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Boiling a carburator

Posted by andyma z6?MA (My Page) on
Sun, Feb 8, 09 at 9:14

I have a couple of Tecumseh carbs to rebuild. A guy I know suggested boiling them in water to loosen the varnish. Has anybody tried this or similar procedures to clean stuff? I dont want to spend 20$ on the dip stuff or an ultrasonic cleaner.

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RE: Boiling a carburator

  • Posted by canguy British Columbia (My Page) on
    Sun, Feb 8, 09 at 12:43

Water will not help much by itself. Spray them thoroughly with a good carb and choke cleaner then rinse them in varsol or paint thinner, NOT gasoline.

RE: Boiling a carburator

Do they still make the 'good stuff' anymore?
In a previous life I used to rebuild Rochester
carburators and I would soak them in GUNK carb.
cleaner overnight and they would come out looking
like brand new. But, the fumes would kill you.

RE: Boiling a carburator

I restore vintage motorcycles for a hobby and commonly "boil out" carburetors.

Here's what I do:

Use about 1 cup of WHITE vinegar to a couple of quarts of clean water, enough water to cover the parts (more or less vinegar, the exact amount is not critical). Strip the carb down to it's smallest individual components, being especially careful to remove the rubber parts and gaskets. Do *not* soak the rubber parts or gaskets, set them aside.

Place the carb parts into the vinegar solution and bring the mix to a soft rolling boil on the stove (it will smell a bit, so be prepared for this). Maintain this rolling boil for about 45 minutes or so, adding water if necessary to keep the parts covered.

After the initial 45 minutes, drain and replace the solution with clean water. Bring the water back to a soft rolling boil for another 30 minutes or so to rinse the parts.

You'll find the parts will be covered with a soft white powder... this is normal and it will brush off easily with a soft toothbrush or something similar.

Blow out the passages with compressed air and you'll be good to go.

Note this will *not* damage metal parts of any kind, including castings and brass.

RE: Boiling a carburator

Interesting kwright5. Some of the issues w/ the Tecumseh carbs pertain to not being able to effectively get at the passages to blow out or manually clean. Same with the carbs you do this with?

Andyma- I remember the farmers tossing the carbs in diesel fuel to soak. The $20 Gunk isn't the cure all. I used to get Hydroseal, but that got toned down I'm sure as regulations went into effect. I have met old time mechanics that washed everything in harsh parts cleaner that ended up regretting it, so I understand the regs.

RE: Boiling a carburator

I've worked on just about every brand and type of small carburetor made, domestic, Japanese and European. The problem of cleaning the passages is universal.

I occasionally use - if I deem it necessary or as a preventative measure - very fine copper wire to thread though the passages.

I take a piece of fine stranded wire, say similar to that used in a motorcycle loom (18 gauge or so) and strip the insulation. Unwind the wire and separate out a few a few strands, the number of strands used depends on how large the orifice is you need to clean. Twist these strands back together tightly, and use as a tool to clean the passage(s). I have a virtual unlimited supply and can make them as long as needed.

I've heard it told that this may damage the carb, but I've done dozens this way, and using the copper wire, which is soft, and a bit of care, you'll be fine.

RE: Boiling a carburator

The rebuild kit for the Tecumseh came with a couple of welch plugs. I have never bothered R+Ring these before. The guy I bought the kit from said he doesnt either. But the carb I want to rebuild must have gotten wet and the plug is rusty. Any advice? TIA

RE: Boiling a carburator

The plug in the bowl or the one on the outside of the carb?
Well no matter, I suppose you'd want to replace both anyhow.
Tap a sharpened file nub or a very small screwdriver into the plug and pry it out.
Work slowly and carefully, make sure you go really shallow.
It's easy to ding the carb on the outside plug.
Re-install by tapping new plug in with a drift until it's snug and has a flat spot.
Then seal the edges by painting with clear nail polish.
I suppose you could use pink but it's not very butch.

BTW -kwright, have you ever successfully freed a metering rod in an idle circuit with your boiling brew?

RE: Boiling a carburator

To remove the Welch plug, I'd follow boltonranger's advice.

To answer your question boltonranger, regarding a pilot or idle circuit jet, I have run into one or two over the years that virtually defied any method of removal... including boiling (thought boiling usually works).

When I run into a very-tough-to-remove jet, I resort to heat. I clamp the carb in a vice between two planks, and break out the propane torch. I heat the body nearest the jet as hot as I dare (use care), then allow it to cool completely, naturally. I typically repeat this cycle a number of times - heating, totally cooling - heating, etc. After three or four cycles, I'll try to remove the jet after the cool down. If it doesn't budge, I'll do it a few more times. I've spent the better part of a day doing this, off and on, and I can only recall one case where I ultimately wasn't able to get the jet out. The brass screw driver slot stripped out and frankly, I believe I pushed the process too hard and blew it.

RE: Boiling a carburator

Thanks all, I did a 1/2 @$$ refresh of the carb using essential parts from the kit. I replaced the main jet and the idle jet. Then I replaced the airbox that I had been running without. Big difference, the engine is no longer bogging under load. There is a little pop still left to the exhaust, but that is to be expected in a 35 yr old engine KWright5, I intend to try your method in the future though.

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