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  #1  
Old 04-16-2015, 12:21 PM
Jim garrett Jim garrett is offline
 
Join Date: Apr 2015
Location: Friendswood, texas
Posts: 10
Default Engine problems

I just completed my RV-12 and have 14 hours on it. I have the skyview touch installed. Everything is normal on first flight but after landing and shutting down for up to 30 minutes, the engine is hard to restart but it will start after running the starter more than it should. I realize this is vaper lock. The real danger however is when I go to take off. About halfway down the runway ( short runway) the skyview indicates a warning about fuel and the indicator (amount of fuel) turns red and indicates around 11 gallons per hour. I also sometimes smell a gas smell. It then settles down to the normal 6 to 7 gallons per hr and everything is normal about the end of the runway. I noticed only one time -- with top cowl off and aux pump on that fuel was coming out the plastic overflow tube with engine turned off. I took carb off and noticed that float was sticking the first time I moved it. I also checked the valve that the foot shuts off when full and it was clean.
Has any one had this happen to them and any thoughts on how to repair
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  #2  
Old 04-16-2015, 12:40 PM
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MacPara MacPara is offline
 
Join Date: Apr 2010
Location: Tucson, AZ
Posts: 461
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I live in Southern Arizona and see similar issues when restarting the engine in the summer after sitting on the hot tarmac for any length of time.
What I do to help it a little is to run the electric fuel pump for half a minute before restarting the engine (I added a switch for my electric pump). Do not use any choke on restart, play with the throttle a bit if needed to get it fired up. It usually runs a bit faintly when it comes up and I let it run until I feel that it runs as usual before doing anything else to it. Once it's running I have not seen any delayed vapor issues, like high fuel flow.
Your fuel smell indicates that there is something else but vapor lock going on. It should be a problem with the floats in your carbs as you had already seen. You might want to clean hem out thoroughly and also check that the spring valve in there is working ok.
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  #3  
Old 04-16-2015, 05:48 PM
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Ironflight Ironflight is offline
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Location: Dayton, NV
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Hey (former) neighbor - welcome to VAF!! Glad to hear you have the -12 flying.

So Polly hasn't gotten any longer, huh?
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  #4  
Old 04-16-2015, 08:25 PM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by Jim garrett View Post
I noticed only one time -- with top cowl off and aux pump on that fuel was coming out the plastic overflow tube with engine turned off.
Fuel exiting the vent tube could be caused by debris preventing the needle valve from fully closing, floats sticking (as you thought you saw already), or sinking floats (have you inspected the floats in accordance with the recent S.B.?)

Fuel being vented would also align with a higher fuel flow indication.

I would say that high fuel flow, along with fuel smell some of the time, is a strong indicator that you are venting fuel... something that you should definitely get resolved.
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  #5  
Old 04-17-2015, 05:21 AM
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f1rocket f1rocket is offline
 
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Location: Martinsville, IN
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Just to add what others have already said, there is also a recall on some of the fuel pressure sending units. Check on the Dynon web site for the particulars. This is just to make sure you are getting an accurate fuel pressure reading.
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  #6  
Old 04-21-2015, 06:06 AM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
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Any findings yet?
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  #7  
Old 04-24-2015, 08:01 PM
RV12John RV12John is offline
 
Join Date: Oct 2014
Location: clearwater, fla
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Well , the same thing happened to us today. Returning to KCLW, we had to divert to X39 because the runway was closed. It was mid-afternoon and hot. We waited an hour, got the all clear, jumped in the airplane and took off. A run up would have helped. Anyway the engine quit right after applying full power and we had a strong gas smell. We got off the runway, checked everything, did a full run up, everything was still green, and took off. We climbed out ok. The engine ran a little rough at 5000 rpm but as soon as we went up to 5400 rpm, everything smoothed out. We did not have any problems in the pattern, throttling back was smooth and the engine was smooth during taxi at low rpm, with no fuel smell. So, vapor lock or the start of a float problem, or maybe both. The float checks have been fine so far. We have 85 hours on the plane.
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  #8  
Old 04-25-2015, 08:52 PM
cactusman cactusman is offline
 
Join Date: Oct 2012
Posts: 421
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A couple of further points - a lot has been made about using winter formulation auto gas when the temps warm up....

(see http://www.vansairforce.com/community/showpost.php?p=545927&postcount=19)...amongst others....

(older article, but interesting none the less...)

http://www.eia.gov/todayinenergy/detail.cfm?id=11031

Also I was draining my tank thru the gascolator and noticed low flow - there was some debris on the gascolator screen (I mean how many times have I had to tear apart that tank now...despite my best efforts at cleaning up everything multiple times with everything from a microvac to duct tape). So cleaned the screen and re-wired the gascolator and the flow improved substantially...food for thought.

Last edited by cactusman : 04-25-2015 at 09:05 PM.
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  #9  
Old 04-26-2015, 05:20 PM
rgmwa rgmwa is offline
 
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Location: Perth, Western Australia
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Quote:
Originally Posted by cactuspilot View Post
So cleaned the screen and re-wired the gascolator and the flow improved substantially...food for thought.
I know this will sound like a dumb question, but how do you clean a gascolator screen? I checked mine recently and luckily it looked fine, but I couldn't see any easy way to remove it for cleaning - assuming you're supposed to remove it that is, or is there some other trick to it?
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  #10  
Old 04-26-2015, 05:36 PM
DHeal DHeal is offline
 
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Location: Windsor, California
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I couldn't figure out an easy way to remove the screen without compromising it's sealing function, so I ordered a few extra screens from Van's and just replace it with a new one if needed.
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