Thread: engine stop in flight

I was flying at 4300 rpm 94 kts. I pushed the throttle full (which goes usually to 5100)and my engine stopped a moment (so did my heart) I came back to 4300 rpm and after a few sputter came back on life. I headed home and close to landing I tried again full throttle. Same thing happened. Once landed on the water I tried full throttle several times (without taking of) and everything was fine Any suggestion where to look

You didn't mention, but I take it you push the throttle steady and not fast to full throttle. (Not usually the problem.)
4300 rpm is pretty slow rpm for a 912ULS Rotax?
Before I mention any thing else, after its fixed I would set my WOT to 5500-5600 if you have a ground adjustable prop. With the extra float weight you will have better climb and over all performance.

Ok now to the fuel. If it were me I would drop the float bowls and check the fuel. Water or dirt might cause this??? Small amounts of water in the float bowl could easily cause this.
If you have a Dynon what is the fuel pressure? If you don't have a Dynon D120 then put a mechanical gage in line to double check the fuel pressure out of the fuel pump.

And last, but not least pneumatically sync the carbs even if you just did it 20 hrs. ago.

You need to try these items to rule them out unless you stumble on something obvious.

How many hours on the plane?

I appreciate the advice. Carbs have been sync pneumatically but will redo. Dynon did not indicate anything wrong on fuel pressure but my attention was not immediately there. I remember some warning of low fuel pressure last year while flying with flight design rep from Ukraine but he did not seem to bother. Will check carb bowl and fuel filter if accessible !!! seems to be hidden. Fuel drain is clean but high humidity at night could produce condensation. Now I wonder if I did not push the throttle to fast . But I do not think that I would have pushed it to fast three times in a row On the water I push it very progressively not to splash water on the propeller but I am not sure that I did not move it to fast in flight. Plane has barely 60 hours.

This sounds exactly like the problem we encountered. I suggest you turn off the fuel, clamp one of the fuel lines shut, put a gas can under the fuel drain and check the fuel flow on the Dynon fuel flow meter. It should be min of 11 gph. Unclamp and try the other side. Next replace the fuel screen located by the shut off valve with the new FD metal filter.
The ethanal in the fuel will collaps the plastic filter and restrict the fuel flow. Check out FDUSA web sight service bullitan
for details. Also check the gascolator screen.

This is 'a shot it the dark' -- check the balancing line between the carbs where it runs through the air box. We had a similar problem and spent days/hours in fuel system, carbs, connections, etc. We didn't discover the 'break in the line' until we started to remove the air box. Just a suggestion. Roger Lee has seen this (as I learned later) and may have a comment or two.
Good hunting,
Tony

Tom is right and I should have mentioned a fuel flow test. He gives a very good example and I should have given it more thought before I posted my answer, sorry.
It does sound like a fuel delivery problem.

Hi Tom,
Nice to have you around. We hope to hear more from you and looking forward to meeting you all at Page.

another thing to check. One time I slightly closed the fuel valve (over the keys). It wasn't obvious, and it idled fine. During the run-up, it stalled. A quick flow check found the problem, and off I went.

Depending on the cables, the fuel valve might not be completely open unless the handle is up against the stop.

It seem icy problem. I have ice at 7500 feet with 110 knots at 4800 rpm(i have constant speed) . I have to climb to 8500 and when i asked power my engines begins to sput sput. Than i open completely trottle and after some seconds all seems ok! My meccanics said ghiaccio! (ice!)

Fit a carb heat kit and never worry about it again ...I had engine out last year due to carb ice and was forced to land no damage or problem .Fitted heat kit no problem since ..

Cheers Mike

Carb heat kits.

There are two types. One connects to the coolant line and uses the hot coolant. The other is the electric version. If you are going to use one use the coolant version. It is the recommended one and it doesn't draw power from your system and you don't need to turn the coolant version on or off..