# "varnished" carburetor...next step?



## wrencher2b (Feb 19, 2005)

I've got this lightly used (no carbon on piston head) Sears brushcutter that has been sitting since 1992. The fuel tank had a tablespoon of varnish and the fibrous fuel filter was hardened with the same stuff.

The tank has been cleaned, the fuel filter and the fuel lines replaced.

Because of the fuel systems' prior condition, i'm assuming that the carburetor is also varnished up. Would it be a good move to use a carburetor cleaner (straight or blended with gas) in the fuel tank, remove the spark plug, ground the spark plug wire connector and by repeatedly pulling the pull-cord, attempt to "pull" the cleaner through the carburetor? ...Eureka, a cleaned out carb!!!???

The option of soaking the disassembled carb in cleaner and rebuilding it with new diaphrams and gaskets from Sears.com is, to me, excessively expensive and a last ditch choice, at best.

Any opinions out there?


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## hankster (Jan 1, 1998)

You didn't say what model you have but I will assume it has a Zuma or a Walbro carb. You'll never get it cleaned out by "pulling" on the recoil.

At the very least you may be able to pull the cover on the fuel inlet side (single screw) and be able to clean the inlet screen. Also pull the adjustment screws and clean everything well with carb cleaner. That may or may not allow you to start it.

If that doesn't work then most likely your diaphram is brittle and will need to be replaced (my guess) and at this point you might as well get a rebuild kit because most likely the other gaskets and stuff are old a dried out too. The carb may even need a good soak.

The only way to know is to tear into it and see how bad it is... I've seen 'em so bad it looks like epoxy was poured into the carbs and there was no way to save 'em.


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## bugman (Aug 12, 2004)

yeah you can't really go about a carb the easy way, if it has been since 92 hell i'd go ahead and rebuild it because of that, but with gas sitting in it that long, most likely all the little holes are stopped up shut and the diaphram is shot. i would by a cheap glad ware bowl or something you don't care about thats hard plastic and closes up, put the disassembled carb in it and fill it up over the carb with either bought cleaner or carb cleaner out of a can and let it sit for a long time, over night maybe. buy a rebuild kit and blow the carb fully out and make sure its good and clean by air or by blowing it out with cleaner, then let it dry totally first, then rebuild it with the kit and you should be all set. reason why you don't want to have cleaner on it, it will hurt the seals etc when going back on.


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## scrench (Dec 8, 2004)

put a kit in it , be sure to seal off the welch plug in the carburator finger nail polish will do the trick but for sure you will have to put a kit in it and clean it verry good , we will walk you through the kit verry easy and might make a good sticky like said before be sure you post what kind of carburator it is probally a walboro


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## bbnissan (Nov 7, 2004)

I have to agree with everyone else...rebuilding the carb is your only option because the diaphram is probably stiff as a board.


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## wrencher2b (Feb 19, 2005)

:thumbsup: 

Thanks, all, for your input.

This Sears brushcutter has a T-K carburetor with a "tickle valve" on the bottom. It's different from any other 2-cycle carb that I've seen.

I should have been more clear in posting my original question. Because I
have only located parts for this carburetor at Sears (not as a reasonably priced kit, but each gasket, diaphram etc. is priced separately...$$$$$+S&H).

Therefore, what I want to do is attempt to get this older equipment running without putting unnecessary money into it. That's the reason I'm asking about filling the fuel tank with a light carburetor cleaner/fuel mix and if necessary priming the carb with a little starting fluid to pull the fuel/cleaner mix through the carb until it initially runs on it own...and then shut it off, immediately.

Finally, I would empty the fuel tank and lines and let the new "mix" sit in the carb for a day or so, to soak the internals before rujnning it on regular fuel mix.

Any more thoughts on this plan of action?


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## bugman (Aug 12, 2004)

still needs a diaprham and gaskets for it to even run correctly. there is no quick fix for a carb that age, and on top of it gas sitting in it, gumming it up and rotting all of it out. reason why, the diaprahm is basically rock hard and un able to pass fuel and when ou do take the carb apart the gaskets may split, if you run cleaner through it it may make the whole thing just leak like crazy due to the gaskets being dry, the carb cleaner basically will make things worse then they are with no rebuild.


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## hankster (Jan 1, 1998)

As was said, there most likely is no way around it other then tearing the carb apart and cleaning it. When you take it apart you most likely with tear up the gaskets. No amount of "letting gas sit in the tank/carb" will clean out a carb that is varnished up. Once you tear it apart and look at (and clean) the inlet screen you'll see what we mean... now just think of all the same crap throughout the rest of the carb...


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## scrench (Dec 8, 2004)

that kit should not cost over eleven or twelve dollars @ the most ,,, g o to a sm all engine shop and tell them you want one from oregon (used to be silver streak_) 

you might get by with trying to loosen up the diaprham with some brake fluid of kerosene or soak it in 2 cycle oil for a couple hours ,, then kinda roll it in your fingers to loosen it up but i would spend the money on the kit , get you some new fuel line and fuel filter and a new plug and tune it up right , the other diaprham , is probally going to a different story i have never seen one come apart without tearing the gasket , you will get the o-rings you need also .


{hankster} , sounds like this thing might be related to the shindiawa like you touched on in another thread , sounds like a shindiawa carburator to me ? ...........


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## hankster (Jan 1, 1998)

scrench, could be. We've had a few of them in and I didn't know what kind of motor it was until one of the old timers told me.


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## wrencher2b (Feb 19, 2005)

Thanks, guys.

One thing that I've just learned is, definitely, notto use carb cleaner in this application.

The carburetor is a T-K brand and BBNissan has determined through his extensive search that even though Sears.com has Echo has the supplier, that there is no ECHO brushcutter with this carburetor. Another website, known to BBNissan, states that this is a Robin Trimmer engine. BBNissan agrees. As no carb kit is available through my normal supplier (Stens), I've only found the various diaphrams and gaskets separately through Sears...$20-$25 including S&H. Because of the age of this brushcutter and its lineage, I don't want to get nickel and dimed to excess.

I found a small washer jammed between the armature and the magneto(?), preventing me from pull-starting it. Upon removal, I elected upon using a short burst of starting fluid and attempting to start the brushcutter. Three tries and this thing started right up. 

Because it won't go to a regular idle, but runs only at approx 2000 rpms or higher, I need to figure out what is causing the throttle valve to be held open(?).
Also, what purpose is the "tickler valve" on the bottom of this T-K carburetor?

Any ideas?


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## hankster (Jan 1, 1998)

Could be two reasons to the no idle condition. One is a plugged low speed circuit on the carb. Second is a "stiff" diaphram. The tickler valves are normally just to bleed out a little fuel and any gunk that may be sitting in the bottom of the bowl.


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## wrencher2b (Feb 19, 2005)

I realize that I should have stated the idle problem more clearly.

Upon getting this brushcutter running, it only runs at approximately 2000 rpms or much higher (as it should). However, the idle adjustment screw has no effect on the rpms. In other words, the approximate 2000 rpms is as low as it goes. 

Upon removing the air cleaner, I noted that the "valve/piston" in the carburetor bore appears to be in a partially opened position. This is purely conjecture on my part, as I have no duplicate carburetor to compare it to.

"Hangster", given the preceeding information, does your most recent post still hold?

*****UPDATE*****

I can finally put the question of the Sears "BrushWacker" (51.7cc) ancestry 
to rest. In the Intertec book "String Trimmer and Blower Service Manual-2nd Ed, on page 124 it plainly shows the brushcutter, in question, with its handlebars and unique "carry handle". On page 119, it states that this is a Robin unit, (model NB50L). It has a Fuji engine (model EC05). (Therefore, at least two web sites that listed this unit as being manufactured by ECHO were entirely inaccurate.)
Sorry, "BBNissan" for all of your extra effort expended. However, in the end you were entirely correct in determining that this is a Robin trimmer.

Hopefully, this thread will help some future reader/"BrushWacker" owner with his, similar, search for knowledge.


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## hankster (Jan 1, 1998)

Have you tried adjusting the idle setting?


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## esc crazy (Mar 16, 2004)

I just stumbled onto this thread after doing a search on my Brushwacker. My dad bought it new around 1992. We used it many years and he finally gave it to me 4-5 years ago. This thing is the most wicked weed trimmer/brushcutter I've ever seen. It's market by Sears and made in Japan. It's a straight shaft (stainless supported by several large bearings) trimmer with a handlebar like design. The engine is around 38 cc and it's not like anything I've ever seen. It has a 1 qt. fuel tank on top of it and the most unique thing to me is the carb. It's a Mikuni sidedraft carb with a very large port (compared to others). I'm looking for info as to who made this piece of equipment. After about 13 years of use it still runs like new and beats anything I've ever used. It reminds me of the saying "they don't make them like they used to", and they sure don't. Later!


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## hankster (Jan 1, 1998)

It is manufacturered by C. Itoh/Robin. C. Itoh was an engineer for Subaru and started making his own small engines. It was then bought out by Robin if I am not mistaken.


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## esc crazy (Mar 16, 2004)

Thanks for the info. Is that brand of engine supposed to be of high quality or unique? I've used a decent number of weed trimmers/brushcutters in my life, but none compare to it. The design of the engine (crankcase, carb, combustion chamber, etc.) isn't like anything I've ever seen. It's extremely well built and has been running since '92 without anything more than a simple plug change and basic yearly maintenance. I'd like to know as much as possible about it. I do have the manual for it, but that doesn't give much history of this powerful machine.


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## hankster (Jan 1, 1998)

Let me see what I can find out. We have one in the shop now and I can find out what the model number is. As far as I know they were only offered by Sears for a couple of years. We do see a few come through the shop each year, most are for carb rebuilds but the one we have now needs a piston and cylinder. They are good quality engines, more commercial quality then most you will find on the market today. Problem most found with it was the weight of the thing.


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