Recommendations for a fuel additive for old gas/gummed up carburetor

Ranger Dan

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Aug 31, 2003
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York PA
I inherited a rototiller when we bought our current house a few years ago. I'm not a gardener and I'd like to sell this on craigslist. I can get it to start by spraying starter fluid into the carburetor, but it sputters out once the starter fluid is consumed. I'm guessing that whatever gas in the tank is "bad" and the carburetor is gummed up. I know that there are more than a few options for fuel additives to remediate bad fuel and/or remove varnish from the carburetor and needle valve. Do any of you have any specific products that you can recommend?
 

Limestone_Lion

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Aug 26, 2016
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Go to any parts store and look at the Lucas oil lineup. They make the best products out there for vehicles
 

Delco Lion

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Feb 16, 2017
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Same thing happened to my riding mower. Had to get a new carb. The guy who fixed it rec I add Star Tron Enzyme Fuel Treatment to my 5 gal gas container.
 

cment

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Jun 1, 2006
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My go to for this situation is Seafoam. Empty the fuel, and refill 1/4 tank with 4oz and let it run as long as possible. Repeat until you are fustrated then you move on.
If the carb or lines are gunked, you will probably need to yank the carb, replace hoses, and clean or replace the carb. For storage I would recommend adding Star Tron and a little Seafoam and then run the machine dry.
 

paulrandythomas

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Jul 24, 2006
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I inherited a rototiller when we bought our current house a few years ago. I'm not a gardener and I'd like to sell this on craigslist. I can get it to start by spraying starter fluid into the carburetor, but it sputters out once the starter fluid is consumed. I'm guessing that whatever gas in the tank is "bad" and the carburetor is gummed up. I know that there are more than a few options for fuel additives to remediate bad fuel and/or remove varnish from the carburetor and needle valve. Do any of you have any specific products that you can recommend?

Old grandad
 

Ranger Dan

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Aug 31, 2003
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York PA
Same thing happened to my riding mower. Had to get a new carb. The guy who fixed it rec I add Star Tron Enzyme Fuel Treatment to my 5 gal gas container.
I'm not going to rebuild the carb... I'm just trying to get it running enough to sell it.
 

Ranger Dan

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Aug 31, 2003
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What I'm looking for is something to keep me from draining the fuel tank and/or rebuilding that carb.

I may give the Berryman B-12 Chemtool that Art recommended.
 

asbury park

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Jul 8, 2001
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Sorry Dan but some of those carbs get to bad they need to be rebuilt. Went through this with an old Deere. You can try all the additives you want but t won't change the way a messed up carb functions. Probably isn't just the carb either. The whole fuel system likely has issues if the gas has been sitting for a while.
 
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Ranger Dan

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Aug 31, 2003
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York PA
Sorry Dan but some of those carbs get to bad they need to be rebuilt. Went through this with an old Deere. You can try all the additives you want but t won't change the way a messed up carb functions. Probably isn't just the carb either. The whole fuel system likely has issues if the gas has been sitting for a while.
As I said before, I'm not tearing anything apart or rebuilding anything. I'm looking for the best option to clean out whatever mess is in the fuel system in order to get the thing to remain running for more than 5 seconds....
 

Ct. Lion

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Oct 25, 2002
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I would attempt to get the old fuel out of the tank and add some fresh fuel. For outboard engines that are "fussy" I add some Star Tron and then some Sea Foam. A roto tiller engine is nothing but a small 4 stroke outboard engine. Then some Marvel Mystery Oil in the gas after the engine is running again.
 

Peetz Pool Boy

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Jun 11, 2014
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My go to for this situation is Seafoam. Empty the fuel, and refill 1/4 tank with 4oz and let it run as long as possible. Repeat until you are fustrated then you move on.
If the carb or lines are gunked, you will probably need to yank the carb, replace hoses, and clean or replace the carb. For storage I would recommend adding Star Tron and a little Seafoam and then run the machine dry.
You've given the best advice, but somehow the "poster/owner" desires a "quick fix" :rolleyes:
 

demlion

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Feb 4, 2004
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Take some paper towels and roll them up in a cylinder about 18 inches long and thick in the middle. Jam one end in the bad gas, and the other end in a bucket, but not touching the bottom of the bucket. Through the magic of capillary action, the gas will travel through the paper and drip into the bucket. An old sheet will work even better.

Once the gas is all, or almost all out, then use your additives described here. I would use Seafoam, but just use one of them. I would buy some premium gas and put in a quarter to half a tank. Try it. If no start, try a new plug. If that won't work then you're done unless you tear it apart.

I have also just turned them over to get the old gas out. But that can get messy.
 

c141nav

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Nov 25, 2007
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Pull the brass nut out of the bottom of the carb and remove the bowl. At the bottom of the venturi tube will be two tiny holes, Stick a pin through them to clean them out. Make sure the float is not stuck in the up position. Replace the bowl as it was originally. Put fresh fuel with SeaFoam in the tank and see if the engine will start. If it does let it run through an entire tank of fresh fuel and Seafoam mixture.
 

sluggo72

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Aug 31, 2006
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Star Tron sea foam thingy is the way to go. Changing the plug is simple n will probably help too. Dumping some new gas right in the carb should get it going too.
 

Nittany Ziggy

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Dec 10, 2003
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Pittsburgh
Take some paper towels and roll them up in a cylinder about 18 inches long and thick in the middle. Jam one end in the bad gas, and the other end in a bucket, but not touching the bottom of the bucket. Through the magic of capillary action, the gas will travel through the paper and drip into the bucket. An old sheet will work even better.

Once the gas is all, or almost all out, then use your additives described here. I would use Seafoam, but just use one of them. I would buy some premium gas and put in a quarter to half a tank. Try it. If no start, try a new plug. If that won't work then you're done unless you tear it apart.

I have also just turned them over to get the old gas out. But that can get messy.
Thanks for sharing this tip. You seem pretty handy around the power tools! ;)
Seriously, this is a good tip and I wish I had read this before winterizing the snow blower that I used for 10 minutes this winter. I will refer to this technique as "The Tampon Method" from now forward.
 

Fayette_LION

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Jan 28, 2004
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As I said before, I'm not tearing anything apart or rebuilding anything. I'm looking for the best option to clean out whatever mess is in the fuel system in order to get the thing to remain running for more than 5 seconds....
Ranger Dan, there's a hose from the tank to the carb. Take it off and drain the old gas out. Put new high octane gas in it and see what you get. Very little to do but remove one hose clamp. It's worth a shot. If you get it to run half decent, then dump some carb cleaner in the tank and try to run the hell out of it.
 
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demlion

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Nitt1300

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sell it as is- anybody who knows enough to fix it will just want to know if it turns over - since it does somebody will be interested
 
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PSUTENN1

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May 23, 2004
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I inherited a rototiller when we bought our current house a few years ago. I'm not a gardener and I'd like to sell this on craigslist. I can get it to start by spraying starter fluid into the carburetor, but it sputters out once the starter fluid is consumed. I'm guessing that whatever gas in the tank is "bad" and the carburetor is gummed up. I know that there are more than a few options for fuel additives to remediate bad fuel and/or remove varnish from the carburetor and needle valve. Do any of you have any specific products that you can recommend?
With the stupid addition of corn oil to gasoline this is a very common problem. First, add "Sta-Bil" to your gas storage cans. Sta-Bil can be found anywhere and it is an excellent product.

Second, instead of waiting for a "fuel cleaner" to work, which it wont, take the brass nut off the bottom of the carburetor bowl, that's the fuel pick up for the high speed jet. That nut is hollow, you will find your gummed problem there. Use a thin wire (most times a paper clip is to big) and clean the gum out of the orifice of that bowl nut. Run the thin wire up though the hollow little tube that extends into the bowl.

Walla, it's running good again.