Extra 300 Engine stoppage
Thread Starter
Joined: Sep 2007
Posts: 103
Likes: 0
From: Hong Kong
Extra 300 Engine stoppage
We'll that got your attention so let me explain. The engine is good as gold in the air but has a nasty habit on the ground (when hot at sortie end) of dying when you advance the throttle from idle.
Someone suggested a "rich cut" so I have tried leaning back on the ground but now and again it will still do it. For context yesterdays cut was after 1 hour of flying... temps and pressures in mid green. A long runway backtrack then at idle for 20 or 30 secs as I negotiated a tight entry through hangar gates and then back on the throttle to a nice soft stoppage... just as if i had pulled the mixture...
Most odd, though no doubt the experts will educate me!
Someone suggested a "rich cut" so I have tried leaning back on the ground but now and again it will still do it. For context yesterdays cut was after 1 hour of flying... temps and pressures in mid green. A long runway backtrack then at idle for 20 or 30 secs as I negotiated a tight entry through hangar gates and then back on the throttle to a nice soft stoppage... just as if i had pulled the mixture...
Most odd, though no doubt the experts will educate me!
Joined: Jun 2002
Posts: 630
Likes: 2
From: UK
It may be that the idle mixture is incorrectly set: injected Lycomings should 'kick' only about 10 rpm when you slowly take the mixture control towards idle cut-off with the throttle at idle (625-650 rpm). This kick is when the mixture reaches the ideal stoichiometric ratio as it passes towards ICO. This should be checked with the engine at operating temp - ie post flight.
Being in HK, it may also be the fuel vaporising in the injector lines through heat soaking as they sit above the cylinders. Normally this would result in uneven running below 1500rpm as well.
Being in HK, it may also be the fuel vaporising in the injector lines through heat soaking as they sit above the cylinders. Normally this would result in uneven running below 1500rpm as well.
Thread Starter
Joined: Sep 2007
Posts: 103
Likes: 0
From: Hong Kong
Back again... and this time the title is pretty apt....
So I'm running on wing tanks (plenty of fuel in them - around 25 L) straight and level on a very hot day (90 degrees) and I get what appears to be fuel starvation, surging and power loss and nearly an engine stoppage (it felt like that).
Had already done 30 mins of a sortie and aeros on a mix of front and wings with no issue. When I lost power, i had been on wings for a good 5 to 10 mins, power set at 24/25 leaned and straight and level no yaw...
back onto front and pump and after a bit of surging and fluffing all was good, but damn it got my attention.
On landing there was plenty of fuel in the wing tanks and it fed on the ground run from them.
So a question, has anyone heard of vapour lock from the wing tank feed during extreme temps?
So I'm running on wing tanks (plenty of fuel in them - around 25 L) straight and level on a very hot day (90 degrees) and I get what appears to be fuel starvation, surging and power loss and nearly an engine stoppage (it felt like that).
Had already done 30 mins of a sortie and aeros on a mix of front and wings with no issue. When I lost power, i had been on wings for a good 5 to 10 mins, power set at 24/25 leaned and straight and level no yaw...
back onto front and pump and after a bit of surging and fluffing all was good, but damn it got my attention.
On landing there was plenty of fuel in the wing tanks and it fed on the ground run from them.
So a question, has anyone heard of vapour lock from the wing tank feed during extreme temps?
Joined: Oct 2007
Posts: 582
Likes: 6
From: Near EGSS
25 Litres is only 12.5 a side. The Extra tanks are very flat and the wing tank feed is prone to sucking air at low fuel levels. The fuel will easily drain from one side to the other and any slight bank or side slip will uncover the feed on the upwing side causing the symptoms you describe. The same thing can happen in a descent when the fuel moves to the front of the tank. It has happened to me several times. This is why the POH says centre tank for T/O and landing.The ground problem is almost certainly due to vaporisation in the injector pipes which are sitting on top of hot cylinders with low cooling flow. It can also happen on hot days on the second flight when the fuel has had time to heat soak on top of a hot engine.
Thread Starter
Joined: Sep 2007
Posts: 103
Likes: 0
From: Hong Kong
So Extra Experts... on the right side rear seat is the jacks for the headset as well as, in ours, a hardwire plug for Bose headsets. At the bottom is a data port.
Then at the top are two buttons marked "user" and "mark"... i guess i should know what these are but i dont.. cant find them in poh, supplements or anywhere else..
Come on .. give us a clue!
Then at the top are two buttons marked "user" and "mark"... i guess i should know what these are but i dont.. cant find them in poh, supplements or anywhere else..
Come on .. give us a clue!
