Meaux,
I replied to your PM with information that at least on a Jinma (Chinese) the fuel pump does have an oil reservoir. Learn something new every day! The advice there was:
"There should be a mushroom shaped device on top, it's the vent/fill plug. Some models have a tiny dipstick. Absent a dipstick, others have a 2nd plug on the side. Remove vent/fill plug and bottom drain plug. Drain, replace bottom plug. Remove side plug. Pour in lube oil till it comes out the side. Stop pouring, replace side plug, replace vent/fill plug.
I use ISO100 compressor oil (30W). Assuming you use 15W40 engine oil, that's fine too."