OS 61FX Engine Problem
 

I'm flying my Airmadillo trainer with an OS .61FX Engine. I followed all instructions for break in and have mounted it on the plane. Every time I fly the plane the engine runs good on the runup but when it gets into the air (usually almost immediately after takeoff) the engine dies resulting in a deadstick landing (fortunately it's an Airmadillo). If I hold the plane at full throttle on the ground for an extended period of time (approximately 35 seconds) it sometimes dies also. When it quits on the ground there is still fuel in the fuel line, so it's not fuel starvation. It also has lots of air bubbles in the line at times which makes it run rough. Can a guy put a piece of foam in the tank to cut down on the bubbles like they do on the RC cars??? If so, what kind of foam should be used and where can you get it??? I'm using the muffler pressure fitting with a line to the tank. Is this correct with the 61FX??? And finally, I'm using a fox glowplug with an idle bar. Is this necessary or correct???

Any help or suggestions would be greatly appreciated.

Bill Britton
Kansasflyboy

RE: OS 61FX Engine Problem
 

Try putting the foam outside the tank to isolate the vibration. Check the fuel line carefully for pinholes, and richen the mixture somewhat to stop the deadsticks.

RE: OS 61FX Engine Problem
 

Also switch to an OS 8 glow plug. I have 2 of these engines, and so long as the tank is properly isolated from vibration, bubbles in the line are not a problem. The OS 8 is a hot plug and will sustain a very smooth idle. Like henry* said, check the lines for holes and richen the mix a bit also.

RE: OS 61FX Engine Problem
 

Do what Primodus and henryhighwood said, especially wrapping the tank in foam.

In addition, make sure that while on the ground, advance the throttle to full, then pick up the plane and hold it's nose up AT LEAST to a 45 degree angle (90 is better) for about 30 seconds. If the engine changes rpm, your low end is off.

If it still dies on you after all this, replace ALL the fuel lines including the ones in the tank. This would indicate a pin hole somewhere in the line.

RE: OS 61FX Engine Problem
 

Bill there shouldn't be any air bubbles in the fuel line between the carb and the needle at all when the engine is running if this is so replace the fuel line and try again also double check the fittings as well. as far as break in mine was a biatch to break in it ran great on the ground nose up check fine ,take of and the engine would stall so now i run it a little fat until it breaks in good luck Bill

RE: OS 61FX Engine Problem
 

You have good info here. I just want to add, it sounds to mee that the LOW end is lean. You run on the low speed needle until around 2/3 throttle. I would adjust the low spped needle out maybe an 1/8th turn at a time untill you get the mixture right. Do it with the engine off and after adjusting clear the engine at full throttle for a few seconds to clear it out and check it then. Good luck.

Mark Shuman

RE: OS 61FX Engine Problem
 

Thanks for all the info guys. I'll try some of these ideas this weekend hopefully. I'll let you know of the results.

Thanks again,
Bill Britton

RE: OS 61FX Engine Problem
 

Same Problem Here, Balance the prop! That fixed it. I Bought a smaller tank and installed it too and put retainer clips on all the fuel lines including inside the tank. I put foam around the tank and that helped some. But balancing the prop is the key. I can run full throttle with no foam now.

Tim

http://www.airmadillo40.com