Ea81 Altitude Compensating Carbi?????

[asra]

OK,I'm looking for what options I have for replacing my single subi carbi with an altitude compensating one?Anyone had any experiences with this, does any brand or type make installation easier?For simplicity I'd prefer to stay with a single carbi. Is this possible?[?]Ross B

[asra]

Ross, you could go one step better and use throttle body fuel injection, mine has given me about 200 more rpm. It took me along time, but I now know all the pitfalls, I think.John EvansThink logically and do things well, think laterally and do things better.

[asra]

Thanks JohnI want to keep my machine as simple as possible, so I can maintain and service it in remote locations with the limited numbers of tools, and me doing the service. I'd rather stick with a carbi set up if possibleRoss B

[Tim]

Ross, I would have to agree with John. If you do wish to keep it simple (read cheap) then the SU or the CD Stromberg are the carbys you are looking for. The SU is the most readily available and a suitable one is found in wrecking yards on Austin 1800's.Advantages - Very light weight, air pressure compensating, in flight mixture control and far less prone to carby ice.Disadvantages - 0 to 30 degree (from horizontal) mounting angle, requiring a curved adaptor to fit a standard manifold, and must be set up jetting and mixture wise (not very hard).Tim McClure

[asra]

This is the way I have been investigating for the reasons Tim just mentioned particularly in flight adjustment the reson for this is if you get a tank full of poor fuel you can make necessary adjustments Butch.

[asra]

Sticking my neck out as usual Ross, I would contend that once you have throttle body fuel injection set up properly the only servicing required will be the fuel filter, whreas carburrettors as complicated finicky devices by comparison. The computer trouble-shoots itself, and all you need to check the sensors is a small multimeter.John EvansThink logically and do things well, think laterally and do things better.

[asra]

Ross,here is a carby/manifold that Eric Hoskinson has,contact him for more details..Image Insert: 45.76

[NiqueNaque]

The bloody pirate...It looks like the manifold I made...Cheers,Nick.

[Echo]

Me 'pirate' something off you , Nick ? That would be a joke. Ross, the manifold is stainless steel with a SU carby ( not sure what size).The only problem is the manifold being one peice might not suit an engine that has had the heads machined to raise the comp.( It should have a slip joint one side )

[asra]

John How is your fuel economy with the fuel injection?Do you have any pictures of the set up you have installed?ThanksRoss B

[asra]

Ross, I don't have any fuel consumption figures yet, but my impression is that it is quite good. Now that the oxygen sensor has settled down I don't seem to need the enrichment knob - it simply adds resistance to the temp sensor so the computer thinks the engine is cold. Initially I seemed to have to enrich for high power settings and then lean for descent - I forgot to do it once and sooted the plugs up during final. The LED readout on the Jaycar display works well.I haven't taken any pictures yet. Might fly up to Denman some time.John EvansThink logically and do things well, think laterally and do things better.

[asra]

Ross, here are a few pictures I just took, let me know if they're not self-explanatory.I fitted the system off a JD Camira. You have to get everything including the wiring harness.Image Insert: 80.72

[asra]

Missed one!Image Insert: 77.7

[asra]

Personally Ross, I think efi is the way to go. I am have tremendous success with my Hirth and I believe it is the way to go, esspecially for a 2 cycle engine. Check out this site at http://www.msefi.com/index.php Ross, you can even build your own unit and the information is well worth while.

[Brian]

Boy, after having a carby EA 81 for 1000 hours and having a Fuel Injected EJ 2.2 for 1700 hours, I know which one I prefer !!!Only thing is that you cannot skimp in the fuel filter department but the same rings true for any motor. I run a Racor finer filter FI unit as primary and a Z 200 FI unit as a secondary and replace both at 100 hours and have had absolutely NO problems which couldnt be said for the carby EA 81which at one stage I actually carried a spare carby to save downtime !!Just one thing with FI motors, I have had a fuel pump fail at approx 750 /800 hours and wonder if anyone else has had similiar problems ??Brian