If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
|
#1
|
|||
|
|||
Starting Engine Question (O-320, Warrior)
My question refers to Warrior IIs, but could be about other
Lycoming O-320 and O-360 engines with electric fuel pumps too. I've noticed checklists on some Warriors tell you to turn the electric fuel pump ON and leave it on for starting, and others tell you to turn the fuel pump ON, check pressure, then OFF before starting. The actual P.O.H. I've seen says to turn the fuel pump on before start but doesn't even mention to check the fuel pressure to make sure that the electric pump works. It doesn't say when to turn the fuel pump off, except during the run-up to turn it off so the pressure can be checked. All in all, the checklists in the actual P.O.H. aren't very impressive and seem to leave a lot of important stuff out. They don't even remind you to shut off the cabin heat/defrost before starting to protect you in case there is a fire during start. So why the different schools of thought? It doesn't seem necessary to leave the pump on for taxi, as the POH suggests. But should the fuel pump be on while cranking? What does everybody do? |
#2
|
|||
|
|||
Pump off - Throttle Full Open - Mixture Full Rich
Pump on (for 4 sec) then Pump Off Throttle 1/2" - Mixture Idle Cut Off Crank Mixture Fully Rich when engine fires (and starts to run) "Lisa" wrote in message ... My question refers to Warrior IIs, but could be about other Lycoming O-320 and O-360 engines with electric fuel pumps too. I've noticed checklists on some Warriors tell you to turn the electric fuel pump ON and leave it on for starting, and others tell you to turn the fuel pump ON, check pressure, then OFF before starting. The actual P.O.H. I've seen says to turn the fuel pump on before start but doesn't even mention to check the fuel pressure to make sure that the electric pump works. It doesn't say when to turn the fuel pump off, except during the run-up to turn it off so the pressure can be checked. All in all, the checklists in the actual P.O.H. aren't very impressive and seem to leave a lot of important stuff out. They don't even remind you to shut off the cabin heat/defrost before starting to protect you in case there is a fire during start. So why the different schools of thought? It doesn't seem necessary to leave the pump on for taxi, as the POH suggests. But should the fuel pump be on while cranking? What does everybody do? |
#3
|
|||
|
|||
Cockpit Colin wrote: Pump off - Throttle Full Open - Mixture Full Rich Pump on (for 4 sec) then Pump Off Throttle 1/2" - Mixture Idle Cut Off Crank Mixture Fully Rich when engine fires (and starts to run) Is that the procedure in your POH? Except for the throttle setting, your description most closely matches the Starting Engine when Flooded procedure in my POH. The normal cold & warm starts don't include cranking with Mixture at Cut-Off. |
#4
|
|||
|
|||
This sounds like the procedure for a fuel injected engine.
The fuel pump in the carbureted engine has no effect on engine starting except to make sure that about three pounds of fuel pressure is obtained at the carb inlet. This is a pressure regulated pump and will stop pumping when the set pressure is reached. The method in the manual usually is the best. Good luck, Skyking "Lisa" wrote in message ... Cockpit Colin wrote: Pump off - Throttle Full Open - Mixture Full Rich Pump on (for 4 sec) then Pump Off Throttle 1/2" - Mixture Idle Cut Off Crank Mixture Fully Rich when engine fires (and starts to run) Is that the procedure in your POH? Except for the throttle setting, your description most closely matches the Starting Engine when Flooded procedure in my POH. The normal cold & warm starts don't include cranking with Mixture at Cut-Off. |
#5
|
|||
|
|||
Ah, sorry - I saw O-360 and thought IO-360 for some strange reason.
|
#6
|
|||
|
|||
For a carburetor engine the electric fuel pump is only needed to fill the
bowl before cranking... The check list you give is for fuel injected engines... denny "Cockpit Colin" wrote in message ... Pump off - Throttle Full Open - Mixture Full Rich Pump on (for 4 sec) then Pump Off Throttle 1/2" - Mixture Idle Cut Off Crank Mixture Fully Rich when engine fires (and starts to run) |
#7
|
|||
|
|||
Hi Lisa,
You should have the electric fuel pump on for start up. Then shut it off right after start up to check for normal pressure from the engine driven pump as you check for the oil pressure once the engine is idling at about 1000 rpm. The next time I turn the electric pump back on is when I take the active runway for departure. Hope this helps. David Smith "Lisa" wrote in message ... My question refers to Warrior IIs, but could be about other Lycoming O-320 and O-360 engines with electric fuel pumps too. I've noticed checklists on some Warriors tell you to turn the electric fuel pump ON and leave it on for starting, and others tell you to turn the fuel pump ON, check pressure, then OFF before starting. The actual P.O.H. I've seen says to turn the fuel pump on before start but doesn't even mention to check the fuel pressure to make sure that the electric pump works. It doesn't say when to turn the fuel pump off, except during the run-up to turn it off so the pressure can be checked. All in all, the checklists in the actual P.O.H. aren't very impressive and seem to leave a lot of important stuff out. They don't even remind you to shut off the cabin heat/defrost before starting to protect you in case there is a fire during start. So why the different schools of thought? It doesn't seem necessary to leave the pump on for taxi, as the POH suggests. But should the fuel pump be on while cranking? What does everybody do? |
#8
|
|||
|
|||
Hi Lisa.
I agree that the actual POH leaves a lot to be desired. We check for pressure from the electric fuel pump during preflight. Master ON, Check Fuel Gauges, Fuel Pump ON, check pressure, Fuel Pump OFF, Master OFF. We do use the auxilliary fuel pump for starting the engine - don't remember now why exactly, but I believe it's just to ensure fuel flow during the start. Cranking the engine w/o enough fuel (too lean) is worse than getting it started and then having it kill when the aux pump is turned off. Less risk of detonation on startup, I guess (and I am guessing). Once the engine is started. we do not use the auxiliary pump again until pretakeoff (it is off for taxiing and the runup). It stays on through takeoff until 500' AGL. Thinking about your comment about shutting off cabin heat/defrost before starting, I could see this being an issue in airplanes where the carburetor is mounted underneath the engine, as flames could travel up into the cabin air duct. The way the carburetor is mounted on the Warrior's engine, I think this is far less likely to happen. I won't say it couldn't, but I just don't see how, unless you had a ruptured fuel line that covered the inside of the cowling - something that would create a larger fireball than just a flooded carburetor. "Lisa" wrote in message ... My question refers to Warrior IIs, but could be about other Lycoming O-320 and O-360 engines with electric fuel pumps too. I've noticed checklists on some Warriors tell you to turn the electric fuel pump ON and leave it on for starting, and others tell you to turn the fuel pump ON, check pressure, then OFF before starting. The actual P.O.H. I've seen says to turn the fuel pump on before start but doesn't even mention to check the fuel pressure to make sure that the electric pump works. It doesn't say when to turn the fuel pump off, except during the run-up to turn it off so the pressure can be checked. All in all, the checklists in the actual P.O.H. aren't very impressive and seem to leave a lot of important stuff out. They don't even remind you to shut off the cabin heat/defrost before starting to protect you in case there is a fire during start. So why the different schools of thought? It doesn't seem necessary to leave the pump on for taxi, as the POH suggests. But should the fuel pump be on while cranking? What does everybody do? |
#9
|
|||
|
|||
"Chris Hoffmann" wrote in message ...
Thinking about your comment about shutting off cabin heat/defrost before starting, I could see this being an issue in airplanes where the carburetor is mounted underneath the engine, as flames could travel up into the cabin air duct. The way the carburetor is mounted on the Warrior's engine, I think this is far less likely to happen. OK, I'll bite. Where exactly is the carb mounted on your Warrior? I don't think I've seen a carburated, horizontally opposed aircraft engine that didn't have the carb mounted on the bottom. I'm sure there may be a few, but they're not common. John Galban=====N4BQ (PA28-180) |
#10
|
|||
|
|||
John Galban wrote: OK, I'll bite. Where exactly is the carb mounted on your Warrior? I don't think I've seen a carburated, horizontally opposed aircraft engine that didn't have the carb mounted on the bottom. I'm sure there may be a few, but they're not common. Many Lycomings have it behind the engine. George Patterson Treason is ne'er successful, Sir; what then be the reason? Why, if treason be successful, Sir, then none dare call it treason. |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Real stats on engine failures? | Captain Wubba | Piloting | 127 | December 8th 03 04:09 PM |
Rear engine in a crash question | BernadetteTS | Home Built | 17 | November 24th 03 04:10 AM |
Tecumseh Engine Mounting Question | jlauer | Home Built | 7 | November 16th 03 01:51 AM |
1710 allison v-12 engine WWII p 38 engine | Holger Stephan | Home Built | 9 | August 21st 03 08:53 AM |
Gasflow of VW engine | Veeduber | Home Built | 4 | July 14th 03 08:06 AM |