Ellison Throttle body questions

I would like to talk to someone who has installed and used a Ellison. I have my plane VERY close to being done and think that I may be running a bit lean. Reasoning is when I go to idle cut off I get no rise in RPM prior to shut down. I have read the ellison tech data that I could find and I have reached out to Ellison with no response.
I understand it is just a spray bar, and that there is an idle speed and mixture adjustment. But one of my questions is, does the idle mixture adjustment affect WOT mixture?
Also any negative issues I have seen talk about inlet geometry. I have the large plenum airbox as ellison suggests the only difference is I offset the inlet to one side of the plenum to align it with the cowling, a small change I believe but wonder if anyone has any thoughts on this since the first time to test it will be first flight out of a 2000 grass strip. My concern being how badly do they run if the air inlet flow is a problem?

N282RV said:

when I go to idle cut off I get no rise in RPM prior to shut down.
. . .
Also any negative issues I have seen talk about inlet geometry.

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The idle adjustment (section 3-4 in the manual) has very little to do with inflight mixture adjustment. You need to get the idle adjustment right because if it's too lean, the engine can die on you at inflight idle. Had that happen once. You might have to cut down an allen wrench to get it on the allen screw that sets the idle mixture.

I have not used the Ellison plenum but if you can get 2500 RPM or more on runup, you're probably good to fly. On mine (Long-EZ) I have to retard the throttle slightly off WOT to get maximum RPM on takeoff. Ellison tells you how to adjust the throttle linkage for that. Turbulence in the airbox is more likely to show up at higher speeds and more-open throttle settings when you're ramming more air into the airbox.

Steve from Ellison fluid systems called me back today, after leaving a message this am. Made an adjustment on the idle tonight, will run up again tomorrow.
I am getting about 2300 static and have a good flying example of my buddy's plane with same set up and he says that's good. Steve mentioned that if it's running good on the ground I should have no prob.
Some of this is nervous excitement...it's that close!

Ellison setup

I fly an RV-6 with an Ellison EFS-4 feeding a Lycoming O-320-E3D through a Van?s FAB for Ellison. The throttle body is oriented so that the throttle slides fore and aft. I am very happy with the operation/performance of this combination as it is currently set up. However when I originally purchased this airplane 18 months ago I was not at all happy with the operation/performance. It took adding one key element to the induction system to make things work (more on that soon). The issue I initially experienced was significant engine roughness while running at high power settings at higher airspeeds. With the original setup I made good power during both static full power run-up as well as during initial full power take-off roll. The roughness however developed during climb out as airspeed increased to Vy. The only way to smooth out the engine was to close the throttle slightly which was not acceptable. I also was experiencing significant roughness during full throttle level flight. The solution was very straightforward. I installed the Ellison Carburetor Grid (flow straightener) PN 08-00814 between the throttle body and the sump and all my troubles vanished. The engine suddenly ran very smooth at all power settings and all airspeeds. It feels almost ?turbine smooth? in comparison. The above part is available from Aircraft Spruce.

I have about 1,400 hours and 13 years on my ETB, with the slide mounted perpendicular to the thrust line, as stated in the manual. I do not have the airflow 'straightener' installed.

I had similar issues with a lack of RPM increase at idle cut-off. After fooling with it for a while, I got frustrated and just flew the thing.

I am not able to run WOT at high speed without enriching the mixture excessively. I believe that this is due to the turbulent ram airflow generated by the FAB. I wonder if this situation would still exist in a 'snorkel' FI air induction setup.

WOT at low speed, i.e. takeoff, is not an issue.

Vapor lock is an issue, and I had several iterations of blast tubes, fuel line routing, and filtering/gascolating before I found a comfortable solution.

Works great for acro.

I read once that Van had installed one once, but took it off because he couldn't get it to run to his satisfaction.

Word is on the street that he's a pretty smart guy....

We have a ETB on a Pitts S1C with O-290. It took a little getting used to but on our bird the mixture has to be full lean for engine start and taxi. In this configuration advancing the throttle past about 1/3 kills the engine. At runup the mixture is advanced with the throttle so as to keep the engine running smoothly at the higher power setting. At the beginning of the takeoff roll the mixture is advanced to full rich right before application of full throttle and kept there for the climb. On hot days (when we have a 8,000 ft DA) it helps to pull the mixture back a smidgen on the lean side of full rich on climb out for maximum power.

The behavior is foolproof since if the pilot forgets to advance the mixture from lean to rich prior to applying full throttle the engine quits. So any takeoff attempt with lean mixture results in the aicraft parked on the runway with a dead engine and an embarrassed pilot. This effect is used in good form to we kill the engine for parking. We make sure that the mixture control is full lean during the taxi in and then when in front of the hangar we advance the throttle past 1/2 to kill the engine, mimicking a carburetor's idle cutoff to the casual observer.

We changed the coxkpit mixture control to a vernier style as the cruise mixture adjustment is very sensitive and the vernier makes it easier to fine adjust compared to a standard push/pull control.

Jim

jliltd said:

The behavior is foolproof since if the pilot forgets to advance the mixture from lean to rich prior to applying full throttle the engine quits. So any takeoff attempt with lean mixture results in the aicraft parked on the runway with a dead engine and an embarrassed pilot. This effect is used in good form to we kill the engine for parking. We make sure that the mixture control is full lean during the taxi in and then when in front of the hangar we advance the throttle past 1/2 to kill the engine, mimicking a carburetor's idle cutoff to the casual observer.
Jim

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I used to use this procedure as idle cut off wouldn't immediately kill the engine. It would kick and buck and eventually, it might shut down. However, per the Ellison manual, if this occurs, they recommend shutting down with your mag switch. I know that sounds odd, but I started shutting down by killing the mags and haven't looked back. No ill effects, loading, or flooding. I confirmed this with another Ellison user who has been doing this for years, per the manual, and reported the same.
It is counter intuitive to every other machine I have operated, but it works well and I have had no hot start issues using this procedure. I would occasionally have flooding issues using your approach. As you know, the Ellison doesn't start when flooded by closing the mixture, so I would be left in no mans land trying to figure out a mid mixture point that would clear out the flooding but still start. A couple times, I had to get out and clear the flooding before I could get started. I just completed a 20 hour trip this summer with air temps 100deg F or better and three or four legs per day for fuel and/or food. It started within two or three blades each and every time. This sold me on shutting down with mags.
Every set up is different, and if you are not having hot start issues with your procedure, no reason to change, but I thought I would mention my experiences.
The Ellison is on my Bucker with an 0320.