912S shutdown on Final

[kmach]

Has anyone had problems with fuel loading up and shutting down with a 912S ? I was on a long final with low rpm and just before touchdown it died, landed smooth rolled out and restarted without difficulty . I am a little concerned, any comments or is the key to clear the engine at regular intervals ?

[Agfoxflyer]

Five or so years ago there was an incident where a Model 4 (I think) was on a long decent with just a few gallons of fuel in the tanks. All the fuel migrated to the front of the tank and the fuel intake unported. The plane went down on a road with substantial damage. Could this be the situation? If I remember correctly the fuel on the plane was close to minimums. My brother use to have a C140 and it unported on take off twice with half tank.

[Dorsal]

out of curiosity what constitutes low RPM?

[Slyfox]

do you have a low fuel warn. If not, get it.

[napierm]

Seriously though, besides fuel level and/or pressure, could your idle mixture be set too rich? The prop windmilling with the throttles closed will make the idle circuit to run a little richer than it would on the ground. That can cause the plugs to load up.

Just a thought.

[kmach]

do you have a low fuel warn. If not, get it.

I was test flying a plane that was for sale and yes it has a low fuel warning light. we checked tanks before flight and had over half tanks, low ceiling so we were doing stop and goes , I was pretty high on a short base and on final had the throttle pulled right back. l was concetrateing on the slip characteristics and not the rpm, maybe a little too much , so I don't really know what the rpm was , I think the carb idle stops were set a little low on this plane. and I slipped in, just at flare -to touchdown engine quit, rolled out and stopped then it fired right back up with no real difficulty. I am thinking it pooled up with fuel as I did not clear the engine or move it off idle for some time,and as well we had the aux fuel pump on.

[Dorsal]

Unless you over pressure the fuel system the carb floats prevent excess fuel. I have only 6-7 hours on my 7 but I have noticed as I set the throttle on short final to 1800-200 rpm that by the time I'm rolling off the runway it is closer to 1400-1500. I was actually warned by CDE2fly to watch for killing the engine on final, not sure if that was just meant as a new engine thing or in general. I think you may be right to check the idle stops.

[DesertFox4]

Sounds like idle set a little low.

[Av8r3400]

Mine actually quit this last week on roll out on the UL field at Airventure. My problem is the idle was set too low and I didn't catch it in time...

These motors need to have ~1800 rpm to sustain a good idle. I have mine set a little lower to aid decent. I have never had any issue on decent with the prop windmilling, just after touchdown when the rpm drops too low.

[Slyfox]

Gee, I have my idle set at 500, you got it, and get this, I always pull back on the throttle for a nice short landing. I do set the idle back up as I flare for landing, but sometimes my idle will go down to 1000 and run just so sweet. I do set it back up to 1800 idle, but I have to say I never I repeat never have had the engine quit. I say if the idle is low and you have a problem with the engine quiting, than you better check the balance of the carbs. I don't mean idle stop either, I mean cable to cable, left carb to right carb. I would go into the carbs and make sure they are nice and clean and the orings are in prestine condition, Oh and don't forget about the carb sockets, a little crack in those things and all bets are off on things.

Also remove the spark plugs, any wetness and the 912 series doesn't run for anything, maybe on higher idle, but idle, forget it.