It slips randomly. I assume worn or stuck pawls. But it might be a worn sprocket. It's hard to tell, since it is random. I can't trigger the failure to see if one cog slips of it its the whole body. Usually just one power stroke - enough to break stride. And then will behave for a while.

I'll have to try flushing it. I have a sonicator here, so if I can find the removal tool I take it off and flush it out. WD-40 flushing will have to wait until it gets a little warmer (Wind chills are in the range of -5°F!)

If that doesn't work, I'll deal with it later.

Worn cogs are not random, the chain will jump like clock work....

Very cold temperatures will affect pawl perforfance as the internal lubricants (or lack thereof) lose viscosity....

You can flush it on the wheel, lean the wheel at an angle, stuff a rag or paper towels between it and the spokes and flush away. The rag will soak up everything coming out of the back.

My LBS wouldn't even look at it. I'm not very happy with them. I was in there a while back looking at options, and all they wanted to do was sell me a Specialized bike. I told them that I wasn't interested in Specialized, and just wanted them to show me some of the other makes they carried, but it was right back to Specialized... which I didn't want... So they showed me a Specialized...
When I called about the free wheel, they refused to even look at it. I followed up with a question about pedals. The mentioned Look, Shimano, and Speedplay... and proceeded to give me the hard sell on Speed play. I mentioned that they failed to iinclude Time, Mavic, and Campy pedals... and went right back to trying to sell me Speedplay, even after I stated that I wasn't interested in Speedplay. <rolls eyes>
And I thought I was stubborn with brand loyalty. At least I'm not supposedly trying to provide a potential customer with what is best for them. I'd rather do my own research and buy on-line than from the LBS and deal with them trying to tell me what they think I want. [end LBS Rant]

~Monkey~

Actually, I thought it may have been a cog slipping on the free wheel body. Note sure if this is a typical failure route or not. The teeth look good, just a bit "aged".
I need to pull it anyways. I want to clean the hub, and it's easier with out the free wheel. I used to do this regularly, swapping the free wheel between wheels. I had one of those UNI wheel covers back in the day, and had to pull it to install or remove the cover. And the sonicator will do a better job of cleaning it anyways.

~Monkey~

Bikeville in Philly. Go there. Be courteous and you should get the attention you desire. They probably have what you need NOS, in my experience it will be priced by its rarity and your attitude. Their upstairs has a museum worth of stuff.
I think the freewheel problem is a worn cog or two. Those alloy mechanisms were designed for Special Use, not for everyday. Think time trials only.
That is how we viewed them way back.
A worn cog will show for example by; when it works in the workstand but not under load. Keep track as to what cogs it skips in. Another chance is to check for chain stretch. If you are lucky the chain has stretched and the cogs are okay. If you have a new chain and there are no stiff links, you are back to the freewheel. There are a few members here who have much experience working on freewheels, (I don't have the patience) trouble is that if a spring or pawl is needed it must come from a donor mechanism, there are two pawls, chance of having both fail is low.

Campagnolo was the only maker who made spare internal parts of that type back in the day, as DD advises, terrific units, strong alloyed cogs, you pay the Campagnolo price. Good luck finding spare internal parts though, the guys who bought the service chests keep them for themselves, and quite understandably, they fetch a handsome sum. Cogs do show up from time to time though, rarely for the other brands. If you find one, you need the special puller or you will damage the body, period.

Everest was standard equipment on Masi (both venues) for a long time in the 70's through the 80's. We considered them more consistent than Regina in quality.

If I learned one thing from this thread it's that the original idea of a "gruppo" was more about group pricing, than about a coordinated designed set of parts. So a gruppo could be a mix of parts that as a group are discount priced for less than the sum of their individual prices. Understood this way, all the confusion about what constitutes a "Super Record Gruppo" kinda melts away. Is this more like the original meaning?

Parts were sold a la carte with few exceptions. Cyclo-pedia one of the original mail order shops where one had to send payment in advance. They did advertise special group pricing in their catalog, but generally in standard sizes, say 170 mm cranks, 52/42, English threads. Bikecology also sold groups mailorder, similar pricing schemes, and started advertising prices... to the consternation of others. The whole group pricing marketing came in the 80's where more shops jumped on the mail-order wagon, some producing pretty comprehensive catalogs with detailed specifications, like Palo Alto Bike Shop and others. I have one catalog, I have to dig out, from a shop up in Northern California, a terrific resource. Like the old Spyglass catalog was for sailboat hardware in the 70's.

When the web took hold, things really ramped up, now they promote "build kits" too.

I do agree in this regard that there was a vacuum regarding the description of Campagnolo group names, shops filled the void, and some bicycle brands used the shorthand too, much easier for the consumer to comprehend. Reasonably accurate.
Sometimes there were alternate descriptions, like Super Record Reduced, or Super Record Steel, "Super Record" with steel spindles in the bottom bracket and pedals.