Brains and meninges were crushed using a 3 mL syringe plunger then homogenized by repeated passage through an 18 - gauge needle. (journals.plos.org)
Cumulus - oocyte complexes (COCs) were aspirated from 2 to 5 mm follicles with PBS (containing 5 % FCS) by using a 5 ml syringe fitted with a 20 - gauge needle. (journals.plos.org)
After posting my question here and since my feeling was that the problem seems to be related to some air bubbles in the fuel system, I've decided to take out the fuel filter, drain all the diesel fuel, fill it manually (by using 10 ml syringe since I hadn't a manual pump) with diesel and mount it back. (mechanics.stackexchange.com)