Fuel Pump Plumbing Tutorial
I have read many words regarding this basic task. Some folks know the correct way to accomplish it, and some folks are way off base.
The method that I use is time honoured and well proven.
Safety is a prime concern.
Leaks are the bane of a fuel system...an air leak on the suction side can turn your jet into a glider, and a fuel leak under pressure can turn your jet into a fflying fireball.
I have seen one jet go up in flames during flight from a pressure leak. The result is not pretty.
Another thought...Festo or other brands of "push in" fittings are very convienient...but they are not the best thing on the suction side of the fuel system, in other words, don't use them upstream of the pump. If used on the suction side, any bends in the tubing runs should be of maximum bend radius; sharp bends into a Festo type fitting increase the chances of an air leak.
In order to make a leak proof fuel pump installation, some easy steps must be accomplished.
We will be using polyurethane tubing for this job in both 4mm, and 6mm OD.
First, cut one end of the the 4mm tubing making sure that it is square. No angled cuts allowed. I use a tubing cutter for this job. I used transparent red colored 4mm tubing so it would be more visible in these photographs.
Apply a small amount of Vaseline to the pump fitting, then heat the cut end of the 4mm tubing with a heat gun to soften it. Push the 4mm OD tubing onto the fitting, making sure to bottom it out.
Cut it off flush with the end of the barbed fitting with a sharp razor blade.
Cut the 6mm OD tubing square with the tubing cutter.
Telescope the 6mm OD tubing over the 4mm tubing on the pump inlet fitting, and using .020 Stainless Steel safety wire, double wrap the wire around the tubing, and twist, being sure to pull the wire tight enough to visibly indent the 6mm tubing.
Cut the wire and bend the end over so the sharp end cannot snag fingers, wires etc.
Add the pressure line to the pump using the same method dscribed earlier foer the pump feed line.
This entire operation only takes a few minutes to perform, and will deliver leak-free service for the life of the installation.
Any questions, or clarification required?? I'll be happy to help...