Mercruiser 120 Fuel Line Problem

mlackore

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Jul 11, 2009
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23
What is the purpose of the packing nut and rubber packing against the lower flare nut fitting on the Mercruiser 120 fuel line? This is the fitting on the fuel pump. The upper fitting that threads into the carburetor is just a solo flare fitting.
 

Bondo

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Re: Mercruiser 120 Fuel Line Problem

Ayuh,... It allows for vibration, not work hardening the metal line, 'n Breaking...

If it were flared, both ends, it would eventually break...
 

mlackore

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Jul 11, 2009
Messages
23
Re: Mercruiser 120 Fuel Line Problem

I think you misunderstood me. Both ends are indeed flared fittings but here is a packing nut that is threaded onto the top side of the fitting on the pump end of the fuel line. This an OEM Mercruiser fuel line. The packing washer had rotted out and I needed to replace the whole fuel line assembly and I got to wondering why that extra packing and packing nut is even there if both ends are a flare fitting.
 

Bondo

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71,310
Re: Mercruiser 120 Fuel Line Problem

I think you misunderstood me. Both ends are indeed flared fittings but here is a packing nut that is threaded onto the top side of the fitting on the pump end of the fuel line. This an OEM Mercruiser fuel line. The packing washer had rotted out and I needed to replace the whole fuel line assembly and I got to wondering why that extra packing and packing nut is even there if both ends are a flare fitting.

Ayuh,... For the reason stated above... To stop metal fatigue...
 
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