Success!!
I did a small test batch this evening. The "recipe" on the bag of Masonry Cement calls for 2.25 to 3 parts sand to one part Masonry Cement for Type S Mortar (called for by code for a building foundation wall). That's what I was mixing it at.
So tonight I doubled it to 2.5 parts sand to 2 parts Masonry Cement and it stuck on the vertical joints real nice.
Now, at that ratio it's probably not technically "Type S" any more - but I doubt the inspector has a way of telling anyway - any the part of the wall I'm doing now will be buried over 2 feet deep the next time he inspects....
Anyway, the next time I mix a batch, I'll back it down to 2.5 parts sand to 1.5 parts Masonry Cement and see if it still sticks...
Thanks for the help, guys.
WVBill