Fuel Pump Vent Line Pumping Oil into Flame Arrestor
06-13-2010, 10:14 PM
#1
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Fuel Pump Vent Line Pumping Oil into Flame Arrestor
The fuel pump vent tube that comes from fuel pump up to the breather is pumping oil into my flame arrestor. Kept noticing oil puddling on intake. Thought it was valve covers leaking, then discovered it was coming from that vent tube. It runs down the side of my carb. and onto the intake. (454 bbc) What do you do about this? HELP !!
06-13-2010, 10:25 PM
#2
Does your motor have blowby... Age and hrs? Or a lack of venting..no V/C venting?
__________________
Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
Some people are like Slinkies - Not really good for anything, but they
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Last edited by US1 Fountain; 06-13-2010 at 10:28 PM.
06-14-2010, 01:40 AM
#4
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That is not a fuel pump vent tube. It is a safety feature that indicates that the fuel pump diaphram has ruptured. Chances are it is an oil fuel mix and the pump is starting to leak.
06-14-2010, 06:59 AM
#5
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Exactly right, your diaphram has ruptured. And, if it is running down the outside of the carb, the vent connection on the carb is plugged.
The PO of my boat didn't pay any attention to that tube. He did have the engine serviced, so when I test drove it, the fresh oil in the sea water pump drive wasn't flowing through it. A few run hours later, it was - and it was leaking through the oil seals on the sea water pump shaft. Had to rebuild the sea water pump to stop the oil leak after I replaced the pump. A major PITA.
My advice - replace the pump now, and hope you haven't damaged the sea water pump seals. See the recent fuel pump post for a less expensive source-
http://www.offshoreonly.com/forums/d...fuel-pump.html
The PO of my boat didn't pay any attention to that tube. He did have the engine serviced, so when I test drove it, the fresh oil in the sea water pump drive wasn't flowing through it. A few run hours later, it was - and it was leaking through the oil seals on the sea water pump shaft. Had to rebuild the sea water pump to stop the oil leak after I replaced the pump. A major PITA.
My advice - replace the pump now, and hope you haven't damaged the sea water pump seals. See the recent fuel pump post for a less expensive source-
http://www.offshoreonly.com/forums/d...fuel-pump.html
06-14-2010, 05:05 PM
#6
Isn't that tube located in the top section of the pump above the diaphram for that's open to the block for oiling, and will see internal block pressure if there is any? I'm reading 'oil' is being pumped out the tube, not fuel.
__________________
Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
06-14-2010, 08:27 PM
#7
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Is your pump mounted on the sea water pump? If so, when the pump diaphram leaks, it leaks into the oil in the sea water pump. The vent is to route the resulting oil/gas mix to a safe place rather than your bilge (automotive pumps just leak on the road). It would have a high % of oil at first, but will dilute out quickly. And, it will have a gas smell to it.The only other possibility for the oil coming out the fuel pump vent is a failure of the water seal on the water pump. But then you should see oil/water mix.
If the fuel pump is on the block, it could be high internal block pressure, but given the design of these pumps, I'd still be very careful that it was not leaking oil. A leak on a block mounted fuel pump could take quite a while to make the engine oil smell. But, I would still think the mix coming from the tube would smell of gas.
If the fuel pump is on the block, it could be high internal block pressure, but given the design of these pumps, I'd still be very careful that it was not leaking oil. A leak on a block mounted fuel pump could take quite a while to make the engine oil smell. But, I would still think the mix coming from the tube would smell of gas.
