Oil line sizes

[Jeffspx]

Got a 94 SPI for cheap with stripped rotary valve. New motor is here, going through the entire ski before everything is put back together. Got 3/32 tygon for the injection lines. Seemed that everyone was using 1/2inch for the RV feed and return and 5/16 for the pump feed.
Got some 1/2 inch ID tygon lines and they dont fit tight on the RV engine fittings. Is everyone just cinching them down with clamps? Is 1/2 inch supposed to be the outter diameter?

Thanks very much.

 

[mikidymac]

Yes, they are actually metric, 12mm for the oil bath and it is 8mm for the pump.

12mm = .47" so 1/2" is a little bigger.
8mm = .315" = 5/16"