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Carb Drip Trays...

Piper J3

Piper J3

Well Known Member
Both of my carb drip trays are cracked from vibration with 900TT and are being replaced with new. Question…. I have seen on Synergy-built legacy RV-12 where they have a silicone type doughnut (3/4” round) wedged between bottom of carb float bowl and the drip tray... I assume to limit vibration of the sheetmetal tray. Does anybody have information about this part? I don’t see reference in KAI….
 
Piper J3 said:
Both of my carb drip trays are cracked from vibration with 900TT and are being replaced with new. Question…. I have seen on Synergy-built legacy RV-12 where they have a silicone type doughnut (3/4” round) wedged between bottom of carb float bowl and the drip tray... I assume to limit vibration of the sheetmetal tray. Does anybody have information about this part? I don’t see reference in KAI….
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When I built my ELSA the KAI told us to put a blob of ProSeal between the Drip Tray and bottom of the Float Bowl. Used a wire or thin blade to slice it when removing carb for the first time.
 
At 1300 hrs my right one cracked in the right side radius. I made a new piece removed the cracked one and replaced it. There is a fillet of proseal in all corners that probably helps dampen the movement. Carb balance and dynamic prop balance are your friend.
 
Page 46-07 (Rev. 2), Steps 3-5 of the RV-12 Plan Set describes the installation of a vibration dampener for the carbs.
 
After a flight - I had my right carb leak gas, I think from the overflow tube and leak down on the hot exhaust. I don't like that!!! I haven't inspected yet, but I order the new MS80-430 cause it maybe heavy floats. I at around 300 hrs on my 2010 RV-12.

MY Question: anyone use these fiberglass drip trays, that catch the fuel and tube it away? >>> Would they get to hot? >>> See any problem?

DRIP TRAY AT SIDE SLIP AVIATION

1722266851264.png
 
RV12_AL said:
After a flight - I had my right carb leak gas, I think from the overflow tube and leak down on the hot exhaust. I don't like that!!! I haven't inspected yet, but I order the new MS80-430 cause it maybe heavy floats. I at around 300 hrs on my 2010 RV-12.

MY Question: anyone use these fiberglass drip trays, that catch the fuel and tube it away? >>> Would they get to hot? >>> See any problem?

DRIP TRAY AT SIDE SLIP AVIATION

View attachment 67360
Click to expand...

The RV-12 has metal drip trays already for the carbs. Do you not have those? See RV-12 KAI 46-06 and 46-07.

1722275340670.png
 
Early RV-12s had a very flimsy metal drip tray assembly, mine were cracked almost all the way through. I looked at the updated KAIs to order new parts and noticed that the trays were redesigned and are now much better. See drawing 46-06 or page 46U-07 for the new part numbers.
 
I do have the flat metal trays and in great shape, but the fuel just runs off the back side and drips on the hot exhaust. I want to catch the fuel and drain it safely away, if a leak happens.
 
RV12_AL said:
I do have the flat metal trays and in great shape, but the fuel just runs off the back side and drips on the hot exhaust. I want to catch the fuel and drain it safely away, if a leak happens.
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Which side are you calling the back side? The forward side of those trays is supposed to have fuel tank sealant so the only way for fuel to drip would be aft. That should be far enough back that it isn't hitting the exhaust. If you are dripping enough fuel for this to be a problem, your carbs probably need service.
 
I bought the newer designed trays from Lockwood, when I had the older trays I was told the right tray was more likely to crack and to add silicone at the bottom to contact carb float bowl to dampen vibes. They said for some reason the right carb area produced more vibes which I believe is true since I had the needle valve attach bracket crack causing fuel to run out of the carb air inlet. Also there are early model float bowls that have the float guide pins pressed into the bottom with the bottom of the pin seen form the outside of the bowl, had one pin (RH Carb) come loose exposing the hole causing major fuel leak. You can either add a drop of epoxy to the outside of bowl or get the new bowls, the early bowls were a poor design.
 
bobg56 said:
I bought the newer designed trays from Lockwood, when I had the older trays I was told the right tray was more likely to crack and to add silicone at the bottom to contact carb float bowl to dampen vibes. They said for some reason the right carb area produced more vibes which I believe is true since I had the needle valve attach bracket crack causing fuel to run out of the carb air inlet. Also there are early model float bowls that have the float guide pins pressed into the bottom with the bottom of the pin seen form the outside of the bowl, had one pin (RH Carb) come loose exposing the hole causing major fuel leak. You can either add a drop of epoxy to the outside of bowl or get the new bowls, the early bowls were a poor design.
Click to expand...
If you got drip trays from Lockwood, they are probably the Rotax drip trays, not the RV-12 drip trays. The RV-12 KAI says to bond a small nub of fuel hose to the bottom of the trays with fuel tank sealant to form dampeners.
 
I'm going to rebuild both carbs and replace floats, it's annual time anyway. I was only asking about the drip trays I linked to above. They seem much more safe, encase of a future fuel.
 
seagull said:
Consider moving your vent lines and the drip tray style you use is not as important.

Carburetor Vent Line Reposition – Seagull

waltsrv12.com
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I couldn't open your link with Firefox cause it says "Secure connection cannot be established". I just got it open in Edge.

seagull, I like that. Did it help your carbs?

I'm going to do this - so 1/8 Tygon F-4040-A tubes (I found on Amazon) and 1/8″ stainless tubing (found on Amazon).

Thanks - Wallace
 
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