Author Topic: Casting flaw - how to fix?  (Read 2023 times)

Offline 70GS455

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Casting flaw - how to fix?
« on: November 09, 2023, 02:27:05 PM »
Has anyone seen this before? The secondary fuel well at the top has a weak spot or relief at the top gasket surface. It's the clean portion of the ring. The gasket shows incomplete sealing as well. I fabricated a test setup and verified a slow leak. Even with a new thick gasket it still leaked vacuum. When I used high temp bearing grease as a sealer, the leak was greatly reduced to almost zero. Should I file down the local area, or build it up with epoxy? Or?

Offline Kenth

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Re: Casting flaw - how to fix?
« Reply #1 on: November 10, 2023, 04:37:47 AM »
That little thing won't affect the function noticeably if at all.

JMHO

Offline 70GS455

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Re: Casting flaw - how to fix?
« Reply #2 on: November 10, 2023, 07:54:52 AM »
The emulsion tube orifice is 0.027", it is basically a controlled air leak. The gap appears to be a few thousandths or so. It is above the fuel level so it could suck air. It may be enough to change the secondary fuel calibration. The leak rate is different from the other side so they are different
 

Offline quadrajam

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Re: Casting flaw - how to fix?
« Reply #3 on: November 13, 2023, 04:45:40 PM »
Very good picture detail.
I would use a small smidgen of marinetex epoxy on the carb body, thin film of grease on the gasket
as a release agent, then install the airhorn with just those two screws moderatly tight and let it
cure24 hrs. Remove the gasket and inspect, continue assembly.

QJ

Offline 70GS455

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Re: Casting flaw - how to fix?
« Reply #4 on: December 11, 2023, 05:35:50 PM »
Very good picture detail.
I would use a small smidgen of marinetex epoxy on the carb body, thin film of grease on the gasket
as a release agent, then install the airhorn with just those two screws moderatly tight and let it
cure24 hrs. Remove the gasket and inspect, continue assembly.

QJ
That's essentially what I did. Once cured, I touched it up with a small file. I re tested and now it shows no leaks