"No problem" I figure. "For what were search engines invented?" 
. But old Earl is search-challenged enough that I couldn't find good enough info on this forum or on the Marlin-owners forum. I know the info is there, I just couldn't get to it with my limited computer abilities. But I did find that the problem is so common that it has a name: "Marlin Jam #1". And I found written reference indicating that one fellow fixed his by adding a little weld material in the appropriate place and grinding smooth, but didn't find pictures to go along with the instruction. I did mine with the old JB Weld and a little piece of steel, so finally gave in and took a Marlin apart. Fix area looks just fine after 15 (er...maybe 18 years). Took other Marlin apart, it also looks fine after a mere 15 years. Curiosity going, I took third Marlin down that has been trouble-free from the beginning. Here's how they look:
These, as you can see, are the bottom sides of 3 carriers: two upper ones with a little patch and the third that didn't need anything (areas inside yellow circle). Looking at the bottom one that always worked fine (1950 era 35 Rem.) I could see that the factory polishes the area . So I assume that they want this slick and smooth, but if they polish off .001 too much we have Marlin Jam #1. And if they get .002 too much they produce such consistent jamming that some of us lucky fellows get a bargain (like I did for my 1950 30/30 and the late 80's 35 Rem that yielded up the "patched" carriers for the photo).
Anyway, here's a side view of the fixed area -- I used a little red sharpy marking to make it show up.
And here's a top view of the fix area
In my frustrated search effort I found nice photos where a fellow did a similar thing to a Marlin 1894, which has it's own Marlin 1894 Jam #1, I gather. He used a piece of saber-saw blade with the teeth ground off and cut to length. That sounds like a good idea: next time I think I'll use something like that, or hacksaw blade. you just need a thin piece of steel about 1/4" wide and maybe 3/4" long and saw blade should be thin, strong and smooth. I think for these particular fixes I had cut out a piece from the handle of a cheapo teaspoon.
