Hi, So after reading where a guy used a torch to heat his carb and then dropping into water to loosen up the rust I got to thinking about how the engine rebuilders remove rust and scale from the cooling system. Then heat the block to something like 400 degrees for an hour. I may have the temp off but is seams like a good way to free up the rust inside a carb. So am I on the right track? Thanks, Scott
To my thinking, it seems like a good way to horribly crack a carburetor casting.
Not a good idea! Carbs are made of soft metals, brass, aluminum & cast. I would only dip it in carburetor cleaner after you remove all pieces. Never dip the float, seals or gaskets as they will absorb the cleaner and become useless. Use air to blow it off.
Depends on the carb. With a cast iron body like the later G or the NH, some heat shouldn't hurt it. In fact I've removed stubborn float valve seats and spray nozzles from NH carburetors by turning the body red. Many times those parts are stuck so fast that even with the right tools they don't want to budge. Maybe I was just lucky, but it didn't do any damage.
I just heated four L-4s today to get apart. Two were iron and two were brass. Heat the area you are working on and then dunk in cold water.
I use heat but I'm to lazy to go get the water,so I usually just allow them to cool naturally .It works,and gives me time to be doing something else.
Brandon, The water cold or hot scares me. But I think a cast iron carb heated for an hour and then set aside to cool should work. Even a reheat if needed. I think thats how they do engine blocks. Thanks everyone for the input, Scott
Scott, Im probably the one you are referring to. I have done aprox 20 carbs with the heat/water method thru the years. So far, not a broken carb. But I want to say right off the bat that I am not recommending it to anyone. While it has always worked for me, if you are the least bit afraid of doing it "Don't" The other thing is heat/water is only for cast iron carbs. Brass carbs can be heated but you should let them cool on their own. Do not use torch heat at all on aluminum. I also have only rebuilt NH carbs with my heat/water method. I remove all the throttle and choke plates and shafts. I also remove the name tag. I usually do not try to remove the needle seats. They will come out very easily later. Then I slowly heat the carb to a dull red. Do it in a darker room and not in the bright sunlight. It is easy to see the dull red in a darker/shaded place and not over heat the carb. Then I let the carb cool till the dull red is gone. and then throw it in a bucket of water. The "shock" will loosen any and all rust. It also will melt out the lead plugs in the small passage ways. That will let you run a small drill bit into the passages and clean them very well of the loose rust. Always run the drill bits by hand, and never use a power drill. You are just wanting to remove the loose scale, not any metal. Each passage is a two diameter hole. There is the larger outside end that is where the " passage plug" was and the smaller passages the gas passes thru. Be careful not to lose the "ledge" in the bottom of the plug end of the passage. I use 1/8 inch brazing rod to make new plugs. I make short plugs of the brazing rods to stand about 1/8 inch "proud" of the casting. Then I take a very small tack hammer and slowly "peen" the brazing rod to "swell" it into the hole and form a small rivet head. There are nay-sayers who will scream Oh My and lose sleep at night with fears of what Im doing. But it has worked for me, but there are no guarentees, not for the weak of heart, and your mileage may vary... Submitted with respect, Donnie Brown ...
What Donnie said, except I use Stan's trick of installing 8-32 Allen set screws instead of plugs. They can easily be removed and replaced for cleaning. I also put the tag on with screws for the same reason.