First Time Engine Run

[Ak360]

Any suggestions on priming the Rotax 912 fuel for first run. Without an electric fuel pump or primer this seems like it might prove difficult and I am looking for some suggestions.

[Dave S]

AK,

Not a problem.

A few ideas.....

Consider the there may be enough head pressure from the wing tanks to overcome the check valves (check valve springs are extremely light) in the mechanical pump and the system may fill up anyway.

If the fuel system has gas in it when you loaded oil and primed the oil pump, you would have rotated the prop enough to more than assure gas is present at the carbs, provided the fuel valve was open.

While doing the rotax burp when checking the oil prior to startup, the prop likely is rotated enough to deliver fuel to the carbs.

Once you start cranking to start, the fuel pump will have quite a few strokes to pressurize the system.

I recall that I disconnected the fuel hose at the pump and opened the fuel valve for flow testing anyway before first start and that resulted in gas being right at the mechanical pump and the engine started after a very few revolutions.

Sincerely,

Dave S
KF7 Trigear
912ULS, Warp Drive

[Ak360]

Thanks. That is reassuring. I wasn't sure how big of deal it was going to be without a manual primer or electric fuel pump.

[SkySteve]

AK360,
I do have a primer installed on my 912A (80hp) and I usually give 3 to 4 pumps when cold. Engine starts right up within 1 to 2 seconds.

[Dorsal]

I started mine initially from the header tank alone (below the pump and carbs), no priming at all. Cranked twice for 4-5 sec and she roared to life