Fuel pump/lift pump failure

[LeslieTroyer]

Your over thinking it, but I have 1/4” quick on positive and ring on ground. I’d probably go with weather pak next time.

 

[Witzend]

Anything better than a shovel connector.

 

[JK_Boston_Catalina310]

Anything better than a shovel connector.

I use the anchor marine ones that have a plastic lip to help prevent accidentally contact.

Jesse

 

[Muttondressedaslamb]

Check for corrosion on the shovel connector that feeds the current to the fuel pump. It is the wire right on top of the pump.
An indication of high resistant to the power feeding the pump (possible caused by corroded connections) is that your buzzer will not sound if you turn your key in the on position (not the spring loaded position). This a little known diagnostic feature letting you know there is a problem. The ground for the buzzer circuit is through the induction coil of the fuel pump. The fuel pump will not run until you have oil pressure, or if you turn the key to the spring loaded position. Once the engine has oil pressure then +12v will be applied to the pump through the oil pressure sensor. This also has the effect of turning off the buzzer as now it has no ground.
Hope this helps.

Could not help chiming in. I own a 2003 Catalina 310 with the original fuel pump. Unfortunately, the fuel pump is wired to the same alarm as the oil pressure switch, so when the buzzer and light go off, it is hard to tell which is the culprit. Starting at the end of last season, it was happening intermittently, and has been almost constant since I launched the boat. I tried fiddling with the wires on the fuel lift pump, and the light and buzzer went out for a while; all but ruling out low oil pressure or defective switch. I am just going to replace it to be on the safe side, and if the problem continues, call in a mechanic

 

[Muttondressedaslamb]

Anything better than a shovel connector.

I don't "dig" them them either, so lets just call a spade a spade

 

[LeslieTroyer]

Could not help chiming in. I own a 2003 Catalina 310 with the original fuel pump. Unfortunately, the fuel pump is wired to the same alarm as the oil pressure switch, so when the buzzer and light go off, it is hard to tell which is the culprit. Starting at the end of last season, it was happening intermittently, and has been almost constant since I launched the boat. I tried fiddling with the wires on the fuel lift pump, and the light and buzzer went out for a while; all but ruling out low oil pressure or defective switch. I am just going to replace it to be on the safe side, and if the problem continues, call in a mechanic

the purpose of tying the lift pump into the low oil switch was to starve the engine of fuel in low oil pressure situations. depending on fuel tank position and fill level this may not work. The pump comes on when you have OP or when glow plugs are on (gives engine fuel to start).

The “old” way these engine are wired turns on the pump with the key switch. I monitor the OP and don’t need a nanny that only works some times so this is the way I run.

 

[Muttondressedaslamb]

Do you have an oil pressure gauge

the purpose of tying the lift pump into the low oil switch was to starve the engine of fuel in low oil pressure situations. depending on fuel tank position and fill level this may not work. The pump comes on when you have OP or when glow plugs are on (gives engine fuel to start).

The “old” way these engine are wired turns on the pump with the key switch. I monitor the OP and don’t need a nanny that only works some times so this is the way I run.

 

[LeslieTroyer]

Do you have an oil pressure gauge

Yes. I installed it on the OP manifold - which is not on later engines like yours. I also have a oil temp gauge installed on my remote oil filter mount.

 

[marchem]

Yes. I installed it on the OP manifold - which is not on later engines like yours. I also have a oil temp gauge installed on my remote oil filter mount.

Les, there is an oil pressure manifold on the M25XPB. I installed a pressure sensor on mine and the corresponding gauge in the engine control panel in the cockpit. I thought I had a picture of it, but can only find this page from the parts manual. #15 and 16 are 1/8" NPT fittings. Not easy to get to, but real nice to be able to see the actual pressure.

 

[marchem]

Here’s a picture of the two oil sensors. The big one is pressure, and the small one is the normal switch.