How To Repair Zama Carburetor

Zama Carburetor Rebuilding
(My Experiences)

(Pictures will follow shortly)

This folio was created to demonstrate my experiences with rebuilding carburetors for pocket-size engines. Primarily 2-cycle but applies to some 4-cycle types.

First I want to quote the maxim, "an ounce of prevention is worth a pound of cure". If you keep the air filter clean and use clean fresh fuel each time, your 2-cycle engine will run properly for many years without other maintenance. Information technology's a clogged air filter and/or water contaminated gas mix that volition limit the life of your implement.

What led me to creating this page was my experience with chain saws, weed trimmers, generators, and leafage blowers. When one uses small engines from year to twelvemonth sooner or after the blasted thing won't offset. In many cases, if information technology's older than a few years 1 just tosses it and gets another. This is considering nosotros now live in a throw-away society. No ane repairs anything anymore. It's just not cost constructive. Most times information technology'due south just cheaper to simply buy a newer and more improved version of the implement. Merely sometimes the newer versions are lower quality and built cheaper because no ane repairs them anymore.

Existence recently retired, and a little more than fourth dimension on my hands I decided to practice a trivial work on a few pieces of equipment that have been tossed aside for a number of years. I don't like throwing out lacking stuff. I always try fixing things. I also have a box of pulled carburetors from chainsaws and weed trimmers that I simply didn't accept a heart to dispose of.

Offset, a flake of theory nigh how pocket-sized engines work. Small engines refer to concatenation saws, weed trimmers, edgers, leaf blowers, hedge trimmers. Virtually are 2-cycle meaning they utilise a gas mixed with oil at a xxx:1 to 50:1 ratio. About if not all use 1 of two brands of carburetors. Zama and Walbro. They all work merely virtually the same manner. Just configured a petty different from equipment to equipment. Zama has an first-class PDF of understanding, troubleshooting and repairing their carburetors. It can be downloaded here.

Most, close to 95% of the problems with these engines has to practice with not starting or only running when heavily choked. About implements are left over the wintertime with fuel still in the tank and carburetor. Virtually gas now contains 10% ethanol. Ethanol is hygroscopic. Meaning it will concenter h2o. If water is introduced into the fuel and is left in over the winter the ethanol/water will separate from the gas and collect in the bottom of the tank. If water is exposed to aluminum such as the carburetor, it will corrode and go out a white powdery residue throughout the engine. The engine may non start or you may discover that it will simply run when information technology is heavily choked. This is because the main jet is chock-full and choking the air intake has a trend to richen the fuel to make it run, or the fuel filter in the tank is clogged with contaminants.

Ethanol will also dissolve the fuel lines and gaskets in the carburetor. Contaminated fuel in the tank volition take a strong dried paint or varnish odor and the gas may take a dark chocolate-brown appearance. Trying to start the engine will draw the bad fuel into the filter and clog it upwards too. I highly recommend using ethanol free gasoline which tin be gotten well-nigh anywhere in the U.South. You just have to expect for it. Here's a website that will assist.

Most cheap weed/grass trimmers aren't worth taking to a repair shop to have fixed. Simply the labor charge could exceed the cost of ownership a new one. Some people may become a yr or two use out of a cheap trimmer earlier it quits. They throw information technology out and become a new one. Some people with a petty knowledge that want to repair their engine just purchase a new carburetor, which for the about part is easy. Just go to your small engine repair store with the model number of your equipment and a carburetor can be had for about $xxx or so. If you know the verbal model of the carburetor you can notice them on eBay for perhaps half the toll. All of them are made in China. Even the ones in high finish Stihl equipment. There are two parts to the part number of the carburetor. The first is cast in the side of the carburetor with something like C1U or C3A. There is also a number stamped elsewhere similar 53a. These numbers together brand upwards the function number for ordering a new carburetor or a rebuild kit.

The following is what I do to repair a typical carburetor. In this example a Stihl MS170 chainsaw.

(Much of what follows tin be applied to any modest engine.) I cut over xviii cords of wood a twelvemonth and use my saws nearly all year long. Rarely ane will stop working and I have to perform maintenance. Ii things usually cause bug: one) contaminated gas 2) inadequate cleaning.

Ever use fresh ethanol free gas mixed with proficient quality oil mix. I e'er stay with proper name brand oil mix and mix simply a gallon at a time. Inspect the fuel when beingness poured. It should be clear with a tinge of gilded or blue look. This is the oil condiment giving it it's color. When your fuel supply tank gets near the end, dispose of the last portion. You may accept picked up some moisture and/or debris and yous don't want anything bad getting into the fuel tank.

Periodically clean the saw of whatsoever mud and sawdust that has collected on the inside and outside of the instance. Employ high pressure air to blow out whatever drove of sawdust. Too inspect the air filter -  clean or replace. A chock-full filter can suck sawdust into the carburetor and crusade problems. I usually get a gallon of low VOC paint thinner and a small-scale brush. Cascade a portion in a small can and go over the whole exterior of the saw and get into all the piffling hiding places. And so blow everything dry out with compressed air. Soak the air filter in solvent and blow dry beingness careful non to damage information technology.

Should you decide to rebuild or repair your carburetor, do the following:

Accept a camera or use your cellphone photographic camera and take pictures of different angles the way the carburetor is mounted, the linkage, etc. Remove the carburetor. There are usually two nuts that will hold the carburetor to the engine through the air filter housing. Note: all hardware is metric. There might be other screws to remove the linkage connecting the carburetor. Call up to have pictures here too. Disassemble the carburetor noting where all screws are and the position of the ii covers. Carefully remove both covers noting the location and sequence of the gaskets. Unscrew any mixture screws. If at that place are two side-by-side, they usually have different thread sizes so you can't accidentally swap them. Remove the screw for the needle valve. Be conscientious noting the lever, spring and needle. With a small needle, remove the micro mesh filter in the carburetor. This is usually clogged. Clean thoroughly or supplant.

There might be a Welch plug tapped or glued near the needle valve bracket. Yous may not demand to remove this plug unless admittedly necessary. Remove it by puncturing it with a sharp indicate like an ice pick. Carefully remove before ultrasonic cleaning. Make certain you verify the fiddling holes are clear past bravado air through them. Past this fourth dimension information technology should be completely disassembled.

If your planning on just cleaning the carburetor make sure yous agree onto all the parts. Inspect the gaskets for rips and holes. Check the needle valve and make certain it has a proficient betoken on the end. At this bespeak I immerse the chief carburetor body and both covers in an ultrasonic cleaner and dish detergent. My cleaner has a heater so I can bring the temperature up in the tank. I usually run the cleaner for about a half hour. Once cleaned I remove the water past using compressed air from aerosol can of dust-off. Push air through all ports and orifices. Make every attempt to push air back through the tiny holes in the venturi pharynx. Brand certain you push air all around until carburetor torso is completely dry. Brand certain the throttle and choke operate smoothly. If you are using a rebuild kit employ the new parts at this fourth dimension.

Carefully reassemble starting with the Welch plug. Accept new one and place into position humped side up. Carefully tap the plug with a flat tipped punch the size of the plug. Don't tap too hard. Simply enough to cause an interference fit. Some will carefully place fingernail polish around the plug to assure it is sealed. Advisedly place the micro mesh filter into the carburetor body. Next, place the needle valve assembly making sure spring is correctly positioned (practise not overtighten whatever screws. They should be firm simply), then the mixture screw(south) (turn the spiral gently till it bottoms out and open it upwards ane-1/iv turns.) Install both covers making sure the gaskets are correctly positioned and the covers are properly positioned. Install carburetor and connect fuel line(southward). Verify last associates with your pictures.

Do the asphyxiate and throttle to make sure they operate smoothly without binding. Fill up tank with fuel mixture, set choke and give it a few pulls. It should start and run smoothly. You lot may have to suit the fuel mixture and/or throttle speed screw one time it is warmed upwards. Make sure air filter is in place and unit of measurement is warmed up earlier making adjustments.

Annotation: Some small engines may take a primer bulb to go the fuel circulating. Pushing the bulb a few times should cycle the fuel from the tank into the carburetor and the backlog returned to the tank. If fuel is cycling properly you should see it fountain up in the seedling and some bubbles in the tank. The bulb should quickly expand to its normal size immediately afterward releasing. If it stays depressed or comes upward slowly, there is a fuel restriction somewhere. Either the filter in the tank is clogged, the fuel lines accept complanate or the bank check valve(due south) in the primer department have debris in it. The carburetor will need to be removed and cleaned or rebuilt.

Copyright � 2022 Rick C. Ver 0.3 ix/20/2015

Source: https://neatcircuits.com/zama_carburetor_rebuilding.htm

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