Ultimate Fuel System Thread / Poll

[142YX]

Due to the ubiquitous nature of this "Sonex Burp" issue, I would like to build a decent database of people's different fuel system setups and attempt to answer the question of how frequently this problem is truly occurring. It seems as if on the Yahoo Groups, every time someone posts asking to take a poll, not many people respond and only the people who have had the worst luck respond.

Please document your fuel system with as much detail as possible, describe the severity (or lack thereof) of any "burps" that you have encountered. Pictures of your setup will be great, and please vote in the poll!

Be sure to include:

-Engine type
-Carb (injector) type
-Gascolator (or fuel filter) make and model
-description of the flow path from tank to carb, everything it flows through
-any unique mods (such as burp tubes, or the like)
-vent type of your tank
-history of burps including severity, weather conditions, operational history, etc

I think this will be a valuable tool to everyone, builder and Sonex veteran alike, in resolving this issue


Edit: due to some confusion about how to vote, please cast your vote based upon your current configuration. When i created the poll, i selected the option to enable users to change their vote in the future, if appropriate.

[MichaelFarley56]

Ill go first on this one...

- I have the stock AeroVee set up with the 7.0 to 1 compression.
- I am using the AeroCarb using the #2 needle, set up slightly rich so I can keep my EGTs reasonable during takeoff.
- I have the Aircraft Spruce/Sonex plans recommended gascolator installed in the plans recommended location. I do have it wrapped with fireproof foam and foil tape to try and keep it cool.
- The fuel is exactly stock per plans with the Home Depot shutoff valve on the tank, an aluminum hard line to the firewall which screws into the gascolator, the gascolator itself with a rigid line running to the MGL fuel flow sensor, a 45 degree fitting, then a flexible fuel line running to the carb. I have the fuel line routed to run right between the exhaust pipes as far away from them as possible, with a silicone fire sleeve over the line.
- Other than the insulation around the gascolator and flexible fuel line, my fuel system is stock.
- My fuel vent is the steel brake line that runs down the front face of the firewall and exits right next to the gascolator. I did bevel the end of that line around 45 degrees into the wind for slight positive pressure.
- After 75 hours and flying in temps ranging from 20-95, I have yet to have a single burp. I guess I've been very lucky.

Ill try to post a picture as soon as I can take one.

[N111YX]

I suppose that Mike and I have the first two votes cast, option one. No big problems.

My cowl will be off shortly for an oil change and I'll get some pics and a description posted...

[sonex1284]

Sonex 1284 (Trigear)
-Engine type - Jab 3300, 100LL only
-Carb (injector) type - Aeroinjector 2.5 needle unmodified
-Gascolator (or fuel filter) make and model - Just a fuel filter, Jegs 555-15034
-description of the flow path from tank to carb, everything it flows through - Tank, strainer, through valve, fuel filter, steel pipe, bulkhead fitting, flex hose (steel braid) in firesleeve,
Aeroinjector. All downhill, no bumps.
-any unique mods (such as burp tubes, or the like) - Nope
-vent type of your tank - Down the firewall per plans.
-history of burps including severity, weather conditions, operational history, etc - None, but warmest weather was in 80-85 so far (cooler in Oregon!)

Picts
https://picasaweb.google.com/1091104510 ... 1027512162

https://picasaweb.google.com/1091104510 ... 5019164002

[aaron_kni]

This thread will provide a great example of how a bullhorn in the hands or 1 or 2 can outweigh and drown out the peace & quiet of 300 others... and that a poll gives a little more equality & perspective on an issue. (Although those who participate in the polls are more likely to be loud by nature so you still wont get the clearest view of reality... ha ha ha)

:-)

I have the factory gascolator, aerocarb & a fuel filter. I sometimes get a burp on the ground after landing and taxing off the runway and reducing to idle. After 640 hours and thousands of landings, it is clear it is a temperature/idle event and has nothing to do with the fact the I have never been able to get the engine to Stop running. I have to starve fuel to convince the engine to stop. PERIOD. The only way to do this is pull way back on mixture until it dies, or go Zero G's or less. Otherwise it will just plain run. No worries.

Aaron
Sonex 1024

[bishoff7]

Sonex running aerovee 2.o
I had the standard install as per plans and run fire sleeve from the gascolator running to the aerocarb with a 2.0 needle running avgas . Burped on take off once the engine was up to temp and used to stall on idle after landing and would not like to restart until you let it cool off a fair bit. This used to occur usually when ambient temp was above 20 degrees C. After a fair few of those I pumped some cold air onto the top and around the aerocarb via a scat hose from in front of the oil cooler and down to a home made shroud over the top of the aerocarb. Did not have that problem anymore
Regards Bish
Sonex 1147

[GWMotley]

My setup:
Aerovee 2.1
Flexible stainless steel fuel line from tank after the fuel valve and filter to the firewall
Hard fittings from firewall to fuel flow then flexible stainless steel line to the carb
No gascolator
All parts forward of firewall wrapped with foam then hight temp insulating tape wrap up to carb
Exhaust are wrapped as well.
Also note that I operate at high density altitudes which I feel adds to the problem

Still note an engine bog on inital full power at take off momentarily, an intermittent hesitatation during cruise, especially just after turbulence at times. I have run both auto gas with ethanol, mogas and avgas with no difference noted. I did have significant issues with the carb in the traffic pattern until I ducted a cold air intake for the carb and can now stay in the pattern all day. My next thought is that we have a fuel pressure problem which has not been addressed as I also note that the hesitation is more often when less fuel is in the tank. So, has anyone run a fuel pump setup yet?

[gammaxy]

What are those with no gascolator doing for a drain? How often do you open the filter to inspect it?

[daleandee]

Just entered my polling information. I have a 3.0 Corvair with a Marvel Schebler MA3-SPA carb with a Usher gascolator. Braided steel fuel lines with fire shield. I have a blast tube from the rear of the baffling to a box that surrounds the gascolator. Never ever have I had the least concern with fuel delivery, starting, or any trace of a burp. I believe this is mostly due to the carb with a float bowl and an engine that runs very cool under the cowling. I use 100LL "almost" always

Here's a video of a hot start:

http://www.youtube.com/watch?v=6FRQmIxvWbs

Hope this helps,

Dale
N319WF

[rizzz]

What are those with no gascolator doing for a drain? How often do you open the filter to inspect it?

From what I remember reading on the yahoo groups, Sonex now recommends not installing a gascolator which would mean they don't think draining is required. They recommend the fuel line as short as possible and go in a straight line (as much as possible) from the tank down to the aeroinjector.

I believe the theory is that with the plastic fuel tank there is much less chance of condensation compared to aluminium tanks. You'll need to search the yahoo groups (which is a pain) where this was discussed.
(I'll do my best to try and find Jeremy's original post).