Rotec tbi

[WaiexN143NM]

Hi all,
I thought id start a new thread on this topic, we hijacked the throttle cable thread. Any one with a rotec tbi please post your experiences. And a question for loren and john, what were you using for fuel? 100LL or auto fuel? . We run 100LL exclusively. We have a mark 1 and have had no trouble so far. We have the separate regulator that is mounted on a angle 90 degree AN fitting right before the tbi. Then a short alum angle mounted on regulator with an arm to depress the primer button, which is hooked up to a cable run to the cockpit. How many hours on your regulator before any trouble appeared? Understand correspondence w rotec factory is spotty. Did anyone take it apart and see an obvious defect/failure? Could it be the diaphram , spring, or o-ring? Thanks.

WaiexN143NM
Michael

[Fastcapy]

The overall performance of mine is way above what I experienced with the aerocarb and aeroinjector I tried on my plane.

Pros:
- 125 more static rpm
- 200 more rpm WOT in level flight
- No aerocarb burps on takeoff
- Better, more even CHT's and EGT's.
- Sounds throatier. To the point where people asked if it was a different motor.
- Better perfomance pulling G loads. My aerocarb/injectors would go way rich and I would have to lean before acro which I wasn't a fan of.

Cons:
- Support isn't nearly as good as through Sonex
- Mounting it wasn't as straight forward as the aerocarb
- After flying awhile and landing with a hot motor/cowl area it doesn't want to idle while taxiing. I think it is because it is going rich due to the heat. Unlike the aerocarb the idle mixture is set and pulling the mixture control doesn't lean out the idle circuit. I figure this is the issue because of how far I had to lean the aerocarb after landing to keep it running.
The idle issue when hot and taxiing is the one frustration I have with it. If I could get that nailed down I would be a happy camper. I don't know if cold air intake is the way to go or if a fuel pump would help of if trying to make some way to remotely adjust the idle mixture screw is the answer.

Otherwise, I am very happy with the overall performance I have seen from the TBI.

[WaiexN143NM]

Hi mike,
Thanks for the post. What about adding the side cooling vents like the b models? On the ground would it also help the cooling? Maybe the propwash going over the sides to 'draw' out the hot inside air? Just a thought. Our trouble with the aerocarb was when the engine is started(jab 3300) you couldnt move the throttle . The induction draft stuck the slide. And yes we bought the upgraded cable, it was supported for flex, and orientated the right way. Hence the rotec. We've had ours stumble while taxiing , after a flight and stopped to refuel. Then taxi back to hangar , a few stumbles in engine , from the heat soak. The b model side vents are avbl from sonex. About $125 for a set of 2. Thinking of installing them to test.

WaiexN143NM
Michael
Jab 3300
Full dynon w autopilot(love it for x-c)

[fastj22]

I've run both auto and 100LL through the TBI. had a full tank of 100LL when my regulator stopped the fuel flow. I took it apart and found no anomaly. Reassembled and it worked fine. I assume something got just a bit of out adjustment and reassembly realigned it.

The regulator is a very clever design. It only gives the TBI just as much fuel as it needs. It is also complicated and sensitive. It is a single point of failure. It is not fail safe. If it sticks/fails, you must immediately override it with the primer, flooding your engine. If that keeps your engine running, you may get home. If not, you will be looking for a landing spot.

My advice is understand how the regulator works and make your own choice to fly behind it.

[WaiexN143NM]

Hi john, all,
Do you think that running auto fuel, even one tank could have caused some damage to the diaphram? Did the auto fuel have ethanol in it? Im thinking some damage to the elastic quality of the diaphram? When you took it apart was it soft and pliable? Loren, did you run any auto fuel? With ethanol? Fairly simple w spring diaphram pin and o ring. Also mike beck did you ever run any auto fuel? We run 100LL exclusively. Any one else on the rotec tbi problems or fuel use question?

WaiexN143NM
Michael

[lgsievila]

Hi Michael,
I ran av gas and auto gas but never any ethanol. We have a local distributor near the airport that sells a lot of 92 octane non ethanol so there was a lot of turnover in the source. Never saw a drop of water in it and I tested religiously. Also had the proper in line filter.

[fastj22]

The internals of the regulator looked like new. Like I said, when I reassembled, it worked fine. There is nothing in the manual indicating a prohibition on using auto fuel.

[WaiexN143NM]

Hi john ,
Thanks for reply. Was just wondering if ethanol would have degraded the diaphram. Yea funny just taking apart and reassembly and works fine. I like your aerocarb with the rotec slide. Have you flown yet ? Be good and let us know how things go.

WaiexN143NM
Michael

[fastj22]

Hi john ,
Thanks for reply. Was just wondering if ethanol would have degraded the diaphram. Yea funny just taking apart and reassembly and works fine. I like your aerocarb with the rotec slide. Have you flown yet ? Be good and let us know how things go.

WaiexN143NM
Michael

No, weather hasn't cooperated. Gusts to 50 today. Decided to do my condition inspection since I have everything apart. Which of course turned into redoing some sheet metal on the bottom of the cowl for "improvements". Also just realized I'm two weeks out of currency and need a BFR.