Clean your Sniffle Valve recently?

[wcalvert]

Doing a condition inspection I decided to pull my sniffle valve for inspection (IO-360/Superior intake,300 hours). This part always seemed like a witch doctor fix looking for a problem ...

Once it was out, I gave it a shake, and no rattle. Blew some air through it and it was completely plugged. So next I shot some auto fuel injector sensor cleaner through it, and voila, the insides now rattle and it's again a check valve.

So somewhere along the way this thing stopped sniffling fuel, but I didn't notice.

You might toss this into your inspection list, you never know

 

[hgerhardt]

And how much liquid came out of the plenum when you removed that valve? I'm guessing less than a teaspoon.

 

[Bavafa]

Is this really a safety issue? Even if it is plugged, there is no adverse safety since many many planes don't install one and the hole is plugged.

To test it, instead of pulling it out, run your electric pump for a few seconds on the ground with the engine turned off. If fuel is not dripping out, then there is a problem somewhere.

 

[vic syracuse]

Is this really a safety issue? Even if it is plugged, there is no adverse safety since many many planes don't install one and the hole is plugged.

To test it, instead of pulling it out, run your electric pump for a few seconds on the ground with the engine turned off. If fuel is not dripping out, then there is a problem somewhere.

There is a potential for the intake to get full of water if it sits during a heavy rain and has one of the snorkel intakes like on the RV-8. On startup a nice slug of water could cause a hydraulic lock.

It is a good idea to both have them installed and check them once in a while.

Vic

 

[Jetmart]

They can stick open as well.
I check mine annually.

 

[Bavafa]

It is a good idea to both have them installed and check them once in a while.

Vic

A good idea indeed. All three planes I have built have had sniffle valve but it is also a good idea to drill a small hole at the bottom of the snorkel to prevent what you just said.

It is also a good idea to check the condition of the air filter if it rains that hard. your engine will not suck nearly as much air as it needs and may even suck some water from the soaked air filter.

 

[Tankerpilot75]

Bill,

Where is your sniffle valve located on your Superior IO 360? I was checking the superior overhaul manual and couldn’t locate it.

 

[wcalvert]

... and from the top

"how much liquid came out of the plenum when you removed that valve?"

None

"it is also a good idea to drill a small hole at the bottom of the snorkel"

Have that

"Where is your sniffle valve located on your Superior IO 360?"

At the bottom, near the lowest part of the intake manifold

.

 

[bjdecker]

Is this really a safety issue? Even if it is plugged, there is no adverse safety since many many planes don't install one and the hole is plugged.

To test it, instead of pulling it out, run your electric pump for a few seconds on the ground with the engine turned off. If fuel is not dripping out, then there is a problem somewhere.

...and the mixture needs to be full rich, and the throttle full open....

then you'll get some dribbling out of the sniffle line...

 

[Desert Rat]

This is my first experience with a sniffle valve. I get the concept, but for my future reference, if you want to check it at annual do you have to take it out and shake it or is there a way to check it in place?

Would there be anything wrong with shooting a puff of air up in the drain line and listening for the rattle? I would expect that if it's loose then something like a turkey baster would be all thats needed...

 

[calpilot]

Doing a condition inspection I decided to pull my sniffle valve for inspection (IO-360/Superior intake,300 hours). This part always seemed like a witch doctor fix looking for a problem ...

Once it was out, I gave it a shake, and no rattle. Blew some air through it and it was completely plugged. So next I shot some auto fuel injector sensor cleaner through it, and voila, the insides now rattle and it's again a check valve.

So somewhere along the way this thing stopped sniffling fuel, but I didn't notice.

You might toss this into your inspection list, you never know

For the taildraggers, the sniffle valve is about worthless, as it takes a lot of overprime to drip out the valve due to the deck angle of the sump. I just put a plug in it! There have been a lot of people, myself included, having a surging engine when hot during taxi. It was coused by the sniffle valve opening and closing depending on the manifld pressure at an idle. Bottom line, dont overprime! There is a cold start, hot start, and flooded start, the latter is usually due to improper technique. Enjo the San Juans!
DAR Gary

 

[wcalvert]

I'll agree that the sniffle valve on a tail wheel craft is not very useful. On the -7, you can't access the most aft port on the intake manifold because of the conflict with the exhaust pipe, so the lower sump area would need to have a lot of fuel there to actually drain.