As long as the diameter of the supply line is sufficient to get enough fuel to the engine at full throttle, then it should be fine. If you haven't had any trouble with the engine acting like it was fuel starved, I wouldn't worry about it. However, if the fuel hose(s) are more than a few years old, I would replace them with some of the new ultra-low permeability hose. The standards have been updated recently, and the new stuff is much better.
The return line should be the same diameter as the supply line. The vent line for the tank is usually a bit larger.
03-03-2011 05:49 PM
Down to working on the engine in our 31. Last year we used 7 gallons of fuel and the year before we used 5 gallons. That means that more than half of the fuel in the tank is 3 years old, so I took the fuel line loose from the engine and put it to the return line and ran the pump until the filter clogged up and again and again until the filters don't clog up. ( actually took 5 filters )... now to my question... part of my fuel line is 1/4 inch and part is 3/8.. does anyone know what the size should be used?