by SonexN76ET » Thu Dec 18, 2014 7:45 pm
While you search for a fellow builder in the Raleigh area to assist you with your AeroCarb there are a few things for you to consider. You should also know that my Aerovee runs better than a Lycoming - really.
The first start of any new engine is an experiment. It takes patience to properly tune and configure an engine. What type of engine do you have?
What I have posted here is all in the Aerovee and AeroCarb manuals but your focus may be unjustly on the AeroCarb. First I am assuming you have some type of VW engine conversion. In tuning an engine with an AeroCarb you also need to consider the ignition timing, induction leaks, air intake, camshaft alignment, and fuel system. A problem with anyone of those items can potentially make you think you are having problems with your AeroCarb. For instance, make sure your fuel line routing is to specifications. If you have a bunch of ups and downs in your fuel line you could have air bubbles trapped in the line or it could cause restricted fuel flow. Also, make sure your filter screen and fuel filter are clean and that there are no sharp bends in your fuel line restricting fuel flow. You also want to make sure your fuel is clean and free of water. Follow EAA's and FAA's guidance on verifying proper fuel flow.
There are other things that can cause a poor running engine such as improper camshaft alignment with the crankshaft (this has happened to more than one unsuspecting builders and they did not discover it until first start), or you could have your ignition trigger magnets installed backward as a few builders have done. I know of one builder whose camshaft alignment was off by a couple of gear teeth. The engine ran, but ran kind of like you describe your's running.
A dirty air filter can cause difficulty setting your AeroCarb properly.
Leaks in your induction system can cause a poor running engine too. Make sure your intake elbows are properly sealed and seated. Make sure all the hoses on the induction system are tightly secured. I had an induction leak and never even considered that a possibility when I first set up my engine until I called Sonex and they suggested I double check for leaks.
If you set your AeroCarb to the initial settings specified in the manual, the engine (with everything else properly configured - timing, camshaft, fuel system, etc.) should run fairly decently (i.e. stock needle, with proper side up, and lined up as shown in the manual). After that the primary adjustment you will make is to the mixture needle setting.
I wish you the best of luck and look forward to seeing you in the air! Please keep us posted on your progress. Hang in there, you will get this all sorted out. Just be patient and methodical (try one thing at a time). Even factory engines are tricky to get properly set up. Like everyone else here has said, follow the manual to the letter and work with the Sonex Tech support crew, they know what they are doing. Most of all be safe.
Sonex Tri Gear, Rotax 912 ULS, Sensenich 3 Blade Ground Adjustable Propeller
MGL Velocity EMS, Garmin GTR 200 Comm, GTX 335 ADS B Out Transponder
ILevil AW AHRS & ADS-B In, UAvionix AV20S
200+ hours previously with Aerovee engine
Sarasota, Florida