One of the reasons I didn't fly my plane when I forst bought it was because the fuel system was an in flight bonfire waiting to happen.  The person I bought it from luckilly never got it running to find out.  It turned out to just be some crud keeping the float in the carb stuck, but there were a lot of more serious problems.  The original fuel tank had ten gallons in the main tank with another four gallons another internal tank at the top to give more fuel pressure for a Posa carb that was fitted at one time.  There was a transfer pump to transfer fuel from the main tank to the smaller tank and three float switches in the upper tank lighting LEDs on the instrument panel for the upper tank fuel gauge.  The plumbing was a nightmare.   There was a vent line, a line from the tank to the inlet of the transfer pump, a line from the outlet of the transfer pump, a line from the ten gallon tank to the instrument mounted fuel selector, line from the four gallon tank to the fuel selector, a line from the outlet of the fuel selector through the back of the fuel tank then through the front of the tank and through the firewall and two lines from the tank from to the top and bottom of the instrument panel sight gauge.  That is a total of nine aluminum fuel lines entering and exiting the tank and every one had a rubber hose with a hose clamp on it.  I cut them all out and joined the four gallon tank to the ten gallon tank.   Now I have a vent line, an inlet from the transfer pump from the new wing tanks, and one outlet at the bottom.  All lines use flared AN fittings.

This picture shows the new Zenith carburetor I installed.  The brass shaft off the bottom is for the mixture adjustment.  It is out of a Dremmel flex shaft.  The tube it goes into is a heavy wall aluminum tobe with a nylaflow tube inside it.  You can see the new ACS gascolator behind the carb.

Here is another view of the flex shaft and the attachment to the mixture control on the carb.  The end on the flex shaft was made out of stainless on my lathe.  The hole in the side of the carb is where the choke shaft used to be.  I removed the choke and added a primer system.  The hole has since been plugged.

This picture is the guide tube and support for the mixture control.

This is my part of my mixture control.  It takes about three turns on the mixture screw to adjust the mixture fully.  Some people use a throttle cable and a knob on the instrument panel that turns to adjust the mixture.  I wanted a regualr vernier mixture knob so I could make fine adjustments and so I could just shove in the knob for full mixture when I needed to instead of fiddling with turning a knob and trying to remember how many turns I needed.  The gear rack here connects to the mixture control and turns a pinnion gear that is connected to the shaft that turns the flex shaft on the other side of the firewall.  The hole thing was made on my milling machine and looking back I shoud have probably just bought a revflow carb.  Live and learn.

Here is my mixture control and throttle.  The carb heat control is between them.  The angled spacers were done on the lathe and milling machine to angle the shafts so they didn't hit the corner of the fuel tank.  One of those "oops, it doesn't fit"s.

Here is the modified cowling.  I had to add a bump on the bottom to give me clearence for the new carb and the relocated oil cooler.  The upper hole is the oil cooler air inlet.

Here is the air filter I made.  It screws to the cowl behind the small round hole.  The filter element is from a waterproof K&N air filter.   I has since been siliconed in the fiberglass piece around the sides.  When it gets too old to keep washing it I will pull it out and silicone in a new one.

Here is the bottom of the fuel tank.  You can see the Westach capacitive fuel sender.  This is a very good fuel indicator system and the people at Westach are great to deal with.  The fuel outlet is an aluminum welding flange that is floxed inside the tank.  I bought a finger strainer to screw in the pipe thread on the flange , but it brought the fuel valve too low so I counterbored the hole in the 90 degree brass fitting and took the screen out of the finger strainer and soldered it into the 90 degree fitting to give me a low profile 90 degree finger strainer.  You can also see the routing of the fuel line and the mixture control.

The fuel shutoff is very simple, on or off.  It is in the off position now and it is nearly impossible to accidently turn it off with your knee.

Here is one of the primer lines.  I can't stand a choke on an airplane.  The sqare blocks were welded on one intake manifold on each side.

The new intake manifolds came from Great Plains.  I had to shorten things as much as I could to fit in the updraft carb and not have the bottom of the cowl extend down an extra foot.  The flange was cut off and welded about an inch higher than stock.  The hose clamp holds on the clamp for the throttle cable.

This portion of the intake manifold was also cut off and welded shorter.

Here is the cabin heat box.  I still need to build a heat muff.   The Aeroquip flexible line with the fire braid around it between the carb and the gascolator is the only fuel line that is not aluminum tube.  Yes, I am fuel and fire paranoid.  The 1/8" line from the top of the gascolator is the inlet to the primer.  The ACS gascolator has a screen it so I don't have another fuel filter.

Another view.

This fuel selector selects which wing tank fuel is transfered to the header tank from.  I made an extension to put the selector on the front of the spar.   You can selector in the off position straight up.