I'm in the midst of rebuilding a few sets of VFR carburetors and at least one set has languished far too long in old degraded gasoline. The result is a sticky varnished mess, clogging passages and gluing various parts to one another.
Case in point; this needle and slide. The needle itself looks as if it's sat at the bottom of a swamp for a few decades but the plastic slide is also covered in gooey varnish. All this needs to be completely removed if this part is to ever effectively meter fuel again.
It would be nice if the ultrasonic cleaner would magically make this badness go away, but no such luck. This requires careful hand cleaning. I like to use a product called Ballistol, a multi-purpose cleaner and preservative. I gently rub the affected areas with a patch of kitchen non-scratch pad as the varnish slowly dissolves. In the second photo below I'm using the reflected light to see that there's still some stubborn varnish on the slide. A little more effort and everything's back to normal.
NOTE: Upon disassembly, three of the four slides in this set were stuck in their bores along with three immovable butterfly valves. I've had good luck freeing these items by soaking overnight in a tub of hot water and soap solution — in this case I used Simple Green. Forcing the plastic slides will often crack the plastic so patience pays off.
Case in point; this needle and slide. The needle itself looks as if it's sat at the bottom of a swamp for a few decades but the plastic slide is also covered in gooey varnish. All this needs to be completely removed if this part is to ever effectively meter fuel again.
It would be nice if the ultrasonic cleaner would magically make this badness go away, but no such luck. This requires careful hand cleaning. I like to use a product called Ballistol, a multi-purpose cleaner and preservative. I gently rub the affected areas with a patch of kitchen non-scratch pad as the varnish slowly dissolves. In the second photo below I'm using the reflected light to see that there's still some stubborn varnish on the slide. A little more effort and everything's back to normal.
NOTE: Upon disassembly, three of the four slides in this set were stuck in their bores along with three immovable butterfly valves. I've had good luck freeing these items by soaking overnight in a tub of hot water and soap solution — in this case I used Simple Green. Forcing the plastic slides will often crack the plastic so patience pays off.
(Below) Next I'll deal with the float bowls, where the drain passages have filled with a sticky black residue from evaporated fuel. I begin by removing the drain screw and scraping the crud out. I polish the drain screw tips with a fine sandpaper then let everything buzz away in the ultrasonic cleaner. Little by little these carbs parts are brought back to service, pictured below with a fresh set of VITON bowl gaskets.
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