Engine suddenly quits running ?????

[kevin814]

I have a Jabiru 3300 in my Sonex, but I had similar issues. Mine was due to vapor lock, and needing to richen the idle mixture slightly (Rotec). I had issues after landing when hot, it would quit on me several times before I could get back to the hangar, very frustrating. I added insulation around the Rotec, which helped, now I just get the occasional burp.

I found than when the engine is hot, and during ground running, you arent flowing much fuel through the fuel system. What is in your lines has more time to pick up heat and vapor lock. I never had an issue during flight or take off, since the fuel flow was quite a bit higher. To avoid vapor lock during 20-30 minutes of ground running would take a tremendous amount of insulating, and may not be necessary in my humble opinion.

Regards,

Kevin K.

[Sonex541]

Ok here goes I will try to answer all the .? In one reply I hope lol ,
Revmaster 2100 with a revflow carb , it has the warm air tube and air filter , which blocks off the outside air and uses the warm cowl air diverveted thru the k&n filter , bought with 40+ hours , currently 100 hours , I had a issue years ago with me using 2 gallons of regular fuel and it caused the inside of the , fuel line from the gas collator to revflow to become swollen and wouldn't flow enuff fuel to run wide open throttle , that was around 42 hours and when I first bought , I rebuilt the revflow and cleaned gas collator and put new fuel lines , been running like a top , put on 60 + hours no issues , regular maintenace oil changes and filter , valve adjustment , spark plugs , clean fuel filter , I'm very strict on maintence , ,soo I had some time were I was unable to fly due to work , so I slide the cylinders out , re sealed and put back , torque heads, valve adjment , the whole deal , I ran it for 20 min at different rpms , with no cowl. Checking for leaks , and then I could re tighten clamps, bolts, screws , etc ,etc, , put cowl on and ran to make sure every thing 100 % it dies out , about 15 min into it , I have never let this run before or since I owned it for more than 5 minutes with the cowl on , we taxi , run up test , hit the runway and take off , a few times it has stalled while waitin to take off , due to running rich and chocking up , that's all , the temps are a bit hotter with the cowl as excepted cht mostly , egt are pretty close with cowl on and with cowl off , I'm stumped really bad , my friend says your not getting any airflow over the entire engine , things are getting hot, fly the thing around the pattern and see , well I'm scared lol plane and simple , dam right I'm scared , especially when it dies so dam quick no sputtering , nothing , just like turning the key off , lol Sorry for the long story , but you guys are the most knowledgable when it comes to Sonex ,

[radfordc]

The good news is if it is a hot fuel problem you will know when you have it fixed. Wrap all the fuel lines with foam pipe wrap insulation and then wrap the insulation with aluminum tape. Also make a heat shield for the gascolator. I used a piece of flat foam and wrapped the foam with more aluminum tape and then tied wrapped the heat shield around the gascolator.

If you can now run the engine with the cowl on for more than 10 min's you know you have it.

But why would that suddenly be an issue now, after 100 hours of flight time? I'm not sure I buy it.

Mike Smith

Whether you "buy it" or not it's certainly an easy thing to try. For a few dollars worth of foam and tape you can find out.

Why does it run perfect without the cowl, but dies with the cowl? Sounds like a heat problem to me.

[Sonex541]

Made a run to home depot aviation dept, and bought some foam ,aluminum tape , and wrapped it all up , even the gascolater , tommorow we will find out the truth , and I will report my findings ,

[fastj22]

You say you've had the sonex for a few years. Is this the first time you have tried extended cowl on ground runs in June (summer temps?)? Or the first time you ever did extended cowl on ground runs? Me thinks the problem may have always been there lurking, but you just never exposed it until now.

[merle reppert]

You need a burp tube ---Merle reppert

[jaywa]

To support the actions taken - I have a 2300 Revmaster and had similar problems until I insulated fuel lines , plus added reflective paper on top , AND I converted to Avgas ( much lower vapor pressure = less likely to vaporise at high fuel temps and low fuel pressure ).

Also run lean during taxi and in the glide ( including finals ) because I had a lot of plug fowling in the taxi and engine spluttering on landing due to engine flooding.

[Sonex541]

I started flying this in oct and nov ,lasy year and the air was cool I did do a few ground run ups for a few min , and no issues , I insulated all the fuel lines and gascolator and didn't have time yesterday to do some testing , but today I am goin to take a trip to airport to do some ASAP , I too think the problem has been there , but never has happened ,

[Sonex541]

Well I wrapped and insulated the fuel line and gascolator , put cowl on and 14 min later it burped once , and then I raised the rpms to about 1800 and it burped a few times and stalled once , , all the temps looked good , egt , cht , oil temp , I have no idea what to do with it , I refuse to take a chance flying this , I fly out of class d So it's pretty busy and no place to put it down in the event the engine quits I am ready to give up on it ,.....grrrrrrrrrrrrr, for sale best offer lol possibly ,

[vigilant104]

What type of fuel are you burning? How warm was it at your location today? Did you try to run it with the cowl off?

Are your exhaust pipes wrapped? That's another way to significantly reduce the temps under the cowl.

Before throwing in the towel, I'd first do what many others have done and eliminate the gascolator and get those pipes wrapped if they aren't already. And Merle's suggestion of adding a "burp tube" is one that some people have used to eliminate the burps.