TOPIC: fuel line diameter 70 tripple

What diameter is the fuel line supposed to be between the fuel pump and the fuel inlet? I went to replace the line measured the fuel pump inlet and got 3/8 inch brought it home and it fit fine on the fuel pump but was too big on the inlet. was this hose special with 5/16 on one end and 3/8 on the other. The line I took off is hard as a rock but looks like it may have been stretched over the fuel pump inlet.
Could the inlet have been swapped with a smaller size?

All right I bought a 5/16 fuel line forcing it over the 3/8 fitting on the filter fitting on the fuel pump. I have a big concern over the sharp turn coming off the fuel filter.
here is a pic. of the old hose and what happened to it.
Here is a pic showing why the sharp turn is necessary. It has to stay inside the upper cowling. I made the hose a little long to help with the turn.

While I'm not familiar with the triples, some of the OMC V-4's have a supply hose configured like you are describing. One end is a different diameter than the other. Some are still available through BRP (OMC), and the supply houses (marineengine.com, boats.net, etc.) but very pricey IMHO.

I did the same thing you did, made the best I could with what was available to work with. Looks like your loop will prevent the sharp turn, should work out okay?

Mark's right, that should be fine. Too late now but I was going to suggest using a heat gun to warm up the smaller hose a little then slide it on. Just don't get them too hot. It's soft rubber but it will still expand a little when heated up.

Bob

Bob I stuck it in boiling water to soften it up first. I am going to attempt to mold a hose using a piece of copper line and boiling water. Clamping the line to the tube until it cools off. I have done it with a heat gun but it is very tricky. I get impatient and destroy the hose.

Yeah you definitely have to take your time with the heat gun. Sounds like you have a good plan.

Bob

I use Honda motorcycle fuel line. It isn't reinforced, so it has a slim profile like the old stuff from the 50s, 60s, and 70s. Very high quality rubber, supple, and resists kinking. It is designed for today's lousy alcohol laden fuel. It can be purchased by the foot. I don't have the part number on hand, but you can probably figure it out. You can get it in a diameter to fit the smaller end, and it will stretch to fit the larger end without splitting. Use a dab of dish soap on the fittings to help 'em go on. The reinforced stuff they sell at auto shops sucks for under hood outboard motor applications, and it isn't necessary for safety.