Carburetor Cleaning & What to Use
How you clean your carburetor will depend a lot on what condition your carburetor is in.
A carburetor that has been running on your car without sitting around much will be cleaned much differently than a carburetor that has been sitting for 5 years or more.
If your carburetor has corrosion on the bottom of the bowl, then throw the carburetor away. There will also be corrosion in the passages that you cannot get out.
We at Mike's Carburetor Parts use an ultrasonic cleaner with Pro 300 as a mix, but the average person will not have access to this. Our professional cleaner had a cost of around $2,000. The cleaner Pro 300 is bought by the case for over $100.00. Some have bought one from Harbor Freight. Don't have any idea if they work as it is something I wouldn't buy, but if you do use Simple Green as the cleaner.
Take your carburetor apart. Unless there is a lot of dirt and corrosion around the choke valve and the throttle valve, I wouldn't take your carburetor down that far. It's too easy to break the screws. If you do need to remove the choke and throttle screws, grind the threaded end with a Dremmel tool until you get flush with the shaft. Carefully remove the screw with a screwdriver. If the screw stops, turn it back in and try again.
Don't forget to take a lot of digital pictures of your carburetor. Especially the rods and linkage. There will almost always be questions about how things go when putting your carburetor back together.
Simple Green - Our Top Pick
Industrial cleaner & degreaser. This product worked very well. As you will see in the video, I immersed 1/2 of a very dirty carburetor and let it soak over night. Be careful with aluminum parts as they will discolor if you soak them too long. The test carburetor came out clean and free of oil & grease. Scrubbing the parts with a brush would have helped also. Cost for this product was 11.00. This cleaner was used full strength. Directions say to mix 1 part Simple Green to 10 parts of water. Experiment with different mixtures. I would take a look at any aluminum or brass every 2 hours to make sure they are not getting damaged.
Berrymans & Gunk
Soak all your pieces (except rubber) for 4 hours. We tested all of these and 4 hours seems to be about the best time regardless of what the instructions say.
For heavy deposits of grit and grime a toothbrush may be necessary to facilitate cleaning.
Be aware that leaving your parts soaking too long can discolor the metal, especially aluminum.
Wash all parts with hot water, being sure to remove all chemicals.
Blow out all passages with compressed air paying special attention to the smaller passages. Be sure air comes out of each end of any passage. Pay special attention to the very small holes, like the idle vent holes in the venturi cluster.
Any of the cleaners out there will not do more than remove oil and grease, if that, so if your carburetor has any rust, or residue in the bowl, then bead blasting the parts will be the thing to do. Use a very fine blasting material, i.e. soda. The brass parts can be buffed with a wire wheel.
After blasting soak the parts again, wash with hot water and blow out the passages.
Super clean is a product I have used for several years to clean my parts, usually in a parts cleaner with an agitator. It's always worked great for me, so I tried it on a carburetor. Cost was 12.00, which is about the same for Berrymans and mineral spirits.
It did very well, but only at full strength.
Soaked the parts for 4 hours. Keep in mind the parts were not aluminum. Be careful with aluminum because Super Clean will discolor the metal if you leave it too long. For example, overnight would be a problem.
I also liked using Pinesol and it smells good too. Be careful with Aluminum. Pinesol will discolor the Aluminum metal if left more than a couple of hours.
Here is an idea from one of our customers. We have not tried this ourselves.
I soaked my 4100 in a 50/50 mix of Berryman's and acetone. Kept it agitated with my oxygen concentrater. Then I boiled it for one hour on a very slow rolling boil, in pinesol. With a brass brush on the Dremel, it looks like I polished it.
NOTE: The carburetor turned black when using the pinesol, but the black brushed off. I would recommend a lot less time.