2001 Mercury 50 hp 4 stroke fuel leaking from overflow tube

[Fiddlegeek503]

Hi everyone. My engine has a lot of fuel coming out of the carburetors’ overflow tube that has started somewhat recently. It starts and runs well otherwise. I’ve cleaned and inspected the carburetors multiple times. I’ve checked float levels and needles. I tested the fuel auto enricher. Aside from one questionable bowl gasket, I really haven’t found anything that would cause this. I may disconnect the main tube so I can isolate and see which carb is overflowing. Does anyone have any ideas what is causing this?
2001 Model # 1F51412YD 50 HP ELPT 4

Additional info/timeline/observations
Purchased used 2023
It idled great but would cut out while throttling up.
After cleaning the carburetors/new plugs, there was some mild hesitation while throttling up that improved greatly over time (I figured it may have just needed to be run a bit) but it has not completely disappeared.

Summer 2024 I was operating in shallow water and had the engine trimmed up and noticed fuel leaking into the transom area. Removing the cowling there was fuel leaking from the overflow tube.
I disassembled and inspected the carburetors a second time and didn’t notice anything amiss.
Now while running the motor, it doesn’t matter if it is trimmed up, the fuel streams from the overflow tube and it is even more than before.
Boating season will be here soon - my kids are anxious about not being able to go out on the boat! Many thanks!

 

[cyclops222]

It should be a float problem. Even crud building up in the float needle tip.
Some floats become leaky and start to sink.

 

[Fiddlegeek503]

It should be a float problem. Even crud building up in the float needle tip.
Some floats become leaky and start to sink.

The needles appear to have a hard rubber tip. They are in excellent condition and are clean. I closely inspected the floats for cracks or open seams. None of them had any fuel inside of them.

 

[Fiddlegeek503]

The needles appear to have a hard rubber tip. They are in excellent condition and are clean. I closely inspected the floats for cracks or open seams. None of them had any fuel inside of them.

It should be a float problem. Even crud building up in the float needle tip.
Some floats become leaky and start to sink.

I posted a video of fuel leaking.

The carbs stop leaking after the engine has warmed up but the top port that seems to come from enricher continues to leak. I don’t know what to check next. Any clues? Someone suggested the fuel pump. Clearly it’s pumping fuel though or do I not understand how fuel pump works? Some of these parts aren’t cheap ($200 enricher or $200 for new floats and valves) ) so I don’t want to be taking pot shots at what might be the problem.

 

[Chris1956]

Your top carb looks to be leaking. Likely float or inlet needle and seat. The OEM part number for a carb kit is 8542561. Take a look at ebasicpower or Sierra for a cheaper replacement. I would rebuild the top carb and see if that fixes it.

 

[Chris1956]

Here is amazon carb kit for $16

https://www.amazon.com/8542561-Carburetor-Mercruiser-Quicksilver-Outboard/dp/B0C6MSM178