Easy and Almost Free Way to Stop Leaky Carbs

Braaaptor

Member
Dec 1, 2009
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Hamlet, NC
Ok, so we've all probably been there... You go to turn on the gas to the Blasty, and all of a sudden it starts spilling out of the carbuetor, either through a vent tube or the intake. Here's a little-known trick to solve the problem, using only materials found in the bathroom. Read on, this takes about 10 mins and costs almost nothing! Oh, and for all the cynics out there who can't understand why you don't just go out and buy a carburetor kit for $ 15.00 that comes with a whole new needle and seat? Relax.

$ 15.00 buys a lot of double cheesburgers and Cokes, and why go buy parts you don't need? Plus, it is way too easy for inexperienced riders to accidentally install the stock jets which come in most carb kits, thereby undoing lots of time spent jetting the bike in the first place. Oh, and how many people carry a spare carb kit in their back pocket while out on the trails? Didn't think so. If you're a camper such as myself who cares at least some about hygene, you need look no further than the personal care bag in the truck for some toothpaste and a couple Q-tips...

To do this DIY, you will need said leaky carburetor, a couple shop rags, a good clean work surface, a can of carb cleaner, a couple cotton swabs (Q-tips), and a tube of paste-type toothpaste. :-/ Yup, just trust me. This little-known trick works wonders!

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First, get the offending carburetor off the Blaster. It helps to open the bowl drain screw before taking the carb off to avoid spilling even more gas out.

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Take the carb, invert it on your workbench, and take the bowl off. Remove the main jet splash shield and set it all aside. Watch out for gas which may be left in the bowl. Rags help here.

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Next, remove the pin holding the float in place with a pair or long-nose pliers or a small roll pin punch. Be VERY CAREFUL with the punch so that you don't break one of the float pin-holding 'ears' off the carb. Take the float off and look it over carefully. Shake it. If you see any pinholes or hear gas sloshing around inside the float, it is no good and will have to be replaced. The carburetor you are working on is a Float Carburetor. Not a Sink Carbuetor.

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Float OK? Good. Set it aside and look at the needle. This needle has a rubber tip which works in combination with the brass seat bolted inside the carburetor to shut off the fuel flow to the carburetor when the bowl becomes full. If the needle becomes damaged or debris gets between the needle and the seat, the needle can't do its job and you get a flooding problem.

Look carefully at the rubber tip on the needle. If it is bent, badly grooved, or noticibly damaged, you will need to replace the needle. A small amount of deposits can be cleaned off as instructed later.

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Now, take a cotton swab and put a small amount of toothpaste on it. Slide the swab into the seat and work it for about 30 seconds.

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Pull out the swab, turn it over, and use the other end to do the same.

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By now, you will probably see that the swab has turned black where it touched the seat. There's all the deposits which were encrusting the seat cleaned off! Some carbs are so bad that even a new needle wouldn't seal against a dirty seat.

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Once you have the seat clean, it will be shiny clean and look something like this. Do the toothpaste swab again if needed, until it is nice and polished.

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Now, if your needle isn't totally shot, do the same thing to the rubber tip of the needle. Get it clean, and don't forget to get all the toothpaste out of the carbuetor before putting it back together.

Next? Simply clean out the remainder of the carb with aerosol cleaner as needed and put it back together. Be sure to check the bowl gasket before reassembly, as a stale or damaged bowl gasket will result in a fuel leak around the bowl. Usually more of a drip than a gush, but I've seen some carbs with bad bowl gaskets take a rather nice pee.

With the carb back together, simply put it back on the Blasty, turn on the fuel, and ride away leak-free! I can't 100% guarantee that this will work on EVERY carb, but this trick has worked well for me and has put an end to many headaches. It is also very handy to know when working on carbs with pressed-in seats that can't be easily replaced. I recently rebuilt the carb on a Honda Recon for a neighbor, and his carb wouldn't quit spewing fuel until I broke out the Colgate. In the case of that carburetor, you would have to buy a whole new one if you wanted to replace the seat.

Also, I LOVE doing the toothpaste treatment to troublesome carbs on riding lawn mowers. Newer Kohler and Briggs and Stratton 25-, 28-, 30-, and 33,000 model series engines, especially, seem to suffer from incessant flooding problems. On them, the carb usually leaks during storage and fills the whole engine up with gas. Here's a quick cure for those carbs, too, without having to go out and pay $ 100.00 or more for a new one, even after you've put in a new needle and it still doesn't solve the problem.
 
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WOW! That is the dirtiest carb I've ever seen! I can't believe it even ran! How did all that chit get in there , no filter? Cool right up, But I'm not sure about the tooth paste, Q-tip however. I just use carb cleaner and compressed air. Also I remove the choke, air screw and spray carb cleaner in every orfice, then comprressed air, However This carb looks like it was never cleaned so probably needed special attention.
 
WOW! That is the dirtiest carb I've ever seen! I can't believe it even ran! How did all that chit get in there , no filter? Cool right up, But I'm not sure about the tooth paste, Q-tip however. I just use carb cleaner and compressed air. Also I remove the choke, air screw and spray carb cleaner in every orfice, then comprressed air, However This carb looks like it was never cleaned so probably needed special attention.

Yup, you're right, Slick! Actually, I just cleaned the seat on this carb for the purpose of this DIY. The Blaster from which it was removed needs lots of TLC and will not be running for awhile. I need to vat and put a kit in this demo carb before it will be able to sustain an engine. Lol, I just got in a hurry to get this posted. No idea what kind of gunk that is in the bowl. I'm thinking cheap mixing oil that stayed in there way too long.

Cleaner and compressed air work great most of the time, but sometimes the gasoline reacts with the brass seat and form a layer of deposits so thick that carb cleaner and compressed air alone won't get rid of them. This is where the toothpaste helps. And you know it's not gonna hurt the carburetor...not when the mild abrasives in there are designed to go in one's mouth...
 
good stuff bro, have some greens !!!!
 
nice, but ya clean the main jet please.
also i leave my carb overnight in this one degreaser stuff, works wonder on getting all the gunk and sh*t loose for the carb cleaner.
 
Thanks for the info... couldn't figure out what was making my carb leak and then i read your post about the needle..

If it is bent, badly grooved, or noticibly damaged, you will need to replace the needle.

low and behold the tip of the needle had a nice ring indent causing it to not seal properly and leak... replaced the needle, no more leak... thanks again I:I
 
Have some green for writing up something I've done for years. Nice job.

That green sh*t in the bowl is a sticky smelly form of varnish. That carb sat A LONGGGGG time. The gas breaks down over time and becomes a varnish like substance. And can be very difficult to get off. I imagine the choke circuit that carb is clogged solid
 
Have some green for writing up something I've done for years. Nice job.

That green sh*t in the bowl is a sticky smelly form of varnish. That carb sat A LONGGGGG time. The gas breaks down over time and becomes a varnish like substance. And can be very difficult to get off. I imagine the choke circuit that carb is clogged solid

Thanks! I'm sure this carb will need a nice long bath in carb cleaner to get it back to running condition. I may not even bother cleaning it and just thow on and re-jet a good used 28mm PWK instead.
 
Thanks! I'm sure this carb will need a nice long bath in carb cleaner to get it back to running condition. I may not even bother cleaning it and just thow on and re-jet a good used 28mm PWK instead.

I use this stuff I get in pep boys. Chem Dip. Its a gallon paint can with a basket in it. Throw the parts in it ove night and strips them clean. Couple tips.
Remove all o rings or rubber cuz it will disintegrate them. If you soak the body, dont leave in more then an hour. It's cheap pot metal and the cleaner reacts to it the bowl is ok ok. It will make those jets shine like new.
Most auto stores have it. Look by the carb cleaner stuff but around here it's always buried on a bottom shelf

We rebuilt a basket sportster last year. Carb was s bad with that goo I bought a hydro sonic jewelry cleaner from harbor freight. Now that works great but slow. Had to leave parts in for a week. But it won't attack o rings or pot metal
 
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I use this stuff I get in pep boys. Chem Dip. Its a gallon paint can with a basket in it. Throw the parts in it ove night and strips them clean. Couple tips.
Remove all o rings or rubber cuz it will disintegrate them. If you soak the body, dont leave in more then an hour. It's cheap pot metal and the cleaner reacts to it the bowl is ok ok. It will make those jets shine like new.
Most auto stores have it. Look by the carb cleaner stuff but around here it's always buried on a bottom shelf

We rebuilt a basket sportster last year. Carb was s bad with that goo I bought a hydro sonic jewelry cleaner from harbor freight. Now that works great but slow. Had to leave parts in for a week. But it won't attack o rings or pot metal

^^Good info! I've been using those pails of Chem Dip for years, ever since I vatted my first Briggs and Stratton carburetor back when I was 10 years old.

It works great, as long as, like you said, no plastic/rubber or pot metal is left in there too long. I learned that the hard way... a couple rubber throttle shaft seals once disappeared...I pulled the carb out of the basket and figured "Oops! Must've forgotten to remove something!" :D

In this case, I just want an excuse to upgrade carbs! ;)
 
I just picked up a Blaster that hasn't been started in 2 years. Before I try to start it I'll try your toothpaste carb cleaning.
Thanks for the write up............
 
thank you guys verry helpful tip there, never thouhgt on using toothpaste on carb to clean it out rep points for u for ur helpful tip, thank you againd