Ethanol varnish residue: Carb vs EFI

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

BlazerBill

Full Access Member
Joined
Mar 24, 2023
Posts
103
Reaction score
83
Location
Texas
First Name
Billy
Truck Year
1983
Truck Model
Chevy K5 Blazer
Engine Size
350
I’m always struggling with carb jets getting clogged with ethanol fuel residue whether it be on my carb C10 or my pressure washer, etc after they have been sitting for a matter of weeks. Just a month ago, I cleaned the jet in my pressure washer and had to do it again yesterday. The jet was completely plugged. Was wondering if EFI/TBI system jets also get clogged. What’s a good solution to prevent this? Does fuel stabilizers reduce the build up of ethanol residue?
 

nvrenuf

Full Access Member
Joined
Jul 30, 2010
Posts
1,956
Reaction score
2,456
Location
Mobile, Al.
First Name
John
Truck Year
1991
Truck Model
K5
Engine Size
454
I put Stabil in the tank of my Blazer, the carb seems to be doing ok even though it sits quite a bit.
For small engine stuff I try to use ethanol free gas and if it's something I don't use often (like a generator or pressure washer) I make sure to run it out of gas when I'm done with it.
 

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,082
Reaction score
7,756
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
Running it out of gas is the best bet on small engine stuff.

Whether it’s jets or injector orifices, ethanol can be problematic. Only difference is a carb is more easily user serviceable.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
I run ethanol free in all of my small engines. I've never had an issue with varnish in any of my regular engines though. My truck will sit for extended periods of a few weeks sometimes, and I've never had an issue. EFI engines need the injectors cleaned every few hundred thousand miles... but carbs need to be rebuilt in the same mileage or less also. I have almost 300k miles on my 93 Honda and the injectors cleaned up no problem. 240k on my 2011 Suburban with flex fuel and no issues. I run E85 when I can on my suburban when towing because it provides vastly superior performance for high horsepower or heavy duty applications.
 

BlazerBill

Full Access Member
Joined
Mar 24, 2023
Posts
103
Reaction score
83
Location
Texas
First Name
Billy
Truck Year
1983
Truck Model
Chevy K5 Blazer
Engine Size
350
Thanks for the replies! I let my pressure washer run out of gas the last time I used it 3 weeks ago and the jet was still plugged up. So, EFI/TBI injectors have the same problem with ethanol fuel, is what you’re saying? Are people that are running aftermarket EFI/TBI having to use injector cleaners on a regular basis? I don’t hear of many complaints with factory EFI or even with my new cars. The injector cleaners I’ve used proactively on my new cars didn’t seem to have any noticeable difference.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Thanks for the replies! I let my pressure washer run out of gas the last time I used it 3 weeks ago and the jet was still plugged up. So, EFI/TBI injectors have the same problem with ethanol fuel, is what you’re saying? Are people that are running aftermarket EFI/TBI having to use injector cleaners on a regular basis? I don’t hear of many complaints with factory EFI or even with my new cars. The injector cleaners I’ve used proactively on my new cars didn’t seem to have any noticeable difference.
No, I drain my big generator of all fuel and then run it dry because I know it could be a year or more in between times it runs. As I said in my previous post, I have zero issues with any of my stuff gumming up. Stabil will keep the ethanol from messing stuff up and the gas from separating or going bad for 6 months to a year no problem. Maybe you have some junk in your fuel cans or you are doing something strange, because I've never had an issue with any of my vehicles or equipment doing that. That includes a pressure washer that had half a tank of fuel in it for over a year(over the winter even), out in the PNW weather, and still fired right up and ran good on the first pull this last saturday.
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
4,192
Reaction score
8,030
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
This e0 just started showing up recently. Going by the name Clear Gas.
 

Attachments

  • IMG_20240426_081530437_HDR.jpg
    IMG_20240426_081530437_HDR.jpg
    149.6 KB · Views: 36

squaredeal91

Full Access Member
Joined
Mar 10, 2023
Posts
2,534
Reaction score
4,583
Location
Cave junction Oregon
First Name
Greg bush
Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
Bill How are you cleaning your main jet? And What make is the engine?
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
6,970
Reaction score
12,220
Location
Auburn, Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
I’d look elsewhere for the cause of your universal “ethanol” problem.
There are plenty of reasons that pure gasoline is better in many circumstances and even more myths.
Pure gas will varnish up eventually too. Neither E or No E gas will do that in weeks or even a few months under normal circumstances.
E10 or ethanol in general, absorbs moisture. Far less of an issue in TX than other places.
Ethanol is more corrosive and/or a stronger solvent. It could be eating up old rubber lines and hoses, slowly which could be part of your issues.
Assuming these have been repeatable occurrences, your fuel storage containers or old fuel lines (in the truck) or ???? Are likely where you should concentrate.
Ethanol is not as evil as some pretend it is, however it does have some disadvantages that are more of an issue than pure gas when fuel begins to age or is stored questionably.
If its varnishing up you think in that short of time, you’d smell it.
And if it has kept happening repeatedly, did running pure gas cure it?

Sometimes random weird stuff happens. In your case, struck that gets filled at the gas station with lots of gallons vs a small tool that may be fed out of the same gas can for months, doesn’t make sense to have the same symptoms.
To the random weird thing , had a metal 2 gal can I used for the small 2 smoke engines. Always AV gas and quality oil. Somehow that can went sour and it would ruin a batch of quality premix, twice. Inside of a month, blue gas with blue oil (so it’s really blue, lol) would look and smell like it has been sitting in a junkyard gas tank for years…

Back to the smell, if it don’t smell right, don’t use it! (Could be said for many things….lol)
Be honest with yourself, if you were putting fresh month old gas in everything and burning it up in a reasonable amount of time, you almost assuredly wouldn’t be having frequent and multiple issues.
 
Last edited:

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
I feel bad for folks who have to live by Cali rules.
True for many things.. but the one thing that has lately gotten me a little jealous is the lack of stations having E85 up here. Cali has a ton of stations, mostly central california and south of there, that have either mixer pumps or straight E85. It would be doubly nice if I could get a mixer pump in town to run E30 or so. Better mileage, cleaner running, and more power everywhere in the curve with E30. If you just want max power or are putting in heavy towing duties.. E85 makes a world of difference, but mileage suffers for it also.
 

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,082
Reaction score
7,756
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
I thought e85 only helps if you need it with super high compression or boost? It’s actually less energy dense otherwise…
 

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,082
Reaction score
7,756
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
Far less of an issue in TX than other places.
If Billy is near the gulf coast, I could see e10 turning bad relatively quickly there.
 

Latest posts

Forum statistics

Threads
44,163
Posts
950,649
Members
36,276
Latest member
2manysquares2care
Top