Fuel pump sight hose

L

longtravel

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Think i might be having a problem with my fuel pump on my 2003 3.0l . I hear a ticking coming from the carb. Thought for sure it was a valve sticking but oddly enough it's air pressure coming from the sight hose. I pull it off the carb and the noise stops. I did notice last year that there was some moisture in the hose down by the pump but not enough for me to be concerned. My question is , should there be air pressure coming from that sight hose?
 
fat fanny

fat fanny

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Re: Fuel pump sight hose

condensation os never good in the fuel system but for now I would replace the hose and or test it for a good seal, After that test for the obvious and see if the same noise and or air leak reaapears!!!!!!!
 
wire2

wire2

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Re: Fuel pump sight hose

There's no physical reason for any air pressure to be in that hose. It connects the carb interior to the tank side of the fuel pump, to divert fuel back to the tank in case the bowl valve sticks and floods it. The carb on a car will spill it onto the intake manifold, risking a fire. If you see fuel in that hose, there's a problem either with the carb or the fuel pump.

Did you feel the air actually blowing out of the hose? Or are you going by that the ticking stopped when you pulled it off?
 
T

TilliamWe

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Re: Fuel pump sight hose

wire2, what you say may be true, but I was always taught that hose from the fuel pump to the carb was there to let you know when your fuel pump has failed internally. I would guess his fuel pump is failing. There should not be air or fuel in that hose, regardless of its exact purpose.
 
jerryjerry05

jerryjerry05

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Re: Fuel pump sight hose

There shoud be NOTHING in that hose.It's there to stop fuel from going into the bildge.It's probably bad.It might last a while but never take a chance when it comes to gas.J
 
Bondo

Bondo

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Re: Fuel pump sight hose

There's no physical reason for any air pressure to be in that hose. It connects the carb interior to the tank side of the fuel pump, to divert fuel back to the tank in case the bowl valve sticks and floods it. The carb on a car will spill it onto the intake manifold, risking a fire. If you see fuel in that hose, there's a problem either with the carb or the fuel pump.
Click to expand...

Huh,..??..??

The sight tube comes from the atmosphere side of the fuel pump diaphram, to the carb...
If the diaphram Ruptures, it sends the gas into the carb, flooding the motor, telling you there's a Problem that needs Fixin'....
It's the fuel pump VENT,+ little more...

To the OP,... You must have Great Hearing,... Although I Don't think there's actually a Problem...
You're hearing the diaphram flexing...
 
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longtravel

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Re: Fuel pump sight hose

There is definetly air moving through that hose. When the motor is running there is a puff of air that goes with the rpm of the motor. When the hose is hooked up to that small 90 degree fitting it makes a ticking sound. It's loud enough to hear with the hatch closed. Right now there is no fuel in the tube at all.
 
wire2

wire2

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Re: Fuel pump sight hose

Bond-o said:
Huh,..??..??

The sight tube comes from the atmosphere side of the fuel pump diaphram, to the carb...
If the diaphram Ruptures, it sends the gas into the carb, flooding the motor, telling you there's a Problem that needs Fixin'....
It's the fuel pump VENT,+ little more...

...
Click to expand...
Ah! You're right Bond o.
It was explained to me many years ago, I had since confused the exact process. I had the purpose right, (prevent raw gas discharged in the engine compartment) but the method wrong. I stand corrected. Thanks.

Now, is it possible that the pump return spring is broken, causing the cam lobe to slap the push rod, making an audible click? It would still pump fuel, just at less GPH.
 
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longtravel

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Messages
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Re: Fuel pump sight hose

Noise goes away when the hose is removed from the fitting on the carb. It's not a noise from the pump. It's noise from air pressure moving through the fitting on the carb. Almost sounds like a rotory sprinkler. TSssss tsssss tsssss noise. My question is should there be any air movement through that sight hose? Hoping someone Can check next Time they run their motor.
 
wire2

wire2

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Re: Fuel pump sight hose

Bond-o said:
Huh,..??..??

The sight tube comes from the atmosphere side of the fuel pump diaphram, to the carb...
If the diaphram Ruptures, it sends the gas into the carb, flooding the motor, telling you there's a Problem that needs Fixin'....
It's the fuel pump VENT,+ little more...

...
Click to expand...
Ah! You're right Bond o.
It was explained to me many years ago, I had since confused the exact process. I had the purpose right, (prevent raw gas discharged in the engine compartment) but the method wrong. I stand corrected. Thanks.

Now, is it possible that the pump return spring is broken, causing the cam lobe to slap the push rod, causing the audible click? It would still pump fuel, just at less GPH.
 
Bondo

Bondo

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Re: Fuel pump sight hose

Ah! You're right Bond o.
Click to expand...

Ayuh,...:D :D

I was Surprised to read what I read in Your post,....
 
M

maccini

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May 29, 2010
Messages
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Re: Fuel pump sight hose

longtravel said:
Think i might be having a problem with my fuel pump on my 2003 3.0l . I hear a ticking coming from the carb. Thought for sure it was a valve sticking but oddly enough it's air pressure coming from the sight hose. I pull it off the carb and the noise stops. I did notice last year that there was some moisture in the hose down by the pump but not enough for me to be concerned. My question is , should there be air pressure coming from that sight hose?
Click to expand...



I have an 03 3.0L and I'm having a problem with my throttle. When I go to take off the boat bogs down and stalls or it bogs down and then takes off. It also revs up then revs down in cycles in mid throttle. Are you having this issue? The reason I ask .... I sprayed in carb cleaner yesterday and when I had the engine cover off I head the ticking you are talking about. It sounds like a valve tap but I wasn't sure what it was and after moving my ear around it sounded like it was coming from the carb but I ran out of time troubleshooting. The boat doesn't get used much, I only have 80 hrs on it. I'm just wondering if you have the same symptoms.
 
L

longtravel

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Joined
May 28, 2009
Messages
8
Re: Fuel pump sight hose

maccini said:
I have an 03 3.0L and I'm having a problem with my throttle. When I go to take off the boat bogs down and stalls or it bogs down and then takes off. It also revs up then revs down in cycles in mid throttle. Are you having this issue? The reason I ask .... I sprayed in carb cleaner yesterday and when I had the engine cover off I head the ticking you are talking about. It sounds like a valve tap but I wasn't sure what it was and after moving my ear around it sounded like it was coming from the carb but I ran out of time troubleshooting. The boat doesn't get used much, I only have 80 hrs on it. I'm just wondering if you have the same symptoms.
Click to expand...

I also have a slight bogging problem off idle. Start it up, let it warm up, idle out of the canal and go to accelerate and it will bog. I just feather the throttle till it goes and then it's fine. I've rebuilt the carb, drained the tank, added a fuel/water seperator and checked the timing. Maybe it is the pump, guess I'll try that next. Let me know if the noise you are hearing is the same thing.
 
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