HopePilot Posted June 26, 2012 Report Share Posted June 26, 2012 The other day, after priming fuel pressure with the fuel pump, prior to startup, I noticed something dripping from possibly the larger of these tubes. It made a very small puddle, which appeared to be fuel, but I thought this was where oil escapes, but I've only got 7 qts. in there right now. Will fuel drip from this area if you over prime? Quote Link to comment Share on other sites More sharing options...
KSMooniac Posted June 26, 2012 Report Share Posted June 26, 2012 Are you talking about the tubes that exit the back of the cowl on the pilot's side? If yes, there is one tube from the breather outlet of the engine (oil can blow out here) and another from the bottom of the induction pan...which will drip fuel if you over-prime or flood the engine. BTW, many Lycomings will blow oil out if you fill to the 8 qt capacity. Many will blow it out if you put in more than 6, too. I generally fill to 6 qts for that reason. YMMV Quote Link to comment Share on other sites More sharing options...
HopePilot Posted June 26, 2012 Author Report Share Posted June 26, 2012 Yup that's what I was talking about. Thanks. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted June 26, 2012 Report Share Posted June 26, 2012 IIRC its called th "sniffle valve". It is supposed to close when engineis running or else it pops and backfires at idle. http://www.donmaxwell.com/publications/MAPA_TEXT/External_Hoses/External_Hoses_Tubes.htm Quote Link to comment Share on other sites More sharing options...
Piloto Posted June 26, 2012 Report Share Posted June 26, 2012 The dripping that you are seeing is perfectly normal after you prime the engine before start. It comes from the excess fuel injected into the cylinders that drains down via the intake pipes into the crankcase intake plenum at the bottom of the engine. At the bottom of the plenun/case there is small AN fiting with a hose that discharge this fuel by the left cowl flap opening. If the excess fuel is not drained backfiring can occur during engine start. José Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.