Welcome Guest. Sign in or Signup

2 Answers

Fuel flow during priming for engine start.

Asked by: 2117 views Aircraft Systems, Commercial Pilot, Flight Instructor, General Aviation, Private Pilot, Student Pilot

Good evening everyone,

 

This might be a sily question for you all but I became curious with engine priming and its fuel flow.

 

So when we prime the engine for start up(referring to C172S), we turn on the master and aux fuel pump and introduce mixture for few seconds and back to idle. Now the fuel after flowing throught the aux fuel pump, it flows down the linings of fuel system tomthe engine driven pump which is not working because engine is not running.

So my question is, does fuel still go through engine driven fuel pump, if not how does fuel enter cylinders for successful start up ?

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

2 Answers



  1. EAD on May 05, 2016

    I would suggest reading Section 7 of the POH or Information Manual for the aircraft. They have a complete explanation and diagram of fuel flow.

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes



  2. crossaint on Sep 12, 2016

    The main fuel pump is of the diaphragm type, with an input and output check valve that prevent fuel flowing backwards to the tanks. These can easily pushed open by the auxiliary fuel pump.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.