Gravity feed fuel supply

[troubles]

What is the min. pipe size and decline needed to get the fuel from a above ground tank to boiler 100 ft" away on a two line fuel supply system with 4 boilers?
This system has been in use for aprox. 15 years. and now with a new water heater replacment the third boiler whitch is the smalest is fuel starved.

 

[jsummerfield]

Data please. A small airplane uses tubing between the wing tanks and the engine. What size boiler, what fuel, etc. What is the size that appears to be too small? How many bends and other piping fittings? Is there a strainer? Do you have a Crane book? ...

John