it might be a water hose
if there is a plate that hose goes to with one hose in and one hose out(one looked as if it was in a T fitting off the block and the other a T fitting to the bypass) then it may be a heaterblock.
I have seen those on some older lifts. While looking at the diagram i couldnt determine for sure but it did seem that there were some hoses that looked like they ran from the block or intake over to the carb but it didnt show the picture very well.
A very crude drawing unfortunatly
And its been a few years since i've even layed eyes on one close enough to remember they layout.