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  #1  
Old 12-15-2021, 07:17 AM
Jcurry Jcurry is offline
 
Join Date: Jul 2021
Location: Cocoa,Fl
Posts: 75
Default In line fuel filter installation?

Hey Guys,
I was taking off and right at rotation the engine started running rough and vibrating badly. Very alarming. As I climbed out it began to run smoothly. I landed, did a run up, all checked good so I took off with no issues. On the 3rd take off I had the same issue. I did check my fuel (100ll) before T/O and it was clear and free of debris and water. I researched on the internet as well here and I am now aware of the issues with the heavy floats and that the carb jets are very small. Has anyone here installed an inline filter after the gascolator/fuel bowl to resolve this issue?

Thanks,
Jack
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Titusville, Fl
Proud non-builder owner 2011 RV12 N214LA
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  #2  
Old 12-15-2021, 08:25 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,360
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Was the fuel old? Was it a hot day?
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  #3  
Old 12-15-2021, 08:27 AM
Azjulian Azjulian is offline
 
Join Date: Dec 2015
Location: Scottsdale, Arizona
Posts: 207
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Before you do that I would do the following that are all good practice and could be probable cause.

1. check the fuel flow at the carbs (remove the bowls and measure flow over a period of time through each carb)
2. dynamically balance the prop
3. ensure the plunger in the carbs is clean and lubricated
4. perform a static and dynamic engine balance
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  #4  
Old 12-15-2021, 09:30 AM
NinerBikes NinerBikes is offline
 
Join Date: Dec 2018
Location: Granada Hills
Posts: 1,247
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Pull your carb floats and weigh them, see if they are heavy and out of specification. Heavy floats can flood the engine at climb out, cause stuttering, but run fine flying level.

If this plane is new to you, you should probably search around here on how to pull the fuel bowl on the gascolator, and check the filter at the top for debris. Most people check it at their annual, if you do so, get the special locking washers for the bolts instead of safety wire. Do a search here on VAF to find out how to do it, and what you need first, before you pull it apart. It's kind of a bear, cutting the safety wire off of those screws in the location they are in, hence the locking washers suggestion upon replacement.

If your floats are heavy, search on VAF for the big "heavy floats" thread. Some folks are going with aftermarket floats with a lifetime guarantee.
https://vansairforce.net/community/s...=sinker+floats
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Last edited by NinerBikes : 12-15-2021 at 12:18 PM.
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  #5  
Old 12-15-2021, 04:40 PM
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Piper J3 Piper J3 is offline
 
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Location: Hinckley, Ohio
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Quote:
Originally Posted by Mich48041 View Post
Was the fuel old? Was it a hot day?
He is running 100LL so age of fuel and temp shouldn't be a problem. RV-12 is tightly-cowled engine and he is operating in FLA, so could be vapor lock. I would check carb float weights. No need for added fuel filter. See... https://vansairforce.net/community/s...ght=vapor+lock
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PPL/ASEL 1970 - Sport Pilot since 2007
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Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 760

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  #6  
Old 12-21-2021, 06:03 PM
printbr printbr is offline
 
Join Date: Oct 2019
Location: Richland, WA
Posts: 75
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Quote:
Originally Posted by Jcurry View Post
Hey Guys,
I was taking off and right at rotation the engine started running rough and vibrating badly. Very alarming. As I climbed out it began to run smoothly. I landed, did a run up, all checked good so I took off with no issues. On the 3rd take off I had the same issue. I did check my fuel (100ll) before T/O and it was clear and free of debris and water. I researched on the internet as well here and I am now aware of the issues with the heavy floats and that the carb jets are very small. Has anyone here installed an inline filter after the gascolator/fuel bowl to resolve this issue?

Thanks,
Jack
One other thing to check. Is your front tire balanced? If not a few seconds after lift off it will vibrate like crazy and you will think your engine is running rough. Then it spins down and suddenly it runs smooth again. Balance the front tire and it will go away. Its an easy thing to do and may not be the engine at all.
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RV-12 Flying
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  #7  
Old 12-29-2021, 04:35 AM
Jcurry Jcurry is offline
 
Join Date: Jul 2021
Location: Cocoa,Fl
Posts: 75
Default Give that man a cigar!

Quote:
Originally Posted by printbr View Post
One other thing to check. Is your front tire balanced? If not a few seconds after lift off it will vibrate like crazy and you will think your engine is running rough. Then it spins down and suddenly it runs smooth again. Balance the front tire and it will go away. Its an easy thing to do and may not be the engine at all.
Bruce you are correct. It is my nose tire. I didn't think that it could cause that much vibration so I continued down the wrong bunny hole. So after changing floats (old floats were 5.3g in both carbs), and after cleaning gascolator screen I went for a test flight having the same thing happen again with it smoothing out after a few seconds. Remembering what you said, on the next few take offs I was able to do soft field type take offs with no vibration. Then I did a couple where I left the nose down longer and right at rotation she shook like crazy.
Thank you Bruce and to all of you that took the time to give me advice. Very much appreciated!

Looks like HF motorcycle balancer will do the trick.

Thanks,
Jack
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Last edited by Jcurry : 12-29-2021 at 05:48 AM.
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  #8  
Old 12-29-2021, 07:59 AM
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DanH DanH is online now
 
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Location: 08A
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Kudos to both Bruce and Jack. Good call, and a follow-up with the rest of the story. Too many folks never report back.
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  #9  
Old 01-03-2022, 05:36 PM
printbr printbr is offline
 
Join Date: Oct 2019
Location: Richland, WA
Posts: 75
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Quote:
Originally Posted by Jcurry View Post
Bruce you are correct. It is my nose tire. I didn't think that it could cause that much vibration so I continued down the wrong bunny hole. So after changing floats (old floats were 5.3g in both carbs), and after cleaning gascolator screen I went for a test flight having the same thing happen again with it smoothing out after a few seconds. Remembering what you said, on the next few take offs I was able to do soft field type take offs with no vibration. Then I did a couple where I left the nose down longer and right at rotation she shook like crazy.
Thank you Bruce and to all of you that took the time to give me advice. Very much appreciated!

Looks like HF motorcycle balancer will do the trick.

Thanks,
Jack
Here is a great video that explains how to balance the tire without taking it off the plane. I just tied down the tail raising the front tire and did this little trick. You Don't even need the HF motorcycle balancer.

https://www.youtube.com/watch?v=P5wYQzKEuHc&t=130s
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