FUEL PUMP

[EMELLO]

I have a 1971 Glastron with AQ170 Volvo Penta 270 outdrive that has sat for the last 21 years and I have been replacing all fuel lines, cleaned carburetors. The original fuel pump diaphragm leaks so have not been able to locate or rebuild parts for this one. What concerns me about this pump is that it does not have any safety system built into it in case of diaphragm leak and the gas would just drop into the bilge. While searching for a pump and other parts that I need I became aware that a big safety issue had been there with me since I purchased it new. I did get it to run with a temporary pump to check it out, engine has 1500 hrs. on it. Anyone have an idea how to correct this safety issue?

Enos

 

[kenny nunez]

You can add a Carter marine electric fuel pump along with the oil pressure safety switch. Be sure to wire it so that the pump will also operate while the engine is in cranking mode. The oil pressure switch has 3 spade connections, one of them is the pump starter by pass.
The pump will only operate while there is oil pressure.

 

[Donald0039]

I have a 1971 Glastron with AQ170 Volvo Penta 270 outdrive that has sat for the last 21 years and I have been replacing all fuel lines, cleaned carburetors. The original fuel pump diaphragm leaks so have not been able to locate or rebuild parts for this one. What concerns me about this pump is that it does not have any safety system built into it in case of diaphragm leak and the gas would just drop into the bilge. While searching for a pump and other parts that I need I became aware that a big safety issue had been there with me since I purchased it new. I did get it to run with a temporary pump to check it out, engine has 1500 hrs. on it. Anyone have an idea how to correct this safety issue?

Enos

I think if the diaphragm breaks the gas goes into the oil pan and with no gas pressure the engine stops once the carb bown empties.

 

[Donald0039]

You can add a Carter marine electric fuel pump along with the oil pressure safety switch. Be sure to wire it so that the pump will also operate while the engine is in cranking mode. The oil pressure switch has 3 spade connections, one of them is the pump starter by pass.
The pump will only operate while there is oil pressure.

You may need a control with a timed relay, maybe a diode to prevent voltage going from the + lead on the pump to the starter solenoid (assuming you are pulling power from the starter solenoid to run the pump doing cranking) when power is coming from the oil pressure switch to the + lead on the pump.

I looked into this but could not find an marine grade control to power the pump for 10 seconds after ignition is on or after the engine is running.

 

[EMELLO]

I think if the diaphragm breaks the gas goes into the oil pan and with no gas pressure the engine stops once the carb bown empties.

That sounds logical. I didn't think of that, Thanks for the quick reply.

 

[EMELLO]

You may need a control with a timed relay, maybe a diode to prevent voltage going from the + lead on the pump to the starter solenoid (assuming you are pulling power from the starter solenoid to run the pump doing cranking) when power is coming from the oil pressure switch to the + lead on the pump.

I looked into this but could not find an marine grade control to power the pump for 10 seconds after ignition is on or after the engine is running.

I thought about using an electric fuel pump but had already installed a new pump before realizing where the fuel would go if the diaphragm failed, I may still change it over later. Now the water pump needs to be rebuilt, leaking. Have any idea how to remove the bushings? Thanks.

 

[Scott Danforth]

the original mechanical fuel pump lasted 52 years. an electric pump will last 5-7 years. I would bolt on another mechanical pump and it would outlast the boat

 

[Grub54891]

I think if the diaphragm breaks the gas goes into the oil pan and with no gas pressure the engine stops once the carb bown empties.

Nope. The fuel goes to the bilge if the diaphragm leaks. You want a marine pump with the safety hose that runs to the carb. I'm sure some of the leak will get in the oil but not all of it.

 

[alldodge]

I think if the diaphragm breaks the gas goes into the oil pan and with no gas pressure the engine stops once the carb bown empties.

Correct
https://www.ebay.com/itm/115175190307

 

[Grub54891]

Correct
https://www.ebay.com/itm/115175190307

Well, learn something new every day. Never saw that one myself.

 

[Donald0039]

Nope. The fuel goes to the bilge if the diaphragm leaks. You want a marine pump with the safety hose that runs to the carb. I'm sure some of the leak will get in the oil but not all of it.

I believe the hose from the carb to the fuel pump is in case the needle valve on the carb gets stuck and fuel continues to flow into the carb bowl. It drains into the fuel pump.

I do agree with a marine fuel pump.

There are no paths to outside of the engine or bilge in a mechanical fuel pump. You have a metal housing with an inlet and outlet gas line fittings and on the inside of the metal housing a diaphragm and a one way valve (probably) and a lever on a hinge pin that the engine rotating pushes up and down which in turn pushes the diaphragm in and then relaxes it, then in and relax. Pushing of the diaphragm pumps the fuel.

Diaphragm breaks there is no path for raw gas to go except past the lever into the engine and into the oil pan. You loose fuel pressure to the carb, engine runs until fuel bowl is empty and engine stops. Anti-siphon valve in gas tank prevents much gas from getting into the oil pan beyond some while the engine is running on what is left in carb fuel bowl.