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Old May 23, 2013, 06:17 AM
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Sturbridge, MA
Joined Apr 2010
18 Posts
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Engine Quits on Landing

Hello
My OS33 keeps quitting upon landing, even if its the rare greaser! Its mounted on an aerobeez yakk55m. I tried enlarging the cowl opening to allow for more hot air to exit. Idles at1800rpm and get a I max rpm of 8100rpm with an 18x8 prop. I'm running a 30:1 mixture with VP 94 octane.

The engine seems to run very strong; plug appears just slightly rich, but quits on every landing. Also noticed that lifting off the ground and dropping maybe six inches also induces a drop in rpm and the engine to sometimes quit.

Please help, I'm at a total loss here!!!!

Also, just called OS and they didnt know for sure. Said possible fuel tank plumbing and clunk not moving. I checked all that and I'm landing each time with a half tank. I'm using a dankal design 16oz tank
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Old May 23, 2013, 07:42 AM
WCB
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NC
Joined Aug 2005
1,075 Posts
May be idled down too low.
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Old May 23, 2013, 09:14 AM
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LesUyeda's Avatar
San Diego, California
Joined Dec 2004
3,491 Posts
Where is the carburetor intake. Are you perhaps getting into ground effect, where air is packed under the airplane, and starving the carb???

Les
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Old May 23, 2013, 01:08 PM
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Sturbridge, MA
Joined Apr 2010
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I guess it's possible that the idle is too low and/or the air is "packing" around the carb. It's a rear mounted carb near the firewall
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Old May 23, 2013, 07:50 PM
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Jacksonville Fla.
Joined Mar 2007
2,216 Posts
I had the same issue with a 3MM 50 cc turned out my tuning was off
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Old May 24, 2013, 02:38 PM
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Sturbridge, MA
Joined Apr 2010
18 Posts
Thanks for the help. I'm beginning to think i have it tuned improperly. I think I'm going to reset the factory settings and retune from there
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Old May 25, 2013, 12:01 AM
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Joined Jun 2008
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Quote:
Originally Posted by LesUyeda View Post
Where is the carburetor intake. Are you perhaps getting into ground effect, where air is packed under the airplane, and starving the carb???

Les
Please explain how the air that "is packed under the airplane" is "starving the carb?"

Kurt
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Old May 25, 2013, 09:16 AM
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San Diego, California
Joined Dec 2004
3,491 Posts
If you force enough air into a cavity, it just presurizes, and there is no flow.

Les
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Old May 25, 2013, 10:36 AM
Zor
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Ontario,Canada
Joined Feb 2007
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Where is the "ground effect" ?

Quote:
Originally Posted by LesUyeda View Post
If you force enough air into a cavity, it just presurizes, and there is no flow.

Les
The ground effect is due to the main wings deflecting the air mass downward under the wings.

Does anyone think it is under the engine ?

Is the prop wash causing ground effect ?

Is the engine quitting when going full idle at altitude ? Some fellow never go full idle while flying.

I believe checking the engine mixtures is the better approach to solve this problem.

Zor
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Last edited by Zor; May 25, 2013 at 10:44 AM.
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Old May 28, 2013, 03:54 PM
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USA, OK, Warr Acres
Joined Feb 2004
530 Posts
just a stab

I'm only making a guess here...is it possible that the slight shock from landing is making an "iffy" electrical connection fail momentarily? I guess you could test for that by mildly bouncing the plane on the ground at idle, with restraints in place of course!
Jim
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Old May 28, 2013, 09:30 PM
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winston mo
Joined Oct 2006
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Quote:
Originally Posted by mosquitowings View Post
I'm only making a guess here...is it possible that the slight shock from landing is making an "iffy" electrical connection fail momentarily? I guess you could test for that by mildly bouncing the plane on the ground at idle, with restraints in place of course!
Jim
Plus one on that
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Old May 29, 2013, 11:39 AM
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United States, TX, Weatherford
Joined Dec 2006
1,671 Posts
Check your tank clunk. Sounds like classic fuel starvation. The clunk becomes uncovered by fuel, and the engine quits. Or nose up attitude and engines starts to stall out or quit. Not getting gas is my opinion.
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