Hmm... interesting: according to this Cartoon Research article, Margaret Kerry stated that Emil never partook in a CLUTCH CARGO recording session, and that he started working for Cambria after the series completed production. As for the episode you posted, U.S., I can hear some similarity vocal-wise with the "Shark" character, but I don't quite think it's Emil. I can't quite pinpoint the exact difference (perhaps a bit higher pitched), but I think it's someone else.
EmilSitka.com mentions Emil worked on at least two episodes of CAPTAIN FATHOM (here and here), another Cambria Syncro-Vox show. Perhaps Emil misremembered that gig as being CLUTCH CARGO?
Yeah, I’ve seen that article and that’s why I was always hesitant to post about this, as Kerry would know given her husband owned Cambria. That being said, I also went back to the source of Sitka’s interview (the book, “The Golden Age of Chicago Children’s Television”) and it turns out I misremembered what Sitka said; Sitka just claimed to have worked for Cambria’s Synchro-Vox shows, he didn’t mention CLUTCH CARGO specifically. So for that, I apologize; there’s no official source confirming Sitka worked on CARGO.
That being said, there are multiple cartoons with that Sitka sounding voice, and it is possible too that Sitka came in during post-production, which would explain why Kerry wouldn’t have remembered working with him. However, I don’t want to spread any misinformation, so I think you’re correct, it’s not Emil on CLUTCH CARGO.