kerwin50

I have an new OS 61 FX on a 3D airplane and at 1/8 to 1/4 throttle setting if the engine set at the setting for a minute or 2 in flight it will die. Above 1/2 throttle the engine preforms flawlessly.
I had to change the glow plug once already and the engine hasn't had a Gal of gas through it yet.
When the glow plug died I richend the idle mixture screw to the point that there is just a slight hesiatation. I was running wildcat 15 % then switched to 10%.

Bax

My Feedback: (11)

At low throttle settings, engine quitting means that you may need to check the fuel system or the engine's settings. How is it quitting? Rich? Lean? Those will determine how you should go. Remember that at low throttle settings, fuel draw isn't as strong as at higher throttle settings, so the engine may tend to run leaner when you're in nose-up attitudes. Nose-down, the fuel pickup in the tank be actually become unported.

altamash_rah

I am having a simliar issue in my new os 55

here are my specs

Sundowner 50
TX - DX7
RX - AR7000
Servos - 2-JR126MG for tail controls 2-DS821 for aileron and 1 Hitec for the throttle
Engine and Muffler - OS55 with w/ bison pitts muffler
prop: 10x8
fuel and glow plug: Power Master 15% MG and #8 plug

So i averaged about 10-15 minutes each flight for the last 11 flights or so. I am running the highspeed needle about 2.25 turns out from close.

Today i had flown the plane 3 times with 3 succesful takeoffs and landings, all of these flights were at WOT.

On the fourth flight however, i decided to slow down and cruise for a little bit so i dropped the throttle to a about 1/2 throttle and flew around, all of a sudden the engine started to lose rpm and shut down, I dead sticked the plane safely in to some weeds , the only damage from the landing was that one of the pipes from the bison pitts muffle snapped off, but other then that the plane is perfectly fine!.

I am not sure as to what happened, my guess would be that the engine is still new and only has about 4-5 tanks gone through it, with each tank of gas i do two takeoffs and two landings and flying the plane at a lower throttle may have loaded up the engine with too much fuel causing the igniter plug to stop causing combustion. im hoping that this was a minor fluke and that if i continue to do the next few tanks at WOT that the engine will have sufficient break in for me to cruise around at slower speeds



any suggestions or theories as to why this happened will help tremendously, thanks in advance!

kerwin50

On my engine the low speed adjustment was to rich, I ended up screwing the low speed needle in about an 1/8.
I would let the engine run at a fast idle for a couple of minutes then gun it if it hesitated or died I would screw the needle in just a tad.
Then I started letting her just idle for a couple of minutes and do the same thing.
Now she's running great.

altamash_rah

I tryed that, but i let the engine load up at idle for about a few seconds instead of a couple of minutes, ill try it your way,

i guess flying around at mid range for a a minute or two then trying to gun it was caused by a rich LSN,

during the break in i found i needed to turn the LSN 1/8 just so the engine would get up to WOT, i guess it may need another 1/8 turn, this bison pitts muffler sure looks much better then the stock, would hate to have to switch to stock!

thanks for the response!

Bax

My Feedback: (11)

If you are using an after-market muffler, please make sure it provides enough pressure. Some non-OS mufflers don't provide enough pressure to give you good fuel delivery. This can be especially so if the engine's running at a part-throttle setting. That's because the engine is giving you reduced output and lower exhaust pressure.

kerwin50

O now it all comes to light, didn't know you had an aftermarket muffler. Just like Bax says.
I have a slimline muffler on a 46 that did the same thing and I put a large wheel collar in each down tube with a long screw to give me more back pressure.
If that doesn't work and you really want to use that muffler then you might want to consider a perry pump.

franz2

Greetings,
I also have a brand new .61 FX, which is dead sticking at landing. I hesitate go to idle while in flight because I'm afraid that it will do it there, so as of now I experience the dead stick on landing, when I throttle back to idle. It seems to transition from low to high speed very well, and vice versa. Also, will idle for about 30 seconds to a minute before quitting on the ground while not in flight. Did it today.. 70 degrees and dry conditions. Any suggestions would be appreciated.