problems and have been for 13 years. The transmission top is shiny from use as well as the pedals. Yup it gets used regularly and fueld with the same gas over the 6 months to a year in the same tank.
 
Here's what I recently learned about water in my fuel tanks. I, too, started believing that ethanol alone was responsible for a couple of my tractors constantly accumulating water in the fuel tanks. I have
several tractors, all sit outside, 2 of them were my biggest problem. Tried Heet, changing fuel caps, drained the fuel a couple times, covered the tanks. On my 656 gas, I finally pulled the hoods and found
the gas tank sending unit had a bad gasket and allowed water to run straight into the tank. Easy fix. My 450 gas, same problem. I couldn't find any obvious holes so I pressurized the tank (after draining)
and did the soapy water test. This tank had the brazing at the filler neck cracked which would permit water to slowly run in. A little JB weld and some IH red paint took care of it.

Point is, I got stuck hard on the ethanol thing when it is truly a non-issue for me and my tractors and mowers. I also collect old saws and do tend to use ethanol free fuel here. Lot of fuel system parts can
be hard to find and these saws sit most of the time. Best to run them dry if you aren't using them semi-regularly.

Chris B.
 
I thought I had pin holes too, or busted seam. But haven't had any water in tank since.

Very interesting about amount of water that dissolves in ethenol. I would have thought it'd absorb more.
 

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