Thanks for all the comments everyone. It's cold now but I'll look into lubrication and also the Bussmann "cb221-30" circuit breaker which I believe is the correct type for my regular size fuse.
It is hard to answer if the fuse only blows going up as it has happened after lowering the tongue but was it blown after lowering fully to the end of travel or after attempting to start to raise the tongue? I'm not sure. I can do some testing to find out but at this point I think the jack will get lubed, breaker installed and that will be it.