Carb parts fresh from a 'sonic bath I've recently been working to clear my backlog of carburetors in need of rebuilding, consisting of five sets of Gen-3 carbs. It's always a bit like unwrapping a gift when I begin disassembly of a dirty set, never knowing what I might find lying in wait. Clogged jets and petrified gaskets are expected, but there's also broken bits, incorrect parts and creative assembly from past attempts by well-meaning DIYers. Here's a sampling of typical chores.
(Below) These carbs' vacuum diaphragms are afflicted with some sort of white and green stuff, possibly mold or mildew? These slide assemblies are NLA so I treat them with a delicate touch. Here I'm using Zep degreaser, a mild cleaner, massaging the rubber diaphragm with finger pressure and a soft toothbrush around the edges. In extreme cases the round rubber edge can be coated with stubborn crusty corrosion from a rusted diaphragm cap — a challenge to remove without damaging the diaphragm. I use a warm soapy bath and a fingernail to gently scrape the crust off as best I can. If the rubber seems particularly dry I will rub on a thin application of red rubber grease to rejuvenate and preserve the rubber. I also clean the plastic slide by scrubbing with a non-scuff kitchen pad followed by a hot water rinse and air dry.
(Below) These carbs' vacuum diaphragms are afflicted with some sort of white and green stuff, possibly mold or mildew? These slide assemblies are NLA so I treat them with a delicate touch. Here I'm using Zep degreaser, a mild cleaner, massaging the rubber diaphragm with finger pressure and a soft toothbrush around the edges. In extreme cases the round rubber edge can be coated with stubborn crusty corrosion from a rusted diaphragm cap — a challenge to remove without damaging the diaphragm. I use a warm soapy bath and a fingernail to gently scrape the crust off as best I can. If the rubber seems particularly dry I will rub on a thin application of red rubber grease to rejuvenate and preserve the rubber. I also clean the plastic slide by scrubbing with a non-scuff kitchen pad followed by a hot water rinse and air dry.
(Below) The main jet needles are often stained with sticky brown varnished gasoline. This I remove with a scrub pad and degreaser or solvent. Two of these four float hinge pins were very difficult to remove due to varnished gas. Here, I'm using 1200-grit paper wetted with Ballistol to cut the varnish, allowing the floats to pivot freely. I like to roll these items (and the pilot adjustment screws) on a flat surface to check for straightness.
(Below) I'm no longer able to source individual float valves for the Gen-3 carburetors, so I rely on Keyster rebuild kits, which are quality Japanese-made parts. Next, this particular carb set had a broken enriching (choke) valve — these are soft brass and don't like to be forced. I learned this long ago when trying to remove a stuck valve by pulling with pliers. It didn't take much force to pop that little head right off, like the one shown here. This one had a bent tip which expectedly broke when straightened. Note that there's two distinct parts here…one has a wider gap to allow room for two pieces of linkage on carbs number 2 & 3 (red arrows). I clean these shafts with 1200-grit sandpaper wetted with cleaner/lube, like WD40 or similar. Shown next is an air cut valve assembly. These are often reusable, like this one, if treated gently. I carefully clean the rubber diaphragm and apply a light film of red rubber grease to preserve it. These assemblies should be removed when performing a thorough carb cleaning.
(Below) Here's two shots of the various parts cleaned and ready for assembly. The pink arrow shows how I mark each carbs' float with permanent marker dots. This way they maintain what float level adjustment they had previously, saving time setting the float heights after installing. I also keep the slide assemblies with their original carbs — not necessary, but my thinking is that each is well mated to their carb, so may as well keep them paired.
And here's a few more examples of what may be lurking in your carb project.
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