Shutting down with an Elllison TBI

My RV6a has an O-360 with an Ellison Throttle Body instead of a conventional carburator. It runs wonderfully, but just won't STOP running! Pull the mixture and it keeps popping and sputtering. Turn off the mags and it'll diesel as well. Turning off the fuel value takes a minute or more to burn the gas out of the gascolator. I've gotten reasonably good at killing the mags, then advancing the throttle as it spins down to achieve and incombustible mixture, but even that isn't always working anymore. Has anyone else seen this behavior? Any suggestions? Does my throttle body need a rebuilt or is that "just they way they are"? It really bothers me to have the engine popping and sputtering and even spinning backward on occasion when I'm trying to shut it down. Really hurts the image, not to mention the potential harm to the vacuum pump!

Ellison Query

I have recently retrofitted and Ellison to my O-360-A1A that did have a M-S carb onit. I had noticed the same thing on shutdown. I queried Ben Ellison via his site, and he said it was normal, as idle cut-off on the ellison does not fully stop the fuel flow (idle fuel jet?). He recommends shutting off with mags as well. I get a pretty clean shutdown by moving the mixture to idle cut off and then immediately switching the mags off as the rpm dips. It has got better after correctly setting up the ellison idle etc as per ellison directions. This took a couple of attempts. It works great in flight, I can lean further than with standrad carb, i actually get a power drop rather than rough running/missing on one cylinder. EGT can be leaned with smooth running to about 1400F vs. 13-1350F at best with M-S carb. Ability to lean seems less related to RPM with ellison, with the M-S you couldn't lean far due rough running at some rpms. So overall a better mixture distribution I assume. For aerobatics it works well, and it's light and simple and cheaper than FI. I did plumb in a vapour return line originally, but have removed it now and found no difference. My battery has died the last month and I've had to hand prop it sveeral times, both hot and cold, and my technique is improving! I can start it this way quite reliably now. Can't say I tried this with the M-S for comparison.

Check the set up and go fly I say!!

Grant

Rebuild fixed it...

I too was told it was "normal". But I finally elected to send my TBI back to Ellison for an overhaul. I figured with nearly 500 hours on it and an annual due I might as well. Idle cutoff now stops the engine without fail as long as the trottle is also at idle.

What airbox

Sorry to hi-jack your thread but what set up are you using for the airbox. DO you have venturi throat add on to the entrance of the Throttle body. I was always interested in the ETB but I heard it was sensitive to turbulence entering, but that was years ago. Would you recommend the ETB of a Lyc O-360A1A/180HP, vertical induction. Thanks George

I also have the Ellison TBI on my 0360-A1F6D updraft type Lycoming powered RV6, and it works perfectly. The airbox I am using is the FAB-320 that Van's sells rather than the FAB-360 since the length of the Ellison is shorter than the MS carb that comes on the 0-360 (it is about equal in length to the 320 MS carb). The Ellison does indeed have far beter mixture distribution in comparison to the MS carb, since I can lean it out to 1450 deg F on the EGT before the power starts to drop (no roughness is experienced at all, only a power loss). My CHT's are all within 20 deg F at max cruise power, so obviously the mixture distribution is fairly close on all cylinders (even Bendix FI engines rarely do better than this). I considered adding a SS grid in the inlet of the Ellison, but decided not to since the temperatures were fairly close. Personally, I think the Ellison is a far better (and cheaper) way to go than the Bendix FI setup due to the lower fuel pressure required, and the much lower investment cost!

If your mag switch doesn't turn the engine off, your mags probably aren't getting grounded. Which means you probably have hot mags all the time. Which is a BAD thing

I've never heard of a Lycoming "Dieseling" itself into running after the mags are off. I can shut off the aircraft I fly with the mags while still leaving the mixture full rich.

Etbi

I have an Rv-4 w. O-360-A1A and Ellison EFS-5 installed. I've had teething problems but seem to have them sorted now. I re-fitted my FAB-360 airbox using a bell-mouthed extension I made up from sheet steel welded and hammered into shape. I recently fitted some inlet guide vanes and they have made a small difference. It is more efficient than the M-S carb, cheaper than FI, and I can hand start it quite easily cf. FI (my starter has quit recently). I bought the Ellison 2nd hand and it hadn't been used for 10yrs or so, so I disassembled and cleaned it all with an ultrasonic cleaner (my wife makes jewellery - don't anyone tell on me)! The EFS-5 is for an Cont. O-470, and seemed to go lean at WOT according to EGT, with corresponding roughness (very noticeable on take-off). I have opened up some of the WOT holes in the mixture tube, and I have the idle mixture a bit richer than ideal, as it won't stop completely with mixture only, I have to back up with the mags. This richer idle gives more fuel throughout the range and helps the WOT leanness. I'm happy now it is sorted, and wouldn't pay for FI in comparison. If I build again I would choose it ahead of FI.