1977 Evinrude 15hp.
What are the signs that a fuel pump is going bad? Most likely the diaphragm is torn?
What are the signs that a fuel pump is going bad? Most likely the diaphragm is torn?
Fuel Pump on a 15hp Evinrude - diagnosis
- Thread starter mjk
- Start date
- Status
Yeah, that is exactly what it is.
Long story, I was out with the boat last weekend (3rd time since I bought it). The engine died at least a half dozen times while at various speeds. Kind of a hairy situation, given where I was on Labor Day weekend.
I didn't realize until I was almost back to the dock, that my primer bulb was going soft. If I caught the engine prior to dying, I could press the bulb and keep it going.
The issue is this - I also have an older 6 gallon metal OMC tank (the 'self-venting' type). I believe it is in need of a rebuild, as it has a slow leak around the gas outlet.
I didn't realize that some people will say you need to crack the gas cap 1/4 turn to create venting, until I got home that night.
So - is this a gas tank issue, or a fuel pump issue?
Long story, I was out with the boat last weekend (3rd time since I bought it). The engine died at least a half dozen times while at various speeds. Kind of a hairy situation, given where I was on Labor Day weekend.
I didn't realize until I was almost back to the dock, that my primer bulb was going soft. If I caught the engine prior to dying, I could press the bulb and keep it going.
The issue is this - I also have an older 6 gallon metal OMC tank (the 'self-venting' type). I believe it is in need of a rebuild, as it has a slow leak around the gas outlet.
I didn't realize that some people will say you need to crack the gas cap 1/4 turn to create venting, until I got home that night.
So - is this a gas tank issue, or a fuel pump issue?
Likely fuel pump. You can squeeze the bulb and keep them running, but its a PITA.
Rebuild kit is cheap and easy to do
Rebuild kit is cheap and easy to do
OK, when you say the primer bulb was going soft, what does that mean ... It's either empty and squeezes easily, or it's full and does not. If it's somewhere in between, it sounds like the fuel pump is pulling a vacuum ... And that is not a fuel pump problem. It's a tank venting problem.
The tank is supposed to have a one-way vent that lets air in, but not fuel out. If it's clogged it could be all your problems ...
If you look at the fuel gage area on the tank, you will see the word "Drain" next to one screw. This is the one screw you take out to drain the tank upside down at seasons end. It's just a 8 or 10 - 24 machine screw. Take it out with the tank upright and go for a run. If all works well, you know it was a venting problem and can work on that. If it still tries to die, you have a weak fuel pump, or a clogged pick-up screen ...
To service that, you need to remove the fuel gage area (all four screws, and carefully lift out the gage and the pickup tube. Spray the screen end with brake clean and hit it with compressed air. You should be able to see through the screen. It's fine mesh and soldered on. So treat it with care. But it will clean
Put a little grease on the threads when you put that screw back in. Don't go crazy tightening, just snug is good
If you took all four out, put a little grease on the gaskets and the screw threads for now and re-assemble. Try the motor. If all good, you can get new gaskets this winter and fit the fuel gage/pick-up nicely when not boating
The tank is supposed to have a one-way vent that lets air in, but not fuel out. If it's clogged it could be all your problems ...
If you look at the fuel gage area on the tank, you will see the word "Drain" next to one screw. This is the one screw you take out to drain the tank upside down at seasons end. It's just a 8 or 10 - 24 machine screw. Take it out with the tank upright and go for a run. If all works well, you know it was a venting problem and can work on that. If it still tries to die, you have a weak fuel pump, or a clogged pick-up screen ...
To service that, you need to remove the fuel gage area (all four screws, and carefully lift out the gage and the pickup tube. Spray the screen end with brake clean and hit it with compressed air. You should be able to see through the screen. It's fine mesh and soldered on. So treat it with care. But it will clean
Put a little grease on the threads when you put that screw back in. Don't go crazy tightening, just snug is good
Last edited:
- Status
