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 agree that there's a second low point (actually two additional since I have independent lines from each tank), but I think of a gascolator as mostly an effective filter that also gives me a sample for color, odor, and lastly, detection of water.

Think of this scenario - you get fueled somewhere and as it turns out, the very last gallon you pump is heavily contaminated with water, and you happen to park on a slight incline with the affected wing/tank pointed downhill. Next day, you dutifully sump your tanks and check your gascolator/gascolators - all clear. Where's the water? In the low end of the tank! After taxi and about the time you rotate, THEN is when that slug of water comes down the line!

Unlikely, sure, but possible. Now personally, my present plane is 100% hangared, fuel is double-filtered and stored above ground and under cover, and I have had zero problems in 20+ years/2500 hrs, so I can probably be a little more relaxed about the gascolator, If I was either a camper or third-world flyer, I'd probably have more gascolators. I guess we each have to analyze our personal situation. I did, however, get an A&P and an A&P AI to check out my system and they both thought it was fine.



Has anyone found a fuel selector valve with "left, right, both, and off" that has a flow divider return line when using  a fuel injected engine on "both" tanks.  I have seen equal flow dividers for hydraulic systems but have not been able to find one for fuel. 

Hi. I have just finished running the fuel lines from the top attach points to the fuel valve. I used alloy lines so there would be now replacement needs and reduce the chance of fuel smell in the cockpit. I have to run a return line because I will have a fuel injected engine. I have a surge tank that will have the main return from the regulator and then a vent pipe for any extra overflow going to the left fuel tank only. I cant see a problem with this set up as I can select either tank or both, so I figure that if it starts filling the left tank, I just select that tank until the level goes down equal to the right tank. I usually fly a Jabiru which has a small tank that the 2 wing tanks flow into and depending on the type of flying, eg. circuits etc. the fuel level is often much greater in one tank than the other.

I will try to post some pics of my progress so far. Cheers


Your system looks great except for one thing ... it looks like your holes for your AN bulkhead fittings in the second picture have notched twice into the fuselage longeron.  Did you run this by Zenith or is there some sort of reinforcement on the backside? Caleb told me specifically to NOT cut holes in the fuselage longeron! I'm not an engineer, but it just intuitively seems that notching the longeron would be even worse structurally?  I'm planning to put my fuel line holes in the skin under the longeron.


G'day John,

I am adding a plate to the inside of the skin covering the longeron and extending down to under the wing profile, thats why the holes in the longeron are still open. It should end up as strong or stronger than the origional, I hope :)


Thanks for some great pictures.  I'm going with an Andair selector like John's but haven't decided if I will run my lines as shown by Zenith, or keep them outside the posts to allow for field repairs if I get to do some real cross country trips.  YES, I  know they will be slow trips.


I am doing mine just like John with one difference.  I bought the extension for the fuel valve, so that the lines will come out of the tunnel and straight into the valve, which is flat to the floor.  The extension goes up to the console where the selector switch is located.  It looks like John's selector is mounted on the vertical face of the console.  Mine will be on the horizontal face. This should eliminate any concerns about a low spot behind the selector valve.  

I really like the sound of that, Joe!  Would love to see some pictures!


I'm working on those pictures. I got sidetracked doing the vertical stabilizer. I'll post some soon.

John, I saw this old posting of yours. My gascolator is mounted exactly like yours. Are you happy with the clearance between it and the exhaust stack ?  I have about 3.5 inches of clearance.  Matt Miller


I've got a Jabiru 3300 and it is a light engine, so it is mounted a good distance forward of the firewall for W&B.  The muffler runs transversely across and behind the engine, but it is a good deal further forward than 3.5 inches clearance.  The single exhaust pipe exits below on the left side of the firewall and my gascolator is on the right side, so I have huge clearances and had no problems with my Bing carb.

Ironically, I never had vapor issues but switched from my Bing to an AeroInjector carb and started having occasional "burps" caused by vapor bubbles.  I deleted my gascolator, insulated my fuel line, and installed an inline billet aluminum filter on the cabin (cool) side of the firewall and this seems to have resolved the problem.

I would speculate that your gascolator will probably get a little warm on prolonged taxi or idling.  That might set you up for potential vapor lock issues.  I'd probably put a heat shield between the gascolator and exhaust - leave a generous air gap between the shield and the gascolator and cover the side of the shield facing the exhaust with a self-adhesive radiant heat barrier as is used to shield a floorboard from a catalytic converter.

Out of curiosity, what engine do you have?



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