Originally Posted by a64pilot
I would suspect air in the fuel
lines, unless of course it's idling lower than spec, but I still bet air.
You need to find someone to show you how to change your own filters, drain water
from the pre-filter and bleed air from the system, it's a skill you will need to have as eventually you will be faced with having to do it without a mechanic
A very slight leak will introduce air in the fuel
line, especially if it's been sitting and it will be hard to start or keep running. Get someone to teach you how to bleed the lines, change the filter, etc. Check all of the hoses for chafing, leaks
(it's a suction system unless you've installed a lift
pump at the fuel tank
, so leaks
might not show up as diesel
in the bilge) loose hose clamps, etc.