77 OEM fuel pump (2 Viewers)

[FJROSS]

Question,

I just finished a restoration on my 77 with stock 2f engine. I have fuel leaking from the bottom of the fuel pump. Threaded connections for supply and return seem tight and dry as well as the hose connections. Is there a diaphragm inside that could go bad? If so, would it leak from the two holes located on the bottom of the pump. I currently have the carb off and being rebuilt so I can't run the engine and look while it's running.

Thanks
Dave

 

[charliemeyer007]

Yes the diaphragm can crack and leak out the weep hole. It can also leak into the crankcase and dilute the oil - sniff test the dip stick.

 

[rkymtnflyfisher]

Looks like this on the inside.

You can get this from @Cruiser Cult.

 

[FJROSS]

Yes the diaphragm can crack and leak out the weep hole. It can also leak into the crankcase and dilute the oil - sniff test the dip stick.

Thanks for the fast reply. I will definitely check the oil for fuel contamination. I had Jim C desmog the carb over ten years ago and even replaced the fuel pump and the engine ran fine. During this restoration, I had the engine/carb rebuilt and started it for the first time. It has only ran for 5 minutes or so. I am having an issue with the carb idling. The fuel solenoid was bad and replaced but still has an issue with idle. Just wondering if the fuel pump with a bad diaphragm could cause this, although the level in the window looked to be in the middle. Off for vacation, so it will have to wait till I get back.

 

[FJROSS]

Looks like this on the inside.
View attachment 3990815


You can get this from @Cruiser Cult.
View attachment 3990816

I just ordered a new OEM one from Toyota but will pick up a rebuild kit for the one that's leaking. I don't think there is 500 miles it although it is over ten years old. Thank you for the link.

 

[73FJ40]

I just ordered a new OEM one from Toyota but will pick up a rebuild kit for the one that's leaking. I don't think there is 500 miles it although it is over ten years old. Thank you for the link.

The destructive property of ethanol-laced gasoline.

 

[charliemeyer007]

Ethanol in the fuel can be hard on the old rubber compounds that were not made for it. Drying out for a long time can cause it to get brittle and crack too. My last mechanical fuel pump got a hairline crack and wouldn't work correctly sometimes. Went to an electric pump.

Fill the float bowl by starting the engine. Then shut it off, disconnect the fuel line at the carb and put it in a coffee can; start the engine and watch the fuel flow into the can - it should be steady pulsing, long gaps between surges isn't good. Pump, line or tank has issues.