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Rotax 912 200hr Carb Removal & Inspection

MrSparkle

Member
Approaching 400 hours which means a 200 hour maintenance/inspection. One item is the removal and inspection of the carbs; is the intent to fully or partially disassemble the carburetors?

If the carbs are to be disassembled, I don't feel comfortable doing this (actually I'm okay taking them apart, its the putting back together that gives me pause) and would appreciate suggestions on who I can trust with this work. Both positive and negative experiences would be appreciated, also shipping advice.

Thanks in advance for your replies.

__________________
Ian Heritch
San Antonio, Tx

RV-12, N417E, Randy Pflanzer's Red Venom 2
 
I use Leading Edge Airfoils and have been very satisfied.

After I took the class there and saw what they do including removing all the plugs in the castings and reinstalling them with epoxy, I decided I'd rather have someone who rebuilds these carbs everyday and has all the cleaning equipment do it, not me. They will also incorporate any of the running changes.

Jim Butcher
Rotax 914
 
I used a west coast maintenance center for ROTAX. They swapped my choke modules which made starting almost impossible. I took everything apart myself to find their screw up and fixed it. Just because you deal with a big name don?t expect they?ll get it right. Next time I?ll use Lockwood for overhaul.
 
I second Lockwood Aviation. They have done my 5 times over the years.
Hint: Remove the throttle arms, with the cables connected, from the carbs. Leave them in the airplane. That way it will be close when re-sinking the carbs when you reinstall them. Furthermore you can remove the choke arms to, but there is a special trick to that maneuver. :D
 
I second Lockwood Aviation. They have done my 5 times over the years.
Hint: Remove the throttle arms, with the cables connected, from the carbs. Leave them in the airplane. That way it will be close when re-sinking the carbs when you reinstall them. Furthermore you can remove the choke arms to, but there is a special trick to that maneuver. :D

Hey John, so what is the "special trick" you mentioned regarding choke arm removal. I need to do some carb work and my choke cables are frayed to the point that I think it will be impossibly to re-install them..........Tom
 
Remove the Spring on the Carb Arm.
Remove the Nut that holds the Carb arm on the Carb and remove the carb arm off the carb.
Remove the Spring from the Throttle Arm.
Remove the Nut that holds the Throttle arm on the carb and remove the throttle arm from the carb.
Now remove the L shaped brass colored bracket that both cables thread through on the top outer edge of the carb by removing the carb assembly from the rubber
cup and slowly twisting the entire carb to loosen the brass tube that holds the carb cable. This part requires some thought and patience.
Now you should be able to remove the carb and leave the rest hanging on the engine without removing the cables from either arm.
I think thats about it, Im working from memory so I might have missed something.;)
 
Hey John, Thanks for the prompt response. I'm fighting a rough running problem and I may end up tearing the carbs down. I made a big mistake during the build. I cut the 2 choke cable short, only about an inch past the cable lock nut. I failed to use a true cable cutter, and did it with common dikes, and the ends are all frayed out. Fortunately, I didn't do that on the throttles, was able to use a real cable cutter and they are perfect. I am considering buying a new choke cable (at $95). If I thought that I could just pull the old cable out of the housing and install just the new cable, without having to replace the housing, I would probably do it. I just hate the thought of replacing the housing and all............Tom
 
Cutting or terminating a cable

On the EAA site there is a builder assistance video section where Brian Carpenter shows how to ?cut? a cable with heat from a torch and using a slow turning drill. When I changed my throttle cables to the vernier control I used this technique to ?cut? the cables. There was no gas in the carb and when I determined where to put the torch flame I used a piece of metal to create a shield. It worked well and created such a nice cable end.
Also on the choke cables if you are considering replacing you might give McFarlane a call to see if you sent them your mechanism if the would re-cable it. Worth an inquiry I?d think.
I too had some issues with my choke cables and went to a bicycle shop to get a proper cutter and some advice about fraying. They use a proper cutter and gorillas glue on the cable end to help seal/bond the strands. Some ideas to look at. Good luck.
 
Thanks for the McFarlane tip. I wasn't sure who made the cable. I bought my verier throttle form them. That was during the build and about 4 years ago, and way before Van's offered them. Building EAB has it's advantages. I'll call them in the morning.....Tom
 
When I cut a cable I thread it through the attachment and then put heat shrink over the cut point. Then causing cable cutters I cut in the middle of the heat shrink for a nice clean end.
 
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