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3 Answers

Carburetor fire upon startup

Asked by: 6828 views , , , ,
Aircraft Systems, General Aviation, Weather

I went to take a friend flying today in a 1966 cessna 150F. We live in North Dakota, and since it being colder around this time of year, today was a nice day at 34F. After getting fuel, preflighting the aircraft and a short brief we got into the plane to fly around for a couple hours. Upon starting the engine, I did as follows, mixture full rich, throttle, ⅛inch, and primed it 8 times.(left it charged) Turned the key to both and pressed the start button, she turned over as normal and (here I pushed in the primer) fired a for a short couple seconds then quit. I then let it sit for around 3 minutes before attempting another start. This time left throttle out, mixture out with primer charged and turned it over and pushed in the primer as it was turning over. At this time we heard a weird sound, so I quit cranking and shut everything off. I thought it be good to have a mechanic look at it after a sound like that, after exiting the aircraft and upon tying it down, my friend walked to the front of the plane and said there was flames coming from the carburetor. We quickly extinguished the flames. After this experience being a young pilot at 17 with 65 hours, I need someone to critique  what I did wrong...I followed my cold weather engine starting to a T. Any advice at all is appreciated. Thanks.

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3 Answers



  1. Brian on Nov 30, 2015

    Most carburetor engines will start, as cold as 10 degrees F (minus 8 C), with 3-4 pumps of the throttle, throttle idle, and immediately crank. Long and short of it is pilots don’t know how to start engines. If you don’t believe me, sit outside a mechanics shop for a few weeks and listen as they start every plane in a few swipes of the prop and a low rumbling idle 99.9 times out of a 100.

    To make matters worse, every PoH has a different cold weather procedure. And, more often than not, their procedures don’t exactly match the engine manufacturers procedures. This is especially true for older aircraft as most of them have newer engines by now. My suggestion to you is to go and speak with your mechanic about it and ask them to demonstrate a few starting techniques. Even better if you can befriend one and get them to hop in with you a few times for a quick 1 minute starting demo on those colder days.

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  2. Brian on Nov 30, 2015

    +10 f = -12 C my apologies.

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  3. Best Answer


    Nibake on Dec 07, 2015

    Hi Austin. I assume you are talking about 3528L. I don’t think you should every need more than 4-5 strokes of primer even in the coldest weather, assuming that each stroke is getting a healthy amount and not just dry. Having said that, the only explanation for a carburetor fire is that the fuel ran back down the intake manifold to the carb. This assumes that you DID NOT pump the throttle, if you pump the throttle you will be much more likely to have a carb fire so that is something you don’t want to do since you have a primer. I’m not sure about everything that happened, but here are a couple things you could take away from the experience: when you prime, be ready to crank, try to let as little time as possible pass between priming and cranking and second, most important, if you suspect a carburetor fire KEEP CRANKING! Hopefully you can get the engine to start, even if you can’t, keep cranking to draw the flames up toward the engine. Happy flying and congrats on getting your ppl!

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