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  #1  
Old 07-20-2021, 08:01 PM
jpowell13 jpowell13 is offline
 
Join Date: Nov 2008
Location: Baton Rouge, LA
Posts: 694
Default Inspecting the gascolator

I'm probably the only one on the website who hadn't figured this out. Year after year at inspection time I sweated getting the bowl off my blue Vans gascolator. Even with the sump valve opened vapor lock wouldn't let go. Today it occurred to me to remove the plug at the top and use my compressed air nozzle to pressurize it. Pow! Came off with authority! Next time I'll adjust the regulator down to about 5psi. John
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  #2  
Old 07-20-2021, 08:25 PM
Taltruda Taltruda is offline
 
Join Date: Oct 2017
Location: Las Vegas, NV
Posts: 766
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Yikes! On reassembly, try some fuel lube or Dow Corning O-ring grease on it. Even motor oil if thatís all you have.. It should just slip up and back off.
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RV-8 empenage finished 10-2020

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  #3  
Old 07-20-2021, 08:41 PM
jpowell13 jpowell13 is offline
 
Join Date: Nov 2008
Location: Baton Rouge, LA
Posts: 694
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It's already reassembled Tom. I'll do that next year though. John
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  #4  
Old 07-21-2021, 05:35 AM
RV7 To Go RV7 To Go is offline
 
Join Date: May 2011
Location: Ontario, Canada
Posts: 313
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Quote:
Originally Posted by jpowell13 View Post
It's already reassembled Tom. I'll do that next year though. John
I have found Fuel Lube to be too sticky. I have been using Krytox 205 for the last 7 years. Works great on fuel valves, fuel caps, gascolators....It is expensive but only requires a very light coating on the seal and lasts over a year on my fuel caps etc. FWIW.
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  #5  
Old 07-21-2021, 10:15 AM
edstepec edstepec is offline
 
Join Date: Jul 2013
Location: oregon City,OR
Posts: 13
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I experienced RV6A power loss the other week and contributing this to air bubble in the gascolator. I have the Cessna "pull the lever up" style gascolator. I had issues with getting flow. HEre is an excerpt from the CEssna forum:
************************************************** ****
A couple of caveats to throw out there - just went thru this so I speak from experience!

Doing this involves draining all of the fuel from the aircraft and then refueling once done. Simple enough or so it seems.

If your system is like most Cessna's it is gravity feed only. When done and you put the fuel back in DO NOT BE SURPRISED if, when you drain your gascolator nothing or just a dribble comes out. The lines from the fuel tank to the aircraft subfloor are near vertical and will airlock. When I recently did mine I put 25 gallons of fuel back in and had a fast drip at best at the gascolator??? You would think that this is impossible but it's not. There is only a couple of feet or so of "head" on the system so an air bubble will easily stop or slow the flow significantly.

I gently blew into one tank opening while sealing off the vent and still nothing. I shook the wings a bunch and still just a dribble. Went to lunch and tried afterward and a little surge of fuel then back to a trickle. :-(

I knew what was going on but I didn't have a good way to hook a suction up to the line so I just left it overnight. The next morning it came out normally at the gascolator. Problem solved by itself.

BE SURE that once you get good flow at the gascolator to purge the gascolator to carburetor line by loosing it at the carburetor until a good flow comes out of it also.

If you don't prime the lines they will EVENTUALLY purge themselves but during that time you can/will get erratic fuel flow which could happen at a bad time. :-(

The biggest point of my post is if you repair your fuel selector etc. and then don't get any fuel flow DON'T start second guessing what you did and take it back apart - give it some time or hook up a suction to it. It's probably just airlocked.
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  #6  
Old 07-21-2021, 12:34 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
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Quote:
Originally Posted by edstepec View Post
I experienced RV6A power loss the other week and contributing this to air bubble in the gascolator. I have the Cessna "pull the lever up" style gascolator. I had issues with getting flow.
The Cessna "pull the lever up" style gascolator was designed to be used on gravity flow systems. You are using it on your pressure system. I see two problems with the failure of the seal around the pull shaft.......

1. When it fails, it can suck air into the fuel line with the mechanical fuel pump.
2. Allow fuel to escape (major fuel leak) when the back up electric pump is turned on.

The sample valve in the fuel tank is the lowest location in the fuel system and that is where you will find water. If you still find it necessary to run a gascolator, at least use the one offered by Van's.
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  #7  
Old 07-21-2021, 09:06 PM
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koupster koupster is offline
 
Join Date: Dec 2013
Location: SLC, UT (KBTF)
Posts: 288
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Quote:
Originally Posted by jpowell13 View Post
It's already reassembled Tom. I'll do that next year though. John
John,

Just remember that any pressure you put into the gascolator also acts on the carburetor bowl and has the possibility of collapsing or otherwise damaging the float.

If you don't have Dow Corning O-ring grease or Krytox 205 handy, Sil-Glyde from NAPA will do the job. https://www.napaonline.com/en/p/BK_7...&gclsrc=aw.ds&
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RV-6A - KBTF
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  #8  
Old 07-21-2021, 09:58 PM
jpowell13 jpowell13 is offline
 
Join Date: Nov 2008
Location: Baton Rouge, LA
Posts: 694
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Thanks for sharing David. I'll ground test the engine and make sure the carb is not flooding. Will also grease the o-ring next year, but the o-ring doesn't seem to be sticking. The problem is that it's being held on by vacuum. I don't remember if I tried to pull the bowl off after removing the plug. It probably would have slid right out of the top piece if I had. John
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  #9  
Old 07-22-2021, 11:10 AM
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koupster koupster is offline
 
Join Date: Dec 2013
Location: SLC, UT (KBTF)
Posts: 288
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John,

My gascolator bowl was pretty sticky the first time I removed it. It's been fine since then after being lubed.
Pushing in the quick drain to break the vacuum while you twist and wiggle the bowl on your next removal may be helpful.
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RV-6A - KBTF
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  #10  
Old 07-22-2021, 10:32 PM
jpowell13 jpowell13 is offline
 
Join Date: Nov 2008
Location: Baton Rouge, LA
Posts: 694
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Test flew for about 40 minutes today after replacing all my fuel/oil lines, fuel pump, spark plugs, induction tube couplings/gaskets and doing all those engine compartment checks for the annual. All good. Stopped by my local supplier and bought some fuel system lube on the way home. I'll use it next time I have the gascolator bowl off. In the mean time, I'll try it out on the fuel tank caps.

Now, on to the fuselage, wings and landing gear. Think I'll convert the halogen landing lights to LED while I'm at it.. Flying is more fun than inspecting and maintenance, but the plane gets a little better every year if you do it right. John
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