After engine turned off gas still going into Carburetor

[Tjburden]

1987 3.0 Mercruiser with stock mercarb: Offseason I replaced water fuel separator filter and fuel filter at the carburetor. Had issues with points old post (great help from forum). I received my timing light and was getting ready to set the timing and idle speed. The engine started and was warmed up, I shut her down to loosen the bolt to the distributor and heard a sound from the carburetor. I removed the flame arrestor and observed gas flowing into carburetor. About 3 minutes before it stopped. Is this a needle and seat issue, a one time issues or something else.
Carburetor rebuilt in 2017 and new fuel pump in 2017. Buy ethanol free gas, fill the tank and treat over the winter

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[Bt Doctur]

leaky needle and seat or excessive fuel pump pressure

 

[Tjburden]

I would think on a manual fuel pump the pressure would be low, what would cause high fuel pressure. Leaking needle and seat means foreign material passed into carb.
What are my options?

 

[alldodge]

Remove the top of the carb to get at the needle valve. Replace it or clean and try again to see if that fixed it

If ya see crud in the bowl, need to do more cleaning from filter to carb

 

[Scott Danforth]

I would think on a manual fuel pump the pressure would be low, what would cause high fuel pressure. Leaking needle and seat means foreign material passed into carb.
What are my options?

clean or replace the needle and seat

 

[Tjburden]

Thanks for quick post. I will look at this today if the weather cooperates.

 

[Tjburden]

Took carb apart small piece of metal at needle. Now the bad news apparently cross threaded when I changed out fuel filter. Is this salvageable.

 

[alldodge]

Maybe, the filter housing does have a gasket. Use a wire brush and try to clean up. Don't know what the thread size is, but a tap would clean it up better.

 

[Tjburden]

I do not have access to tap. After cleanup, I am worried about fuel link if I can salvage. How much torque over the recommend can I apply?

 

[alldodge]

Don't over torque, if it doesn't screw all in, then need to cleaning to the threads. If it does leak you need another carb, use it as trade in on a reman

 

[Scott Danforth]

buy a new carb top casting or a new carb

1987 should be a rochester

 

[Tjburden]

Is this a good site. I got this from a post on this forum. https://flyingfishcarburetors.com/Marine-Boat-Holley-Carburetors.htm

 

[Rick Stephens]

My local NAPA has a box of oversize thread cutting fuel inlet nuts. Check to see if you can find that before trashing the carb.

 

[Tjburden]

Thanks for quick response I will give them a try.

 

[Tjburden]

NAPA did not have any oversized thread cutting nuts; however, he is looking through there carburetors for a top. I have cleaned up the threads. Will wait and see if the come up with top if not will look for oversized nut.
thanks everyone

 

[Tjburden]

Will a top from or one of these carburetor work or just the top. The numbers are 815396 on one and 9565A-6.