'93 Johnson Fuel Fitting question

[Montauk_78]

I was replacing the fuel line hose in my '93 Johnson Outboard (Model# J90TLETS) and I was puzzled by the different sized fittings throughout the line. It seems like the same line has a different sized fitting on each end. First, coming from the boat side into the engine it goes from a 3/8" line to a 5/16" line that connects to the inline fuel filter under the engine cover. Then out the other side of the inline filter it is back to 3/8" up to the VRO pump connection. Out the top of the VRO pump, that fitting also is 3/8", but then the connection for it on the fuel manifold assembly that goes to the carbs is 5/16" again. Both hoses that run to the carbs from the fuel manifold assembly are also 5/16". I am just perplexed. All fittings and line are OMC original and have never been replaced, so it doesn't appear to be a mix-up by someone. I was just wondering if this is done on purpose or if there is some advantage to this change in size...or if this is an error that need correction? It seems strange to me, as you can only buy one size hose.

[clanton]

If you order the preformed hoses by OEM pn should be no problem.
Regular hose comes in many sizes.
Measure the nipple for correct size.
From engine to fuel tank, no less then 5/16 for V4.
Oil tank hose 1/4 inch thick wall.

[Montauk_78]

Thanks a bunch! That's what I needed to know!