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Four Stroke carb seal?

Old 09-14-2021, 06:29 AM
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Stuntguy13
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Default Four Stroke carb seal?

Has anyone tried sealing the carb barrel on OS carbs with any type of heavy oil or grease to prevent airleaks from changing fuel setting during flight. What other things can you do to keep a good seal?

Best, DennisT
Old 09-15-2021, 02:23 AM
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1QwkSport2.5r
 
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If your mixture changes in flight, I’d be ensuring the spring behind the barrel is not stuck or squashed. Many carbs have a spring that pushes the carb barrel out slightly holding it against the alignment groove which prevents the barrel from moving in and out against the “slop” in the groove. I would look at a parts diagram to make sure it’s supposed to have a spring and if so, check to ensure it’s still there. If it is, sometimes stretching the spring out a little bit will put more tension on the barrel to solidify it a little bit.
Old 09-19-2021, 05:02 PM
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HansenTsang
 
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Originally Posted by Stuntguy13 View Post
Has anyone tried sealing the carb barrel on OS carbs with any type of heavy oil or grease to prevent airleaks from changing fuel setting during flight. What other things can you do to keep a good seal?

Best, DennisT
How is the O-ring inside the carb? That can get hard and not seal properly. Finding an O-ring that fits inside and against the intake manifold is a chore. I had to try out quite a few different O-ring sizes before getting one that fits. That's on my 120 Surpass II.
Old 09-20-2021, 03:17 PM
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1QwkSport2.5r
 
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I think you need to find some 500,000 weight grease or heavier to “calm the air leak”.

LMAO.
Old 09-21-2021, 01:59 AM
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1200SportsterRider
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And fuel will turn that into the consistency of water.

There's one in the, honest.
Old 09-21-2021, 02:30 AM
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1QwkSport2.5r
 
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I was kidding. In no way would thick grease fix a leak long term. I was poking fun at something said by another fellow.
Old 09-22-2021, 01:48 AM
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jaka54
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Hi!
If your engine does not hold a setting it is more likely something else than leakage in the carb.
A too big tank could also be bad for the engine as it could not tolerate a too wide pressure variation as the fuel level in the tank alters.
It is also vital that the tank is as close to the engine as possible and that the center of the tank is in line with the carb intake orifice as the plane sits horizontal.
Glow plug is also important. OS F is what you should use.
Fuel: 5%-10% nitro, no more is needed!

Last edited by jaka54; 09-22-2021 at 01:53 AM.

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