O.S. 91FX Ringed Adjustment, Not sure Please Help
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O.S. 91FX Ringed Adjustment, Not sure Please Help
I have a O.S. 91 FX Ringed and it's a very smooth, quite engine. I have it in my Extra 260 and I've been flying it with little or no problems all summer long.
Last Sunday I went to a S.T.A.R.S Airshow in Phoenix, NY and I noticed I started to have a engine issue. Every time I landed and came to a stop after landing, I gave it a little throttle to taxi off the runway and the engine would stall on me. It wouldn't do it all the time, I'd say 3 out of 5 times?
What should I do... is it building up with glow fuel in the time I'm in on my final and landing, making it choke up and stall when I give it gas? Or is it too lean and not getting enough fuel?
It gets tiring yelling " Man on the field " some of the time, not to mention a little embarassing.
Thanks,
Pete
Last Sunday I went to a S.T.A.R.S Airshow in Phoenix, NY and I noticed I started to have a engine issue. Every time I landed and came to a stop after landing, I gave it a little throttle to taxi off the runway and the engine would stall on me. It wouldn't do it all the time, I'd say 3 out of 5 times?
What should I do... is it building up with glow fuel in the time I'm in on my final and landing, making it choke up and stall when I give it gas? Or is it too lean and not getting enough fuel?
It gets tiring yelling " Man on the field " some of the time, not to mention a little embarassing.
Thanks,
Pete
#2
RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
Is your engine idling for a long time on approach, then when you throttle it up slowly does your engine cough and sputter a lot(rich low end), or does it fizzle out and not "cough" (lean low end)
Next time turn your 91 on, let it warm up on the stand or restrained, throttle it up a few times, if it performs good then let it idle for about 30 Mississippi's and then try throttling it up and you'll find out real quick that it's too rich on the low end, it will sputter and cough and either die or have poor throttle response
Next time turn your 91 on, let it warm up on the stand or restrained, throttle it up a few times, if it performs good then let it idle for about 30 Mississippi's and then try throttling it up and you'll find out real quick that it's too rich on the low end, it will sputter and cough and either die or have poor throttle response
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
Yes she sputters and coughs, sometimes I can keep it going by jerking the throttle quickly and it clears up. I guess I have the setting very close, I'll lean it just a hair then. Matter in fact I'll do it right now.
Thanks MetallicaJunkie
Thanks MetallicaJunkie
#4
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
Try the pinch test to see if your lowspeed needle is the problem.
With a warm engine, run it wide open a moment or two to clear it out. Then go to idle and let it settle out and run a short while.
Pinch the fuel delivery line close to the carb to shut off the flow.
If it speeds up before dying, the lowspeed needle is too rich.
If it just suddenly quits, the lowspeed needle could be too lean.
Adjust if needed and repeat.
You want just a hint of speed up.
Adjusting the lowspeed takes a very small screwdriver. Until you are familiar with the pinch test, make the adjustments very small. 1/8 of a turn. And remember what the original setting was. OK, actually you have to remember how much you've adjusted and in what direction.
With a warm engine, run it wide open a moment or two to clear it out. Then go to idle and let it settle out and run a short while.
Pinch the fuel delivery line close to the carb to shut off the flow.
If it speeds up before dying, the lowspeed needle is too rich.
If it just suddenly quits, the lowspeed needle could be too lean.
Adjust if needed and repeat.
You want just a hint of speed up.
Adjusting the lowspeed takes a very small screwdriver. Until you are familiar with the pinch test, make the adjustments very small. 1/8 of a turn. And remember what the original setting was. OK, actually you have to remember how much you've adjusted and in what direction.
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
Thanks Da Rock, I just leaned it a hair this morning and I'll run it later this week and try it again, if I'm still off... I'll do the pinch test you mentioned. I know the pinch test works on the high end needle valve, but I never knew it would work on the line to the carb for the low end. I'll remember that, I just learned something new. Thank You!
My Spotter at the Airshow was OK with the " Man on the Field " call twice. But to me it was a little embarrassing. It's funny... my plane ran fine most of the summer until I had a 1,000 people watching it at the event. Gee what luck eh? I guess my plane gets choked up at big events. [sm=lol.gif]
Pete
My Spotter at the Airshow was OK with the " Man on the Field " call twice. But to me it was a little embarrassing. It's funny... my plane ran fine most of the summer until I had a 1,000 people watching it at the event. Gee what luck eh? I guess my plane gets choked up at big events. [sm=lol.gif]
Pete
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
OK guys, I tested it before I went to work. She doesn't quit after 30 Mississippi's, but she takes her sweet time decreasing in RPM's, then she runs rough on idle at the end of the 30 count. When I flip the throttle quickly forward after the 30 count, she'll hesitate slightly but it doesn't quit... but sputters terribly. I do have a air filter on the carb... would that have anything to do with it? When I want a smooth idle I have to trim the throttle higher than I like because when I smooth out the idle the plane will move. What to do?
Pete
Pete
#7
RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
ORIGINAL: da Rock
Try the pinch test to see if your lowspeed needle is the problem.
With a warm engine, run it wide open a moment or two to clear it out. Then go to idle and let it settle out and run a short while.
Pinch the fuel delivery line close to the carb to shut off the flow.
If it speeds up before dying, the lowspeed needle is too rich.
If it just suddenly quits, the lowspeed needle could be too lean.
Adjust if needed and repeat.
You want just a hint of speed up.
Adjusting the lowspeed takes a very small screwdriver. Until you are familiar with the pinch test, make the adjustments very small. 1/8 of a turn. And remember what the original setting was. OK, actually you have to remember how much you've adjusted and in what direction.
Try the pinch test to see if your lowspeed needle is the problem.
With a warm engine, run it wide open a moment or two to clear it out. Then go to idle and let it settle out and run a short while.
Pinch the fuel delivery line close to the carb to shut off the flow.
If it speeds up before dying, the lowspeed needle is too rich.
If it just suddenly quits, the lowspeed needle could be too lean.
Adjust if needed and repeat.
You want just a hint of speed up.
Adjusting the lowspeed takes a very small screwdriver. Until you are familiar with the pinch test, make the adjustments very small. 1/8 of a turn. And remember what the original setting was. OK, actually you have to remember how much you've adjusted and in what direction.
I just learned a new trick Rock
Try Da rocks method, your low end still sounds rich, you may have it so out of whack even turning it in a little wont do the trick, youll know if you went too far, and you can always go back out to where you started
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
This is Mrs. Oberst - thanks for the tips. The Mr's at work, but I relayed the message to him and he's going to try that pinch test when he can this week.
Thanks so much again for the advice.
Thanks so much again for the advice.
#9
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
One thing not mentioned was replace glow plug with new one. From what you said engine has run great for many flights so plug must be the trouble.
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
OK... I was too rich by 1 full turn. It's idling much better now. I have a remote glow on it so I didn't need to drill another hole in my cowl. I do notice when I disconnect the Glow Plug Ignitor the idle decreases. Why is that? Glow plug has been changed before I did the pinch test.
Pete
Pete
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
ORIGINAL: Luftwaffe Oberst
OK... I was too rich by 1 full turn. It's idling much better now. I have a remote glow on it so I didn't need to drill another hole in my cowl. I do notice when I disconnect the Glow Plug Ignitor the idle decreases. Why is that? Glow plug has been changed before I did the pinch test.
Pete
OK... I was too rich by 1 full turn. It's idling much better now. I have a remote glow on it so I didn't need to drill another hole in my cowl. I do notice when I disconnect the Glow Plug Ignitor the idle decreases. Why is that? Glow plug has been changed before I did the pinch test.
Pete
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RE: O.S. 91FX Ringed Adjustment, Not sure Please Help
ORIGINAL: airbusdrvr
Some engines will just drop a bit of rpm when the glow igniter is removed. I replace my glow plugs when I hear a noticeable drop in rpm when the igniter is removed. But I have had a couple of motors that had a good rpm drop even with a new plug.
ORIGINAL: Luftwaffe Oberst
OK... I was too rich by 1 full turn. It's idling much better now. I have a remote glow on it so I didn't need to drill another hole in my cowl. I do notice when I disconnect the Glow Plug Ignitor the idle decreases. Why is that? Glow plug has been changed before I did the pinch test.
Pete
OK... I was too rich by 1 full turn. It's idling much better now. I have a remote glow on it so I didn't need to drill another hole in my cowl. I do notice when I disconnect the Glow Plug Ignitor the idle decreases. Why is that? Glow plug has been changed before I did the pinch test.
Pete
Thanks... I wasn't sure. I guess even 2 Strokes can be a bit tempermental? Been in this Hobby for 7 years, not only am I learning new things, I always run into some thing that just baffles the heck out of me.
Thanks Da Rock, MetallicaJunkie, TedMo and airbusdrvr. You all were right and my O.S. is running sweeter than ever. I guess that the guys at my club had me adjust it a hair rich on the low end just after break-in and didn't tell me. Its the only thing I could think of on why I was almost a whole turn off on the low end. Who knows, but hey it's good now. When I do the pinch test she slowly increases rpm then dies.
Pete