I've got the 2620 - I don't recall seeing the extra cap, just the one on the rocker cover but it is a slightly different engine I guess. That's where I filled mine. What the heck is that other cap for? it's got to be the engine oil as well. I don't think I have that on the 26 hp. Wait for somebody with the 29 to answer and remember - don't panic - stay calm, you will figure it out.