Monocock
03-13-2011, 12:15 PM
I thought I would add my recent experience with 912 carb rubbers here as I am aware they are considered a weak point on the set up.
I recently had a carb work loose on my 912s and I loosened off the clamp, re-positioned it and flew some more. Within an hour or two it did the same again. The carb body came away at the base but the top part of where it clamps it remained in the socket. I took the socket off and was amazed to find the internal retaining rib had sheared off on the lower section of the rubber and there was also a small chunk of rubber missing.
The rubber socket was replaced and and I am amazed at how much smoother the engine is running. I am sure there was air getting past the clamp and affecting the mixture on that side and she is sewing machine smooth again.
There were no visual clues from the outside of the carb rubber that there was a problem lurking inside. From now on I have decided to consider these rubbers as a part of a 25 hour inspection as I could not believe what condition they were in inside.
Just thought this might be of use, especially to the 100hp brigade as some of those hard starts can't do much good to items such as this. I had a GSC prop on her for 15 hours a while back which vibrated like a road roller and I think that might also have contributed to the problem too.
I recently had a carb work loose on my 912s and I loosened off the clamp, re-positioned it and flew some more. Within an hour or two it did the same again. The carb body came away at the base but the top part of where it clamps it remained in the socket. I took the socket off and was amazed to find the internal retaining rib had sheared off on the lower section of the rubber and there was also a small chunk of rubber missing.
The rubber socket was replaced and and I am amazed at how much smoother the engine is running. I am sure there was air getting past the clamp and affecting the mixture on that side and she is sewing machine smooth again.
There were no visual clues from the outside of the carb rubber that there was a problem lurking inside. From now on I have decided to consider these rubbers as a part of a 25 hour inspection as I could not believe what condition they were in inside.
Just thought this might be of use, especially to the 100hp brigade as some of those hard starts can't do much good to items such as this. I had a GSC prop on her for 15 hours a while back which vibrated like a road roller and I think that might also have contributed to the problem too.