Fuel delivery

Ok guys I have a doosey for you!

I have a 1977 Pearson with a Perkins 40HP diesel engine the current fuel line is 5/16" I want to change it to a 1/4" do you think the smaller size will effect the amout of fuel getting to the engine?

It’ll change the amount of fluid flow possible under a given pressure, but I doubt of you need a 5/16" line to feed the injectors anyway. It’s a boat motor, so it isn’t like you’ll be causing a traffic back up if Wide Open Throttle doesn;t allow you to go as fast.

What’s the purpose for changing the fuel line size?

I too wonder why you would want to change the fuel line size. A 40hp diesel engine can only provide so much power so I don’t see the boat going any faster.