Carb Cleaner


#1

I have noticed that regular fuel left in a carb without use for a while (5-6 months) will develop varnish. I believe this is because of the ethanol in the fuel. When removing carbs for small engines that are contaminated what liquid can be used in order to soak the carb and have the varnish dissolved? Also how long should a carb be soaked to clean it this way? Any other advice is appreciated.


#2

You can buy carb cleaner at auto parts stores. You can also prevent the buildup of varnish (which is NOT from ethanol) by adding fuel preservative to the gas before you pour it into the tank. Preservative (such as StaBil) is also available at auto parts stores.


#3

Yeah, what he said. Use commercial carb cleaner, ethanol is not the culprit, maybe fuel stabilizer will work.


#4

I believe this is because of the ethanol in the fuel.

Ethanol is NOT the problem. Varnish has been a known problem LONG before ethanol was ever used.

On lawn mowers or snow blowers I always run it dry at the end of the season to prevent varnish. I know it’s near impossible to do with a car. And when varnish does happen it can really cause some problems. A good carb cleaner will do it…but it’s has to be a fairly high concentrate.


#5

Ethanol is not the cause. Regular gasoline does the same thing.

The proper way to clean and/or overhaul a carb is to use carb cleaning solvent (called acid by techs) that is sold at most car parts stores in 1 to 5 gallon canisters.

The carb should be disassembled, put into the basket, and allowed to soak for a minimum of 1 hour.
Remove the parts, wash everything thoroughly with water, and then use compressed air to blow out all passageways and dry everything out.


#6

My coworker told me about a generator he worked on where the gas had been sitting for at least 5 years, but fuel stabilizer was used. He said the fuel still deveoped varnish, but the stabilizer kept it from sticking to anything.


#7

Fuel stabilizer is not designed to make fuel last FOREVER, just longer than without stabilizer. A year, or two at most, is as much as you can reasonably expect with stabilizer.


#8

My coworker told me about a generator he worked on where the gas had been sitting for at least 5 years, but fuel stabilizer was used. He said the fuel still deveoped varnish, but the stabilizer kept it from sticking to anything.

Well I guess he means well. The stabilizer reduces the rate that polymerizing takes place making big molecules (varnish) from small ones.


#9

I’ve cleaned many carburetors, both automotive and small engine. The advice ok4450 gave is on the money.

The snowblower carburetors tended to varnish up the most. I think because they sat in “hot garages” during the summer months. Lawnmowers, which sat in “cooler garages” over the winter months, tended to varnish up less.

Even though we tried telling customers to use fuel stabilizer, many never did.


#10

Joe, in addition to running the fuel systems dry for seasonal lawnmower/snowblower changes I also add carb cleaner to my lawnmower/snowblower gas in about a 1oz per gallon of gas ratio. It works syrprizingly well, even having gotten an old sputtering snowblower running well after a few tankfuls.

  • mountainbike

#11

I’ve been using lacquer thinner for years to clean carbs; is much less expensive than carb cleaner and does the job.

We run the snowblower carb enpty in the spring and drain the tank and it starts like nothing happened withf fresh gas. The motorcycles and riding mower are parked from Nov to April. I can run the carb dry on one but can’t on the other and the riding mower. The other and the riding mower start with some reluctance in the spring but always do. I use lead free gas with no alchohol. Lead free with no alcohol is less troublesome for parked engines for me than leaded gasoline.

The reason that engines start hard with gas left in the carb for months is not varnish, in my view, but is because the more volatile portion of the fuel evaporates off, making starting difficult.

I don’t use Sta-Bil; consider it to be snake oil.


#12

The problem with lacquer thinner is that some carbs use this very soft metal…Carter carbs were for years…And the lacquer thinner tended to actually etch the metal.