In line fuel filter installation?

[Jcurry]

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

[Mich48041]

Was the fuel old? Was it a hot day?

[Azjulian]

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

[NinerBikes]

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

[Piper J3]

Originally Posted by Mich48041

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

[printbr]

Originally Posted by Jcurry

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.

[Jcurry]

Originally Posted by printbr

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

[DanH]

Kudos to both Bruce and Jack. Good call, and a follow-up with the rest of the story. Too many folks never report back.

[printbr]

Originally Posted by Jcurry

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