I would like to know if most builders are running the 750 fuel hoses inside the channels as called for in the plans or are they keeping them outside for easy servicing?  I also don't see how you can run them under the seat base and have enough room?  I looks like you could route them along the pilot side part of the way back and then have to make a loop to go up and over the gear channel and then back?

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I ran mine down the inside of the rear fuselage uprights (one on each side) then over to the central control tunnel, up the left and right sides of the floor of the tunnel to a console with Andair selector valve, then a single line to the firewall. The only interruptions/joints/connections are at the top of the upright where the wing will join, the fuel selector valve, and the firewall, so all fittings are accessible after construction. I used Earl's Teflon-lined, AN6 braided stainless lines, so I "hope" there will be no servicing or replacement necessary in the future. As a further precaution (although those lines are tough!), everything is secured with padded Adel clamps and all edges where lines go through holes or around corners are grommeted or have soft edge trim, too.

The Andair selector gives me "left, right, both, and off" - I much prefer this to permanently inter-connected tanks. That way, if you got some really bad contamination in one tank, you can isolate it and run on the other tank.



Hi John, im glad Ed brought this up, I am in the process of planning my fuel routing also. John, do you have any pics of your fuel lines going through the tunnel? I don't have any controls yet, so I'm not sure on what will clear later if I mount my lines. John, I might need to make another trip down and see yours again soon!
Thanks, John.  I will look for the Andair selector.  As Steve says, if you took any pictures, we'd love to see them?

I've not really got a good shot of the line in the tunnel where you can actually orient it and make sense of it! However, it's pretty simple, just run the lines up the left and right sides of the tunnel right above the floor. I used 2 Adel clamps bolted together to make a "butterfly" at each clamping point along the wall of the tunnel - Ran the fuel line in the lower clamp and the brake line in the upper clamp. That way, they're tucked down well away from the control rods and the cables - no possibility of interference at all. I exited in the bottom corners of the tunnel through the front support and then swept the fuel lines up to the back of the console and the Andair valve.


I did some more digging in my photo files ... no good pic of the line in the tunnel, but I've got everything else!

Here's the line entering the upright ... it's loose until the hole location for the  tank line is determined, then the bulkhead fitting will be affixed to the sidewall:


 Here's the line "rounding the corner" entering the tunnel. I "butterflied" 2 Adel's - one for brake and one for fuel - and put this one right on the corner ... no possibility of lines chafing on the corner:

Here's a "butterfly" in the tunnel, but the fuel line has not been placed in the lower clamp yet. It's bolted to the sidewall near the bottom of the tunnel:

The lines sweeping up to the back of the fuel valve:

And the single line from the valve to the firewall - use a steel fitting here  because the gascolator mount/firewall passthrough is stainless steel:


Thanks so much for the great pictures.  This really gives me a good picture of your system.  Any issues installing the braided hoses?


No big problems ... Earl's (ANplumbing.com) has online videos to show you how to install the fittings - just be sure you get the correct hose and fittings - I used Speed-Flex hose which uses Speed-Seal fittings. Watch your bend radii - I think it's about 4". One catch is that although the fittings are easy to install on the bench with a vise, you can't thread them through all the holes with the fittings installed, so you have to install the line fittings for the fuel selector valve AFTER threading the line in place (unless you wanted to use enormous holes and grommets! HAHA!). It's certainly do-able, but a little more trouble to install the fitting on the line inside the plane - it went a lot easier than I anticipated.

It's probably ove-kill, but I also pushed plastic split-loom over the stainless line in the upright. My thinking was it would reduce any chance of vibration causing chafing - of course the stainless would probably eat through the aluminum and not vice-versa, but it made me feel better about running a line where I can't see it. The line is stiff enough, and with all the other stuff crammed in the upright, I don't think there will be any vibration going on, anyway.

The biggest issue is expense - you'll probably drop $250 or more on the lines and fittings, and the valve isn't cheap, either (but much cheaper when bought as an "AirVenture Special"!). DON"T buy cheapo Chinese lines on Ebay - I looked at them and they have a WHITE Teflon liner, which means it is not carbon-impregnated. The "good stuff" has carbon (obviously making the liner black!) to make them conductive and eliminate any static electricity issues. Earl's has it and of course AeroQuip has them. I went with Earl's - if it'll take the stuff they run through top-fuel dragsters, it'll take anything that comes out of a FBO's pump! LOL!



As always, thanks for a great response.  I'll be calling ANplumbing.com after I figure what I need.  I was not really excited about the hose that Zenith supplied.



Where did you install your gascolator? 


That last photo in the series above terminates in a stainless firewall bulkhead/gascolator mount (from Spruce). The gascolator screws directly onto the bulkhead fitting:

I placed the mount as low on the firewall as I could without cutting into the stiffener on the cabin side. The gascolator hangs down below the belly of the plane so it is at a low point and allows easy access to the drain.

Remember to allow clearance for your engine mount! I cut it a little too close and had to grind down the top right corner a few mm to give adequate clearance - fortunately, there's plenty of excess metal there!


I have my gascolator at the same position as yours.My concern is, the lowest point of the fuel system is between the baggage floor and the front seat support. Been thinking of installing a sump drain valve somewhere along there as some others have done, or putting the gascolator back where the plans show. I did not like the idea of the gascolator hanging out under the fuse exposed, but it is the lowest point. I don't know if the gascolator can purge water from the fuel effectively when it's not at the low point. 


I researched gascolators and there appears to be three dominant opinions:

(1) The gascolator MUST be at the lowest point in the system.

(2) It doesn't matter where you mount the gascolator - the screen is so fine it filters out water anyway and works anywhere you put it.

(3) You don't need a gascolator at all - just use an inline fuel filter.

I honestly believe my gascolator is at the lowest point in the system - the hoses run over the gear channel and stay more-or-less parallel to the control tunnel floor, then up to the fuel selector and down to the firewall. If it's not the lowest point, it's mightly close! I had my friend (who's an A&P and occasionally helps me) and also had an A&P IA look at the installation and they said it was fine!

I feel the gascolator is more protected in this location than hanging under the belly! Think about it - there's a lip on the cowl which projects down to about the same level to shield it, and, if off-field you hit a bush or something - it has to go through the propeller first (if it's still turning!) before it gets to the gascolator. I like the idea of having as many connections as possible outside of the cabin area in case of a leak.



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