Fuel Line Drained the tank

[kytooner]

1994 Mercury Mariner 60hp. Replaced fuel line last year. First time out with new fuel line. Boat ran great all day. Parked it and overnight and was noticing fuel drops in the water. When I went to disconnect fuel line I noticed fuel at the connection point on motor. Then realized the tank was empty about 15 gallons. It's an attwood mercury version fuel line with no spray disconnect at tank. Odd that it ran fine all day and I didn't notice any fuel dripping "I swam next to engine for an hour"

Any ideas as to what would cause this? Are attwoods known problems. Something else I should look at? Anything I can do prevent siphon action in the future?

Thanks in advance.

 

[Chris1956]

For fuel to siphon, the end of the fuel hose needs to be lower than the fuel level in the tank. If the fuel line doesn't leak, and it is connected to the motor, which is higher than the fuel level, it should not siphon.

Have you checked under the motor cowling for leaks?

Is the motor running smooth, or does it hesitate? Fuel pumps have diagrams which can leak raw fuel into the crankcase. They only do this when running, but usually the engine accelerates poorly.

Fuel thieves?

 

[kytooner]

Engine is below the fuel tank. It's a pontoon so not much I can do about that without major addition.

Engine was running great. No hesitation and no sign of leakage during the day.

 

[roscoe]

Well, either disconnect the fuel line when finished using it, or add a fuel shut off valve to the fuel line.

 

[kytooner]

Well, either disconnect the fuel line when finished using it, or add a fuel shut off valve to the fuel line.

Well that would stop leaking when not on board. Still curious as to what would cause this to happen. I've ordered a new quick silver brand fuel hose to see if that fixes the issue.

 

[dingbat]

I've ordered a new quick silver brand fuel hose to see if that fixes the issue.

Attwood fuel lines are a known source of problems.

I would buy some A1 marine fuel hose and an OEM Primer bulb and make your own hose assembly

 

[Chris1956]

Gee, fix the leak in the fuel supply system under the cowling.

 

[kytooner]

Attwood fuel lines are a known source of problems.

I would buy some A1 marine fuel hose and an OEM Primer bulb and make y

Gee, fix the leak in the fuel supply system under the cowling.

well maybe it is a fuel line under the cowling though I would think I would notice that ran on muffs cowling off prior to going to water and the fact that connector was soaked in gas made me think leak at connector but liquid does what liquid does so maybe it somehow leaked off fuel system under cowling and and onto connector. The other thing that made me think connector was evening time not being used where as I would think fuel supply system under cowling more apt to leak during or immediately after use. I'm going down with new fuel hose from tank, and fuel line in case it sprung a leak under cowling. Carb is on the other side of engine so less thinking stuck float but again liquid does what liquid does. Thanks to all for thoughts.

 

[ryan 98]

Was your motor trimmed up somewhat when it was sitting? If a float needle sticks it will just overflow out the throat of a carb and pour out the front by the fuel line. I've had this happen to me before. I also think to some extent these motors were never designed to have constant gravity feed fuel pressure on them. In most boats the tank Is lower. If you trim them all the way up at night you can usualy expect a needle not to seat fully when the carb is on that angle. I had a boat with a bow tank that I tipped right up on the trailer with the motor trimmed up for a rain storm. Didn't even think about the fact the tank was now above the motor and came out to a big rainbow on the ground the next day

 

[Texasmark]

Well that would stop leaking when not on board. Still curious as to what would cause this to happen. I've ordered a new quick silver brand fuel hose to see if that fixes the issue.

If you had a hole in the fuel line between the fuel pump in the engine and the tank, your engine wouldn't run or would labor because the fuel pump sucks whatever is in the line...if the line has a hole in it or a mis fitting connector, or a clamp loose enough to let air in the pump won't/shouldn't be able to satisfy the engines needs and it would labor.

However, If the engine were tilted up there would be a possibility that a malfunctioning float controlled needle valve in the carburetor(s) could be your leaking problem. I'd do as Roscoe said and put a shut off valve in the line, or if there is a connector at the engine, disconnect the fuel line at the engine.

 

[kytooner]

If you had a hole in the fuel line between the fuel pump in the engine and the tank, your engine wouldn't run or would labor because the fuel pump sucks whatever is in the line...if the line has a hole in it or a mis fitting connector, or a clamp loose enough to let air in the pump won't/shouldn't be able to satisfy the engines needs and it would labor.

However, If the engine were tilted up there would be a possibility that a malfunctioning float controlled needle valve in the carburetor(s) could be your leaking problem. I'd do as Roscoe said and put a shut off valve in the line, or if there is a connector at the engine, disconnect the fuel line at the engine.

Trim is broke so not trimmed up other than where it sits for all time use which is justly slightly trimmed above straight down. fuel hose is new so not likely a hole and as stated it would not likely work well. Yes connector at the engine which is where the gas seemed to be coming out. But the stuck float is a good think to consider.

 

[kytooner]

Installed new Merc Quicksilver hose no sign of leakage.

 

[kytooner]

Installed new Merc Quicksilver hose no sign of leakage.

2 weeks later still no leakage. I guess lesson learned to get oem parts.