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CharleyB

I'm New Here
I've had ongoing fuel vapor lock problems with my AFP injected 0-320 RV-6A. AFP recommended a fuel pump shroud. Aircraft Spruce offers a shroud advertised for Lycoming fuel pumps. The product looks good in the catalog, but I wonder about installation problems. Does anybody have any experience with it.

Charlie Brame
RV-6A N11CB
 
Yes, I currently have one on both my 10 and my 7. They aren't fun to install if the engine is already on the airplane, which sounds like yours is, but it is doable. I ran a duct with scat tube from the front baffling.

Vic
 
Purge Valve?

CharleyB said:
I've had ongoing fuel vapor lock problems with my AFP injected 0-320 RV-6A. AFP recommended a fuel pump shroud. Aircraft Spruce offers a shroud advertised for Lycoming fuel pumps. The product looks good in the catalog, but I wonder about installation problems. Does anybody have any experience with it.

Charlie Brame
RV-6A N11CB
Click to expand...

Do you have a purge valve? I have been running AFP FI for a couple of years now and have never experienced any vapor lock problems. I consider the purge valve a requirement in TX, even had one on my carb'd version before I switched to FI. Without it you are definately subject to VL on a hot short turn.
 
FI purge valve

I do have a purge valve and regularly use it. I have few problems starting a hot engine after purging. My vapor lock problems show up after landing from a flight, and while taxiing out after a hot start.

Charlie
 
Charlie,
Have any photos of your engine compartment, in particular hose routing?
 
What you are likely experiencing is fuel boiling in the injector lines, it does cause some stumbling in the situation desribed but this is not the same as vapor lock. I went through the same thing the first summer after I installed the FI. After lengthy checking and trouble shooting Don and I both concluded it was just the typical hot operation and was "normal". Don recommended trying a smaller .025 injector as that would help to raise the pressure in the injector line just a bit, it did help but did not eliminate it. The only thing when using the smaller .025 nozzle is to verify fuel flow and EGT are still good at max power which mine was. You need good fuel pressure to feed the smaller nozzles, I ajusted my weldon aux pump to run 30psi to help maintain full pressure at TO power. The smaller nozzles also helped with LOP operation.
 
Charlie, my RV-10 does the same thing. Don sent me a new main jet one size smaller, as I was running about 300 degrees between full rich and lean during cruise. I just installed the jet this week end, and have only made one flight, which didn't require the land, fuel, and taxi, but it did seem improved when I taxiid in from the flight. I also adjusted the main mixture adjust mechanism about 1 flat richer as well, and now a I get a very good 50-60 rpm rise when leaning for shutdown at idle at around 700 rpm's.
So, do check your full rich to lean spread with your EGT's, and check your idle adjust.
I will let you know if I continue to see improvement.

Vic
 
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