Best carb for the Aerovee engine

[wolfpack3]

I don't want to start an argument or in any way insult anyone who is having great success with the Aerocarb however, it has been my experience that it just doesn't work well and makes the Aerovee engine very unreliable.
After trying to adjust the Aerocarb for over 9 hours while in my phase 1 testing and following the directions to the letter, I gave up and purchased a Rotec carb. This too proved to be another waste of money, time and one dead stick landing due to fuel starvation. I feel very blessed to have been working in the pattern and being at the right place at the right time.
After much consideration and frustration I decided to go back to what I know works on a normally aspirated engine...a float bowl carb. I purchased a Zenith carb from Great Planes and have never looked back. With just a few minor mixture adjustments at setup this carb does what it's suppose to do and does it very well. Although I don't have a mixture control in the cockpit I found with most of the flying I do at lower altitudes (6000 and below) it's not needed. I did some mods to get ram air and carb heat but it was a small price to pay for real reliability and peace of mind.
I no longer need to worry about carb issues and whether the humidity has changed the performance. Just my .02 cents.

[SonexN76ET]

Wolfpack3,

I would love to hear more about your issues with the Rotec TBI. What caused the fuel starvation? I just sent mine back to Rotec for inspection due to numerous issues. I put the AeroInjector back on in the meantime and am currently going through the tuning process. I may stick with the AeroInjector if I can get it back in tune.

Also, I would like to hear how your performance compares with the Zenith carb versus the AeroInjector and the Rotec. Would you have any photos to show your configuration?

Thanks,

Jake

[samiam]

Forgive my ignorance, but why is there no mixture control on this type of carb? Without a mixture control, what types of fuel burns are you seeing?

[Mike53]

Forgive my ignorance, but why is there no mixture control on this type of carb? Without a mixture control, what types of fuel burns are you seeing?

The Zenith carb has a mixture control valve on the carb itself and most just set it twice a year ,once in the spring and once in the fall.
Some flying behind the Zenith have used automotive speedometer cables to adjust the mixture from the cockpit but most just make the bi-annual adjustment at the carb because it really isn't necessary unless you plan on flying at higher altitudes most of the time.
As Wolfpack stated they are a reliable trouble free carb , albeit with certain limitations.Great Plains and Hummel engines both recommend the Zenith as a reliable choice.It's old technology but they work .

I also chose the Zenith carb for my Hummel.The other drawback is the requirement for carb heat but that is not a big issue to deal with.
To each his own.Cheers.
Mike

[wolfpack3]

As for fuel burn rate, I flew yesterday for about 1.5 hours and at 3100 rpm at 2500 agl my fuel burn rate was 4.6 gph. I'm probably running a bit on the rich side now due to having a low time engine and will probably tweak the mixture a bit to the leaner side within a few hours.
Thanks for all the replies. I'll try to post some pics when I figure out how to do that.
Wolfpack3

[wolfpack3]

Jake,
In answering your question about the Rotec carb, I purchased a mark1 and after measuring the fuel regulator spring and carefully reinstalling it, I think this is the weak link in the Rotec. EVERYTHING depends on that spring working properly all the time. I was also in touch with Rotec but their customer service leaves a lot to be desired. I hope you have better success than I did. Talking to the owner, Carl, I thought he was really full of himself at SnF.
Wolfpack3

[wolfpack3]

Here are some pics of my Zenith carb setup, the carb heat/ram air control is on my throttle quadrant.

[bakfly]

All builders using the Aeroinjector and having problems with the needle adjustment check your needle diameter.
For the first 9hrs using needle # 2, 2.5 and later # 2 again and not be able to tune the Engine properly I was desperate to get this sorted out. I decided to measure all the needles I had, # 1, 2, 2.5 and # 3 needles tapers and diameters. I came to an interesting conclusion. The tapers on needle # 2 and 2.5 are the same until about halve way from the tip. I was puzzled why the engine did not idle properly with needle # 2 and did idle fine with # 2.5. After measuring the diameter with a micrometer I found the problem. The diameter of the # 2 needle is 0.05 mm (0.002") smaller than #2.5. Needle # 2 is 3.14mm (0.1236") while needle # 2.5 is 3.19mm (0.1256"). This made it rich on idle because fuel could leak pass the needle and not be able to lean it out. After getting a new # 2 (3.19mm) needle from Sonex it was a different Engine. Easy to tune and running very well during WOT and Idling.
If you have a needle what does not fit tightly in the needle holder but fits in sloppy, than most likely the needle diameter is to small and you will not be able to get it running properly. Other builders had the same problems and replacing the needle solved there problem.

My Aerovee with the Aeroinjector has done now 105hrs and running beautifully with idling, WOT and cruising.

Peter Bakker
Sonex 1430 Aerovee 2.1
Australia

[kevinh]

Peter - that is awesome. Saving it for later...