87 40ETLH precision blend oil line-why 2 sections of oil line?

[Bullbream]

Hello, I'm replacing some of the old clear oil view lines on my 40ETLH where they go into the intake behind the carbs. I noticed there is a plastic union/joint with a lower line that goes to the pump, The lower lines have been painted with the same paint as the motor. Both sections of line seem to be the same I.D. and the union does not seem to have any difference in I.D. on either end or a check valve in it. When I ordered the replacement clear line for the 3 lines I received enough length to replace these painted sections and the clear section with one length of line without any joint/union and this seems like a better idea to avoid future leaks. Is there a purpose to these 2 sections of lines for each cylinder other than cost savings on yamaha's part (maybe clear line is more expensive and this let them use less)?

Thanks for the help!

[boscoe99]

Where in this illustration is the T?

[boscoe99]

I typed T. Should have been union.

[boscoe99]

Have you owned the motor since new? Backyardigans are known to make some bewildering modifications to their motors.

[99yam40]

I thought I read before that the old motors used an inline check valve in the oil lines, newer had the check valves in the oil pump

[Bullbream]

The 33s are the clear lines, 34 is union/tee, 6,7 are the black /painted lines in pic. I bought the boat/motor from 2nd owner since 80s. It appears to me nothings been touched except carbs were R/R recently…I did put on a clear length of temporary oil line til I received official Yamaha part…I looked up parts for some of newer bigger precision blend units and they have a check valve installed in that spot where my union is. This makes sense to me-as I can view my oil running back at times leaving air gap/bubble that I don’t like to see…

[Bullbream]

Here is another view of system if it helps…

Thanks!

[DennisG01]

Probably because someone had already replaced the original hose (painted when the engine was painted) with newer hose?