I have been mowing with a JD F1145 front mower for several seasons now. It’s powered with a 3-cylinder Yanmar diesel engine (3TN75RJ) and has been a great mower for our hilly property.
One thing that has always been a hassle though is the mechanical lift pump kept having issues. It is fed by two different fuel tanks, with a selector switch in between. This leaves a lot of fuel lines and connections for a vacuum leak. Once the lines get old and tanks get dirty it doesn’t take much for one suction leak to start pulling air into the fuel system. Then the engine cuts out and won’t restart until you bleed the air – usually on the steepest hill and farthest point from the garage!
After replacing all the fuel lines, the fuel filter, dropping and cleaning both tanks I figured the problems were behind me. They were not. It only lasted about 6 months before I started having the same issues again. About to give up, I tried a cheap electric fuel pump from amazon – wow what a difference! I wish I had started with that!
I have 2 seasons on this pump already and it is still going strong. Now whenever I change the fuel filter or need to prime the system for any reason all I have to do is turn on the key switch. No more endlessly pumping that little primer lever on the lift pump.
Here are the items I used:
The electric fuel pump was very easy install. The pump does not draw much power so I just spliced it into the power feeding the engine shut-off solenoid. I believe it was the black and red/black tracer wires. It should have 12v when the key switch is in the run position.
The replacement fuel filter is optional but has a better fuel/water separator and the water drain and is easy to get to / check during regular maintenance.
If your fuel lines are old and dry-rotted it is probably a good idea to replace them at the same time. I used SAE 1/4″ lines rated for fuel / diesel.
The old mechanical pump can be removed and replaced with a block off plate if you have one. I just added a short piece of fuel line to both the in and the out ports in a loop. If the mechanical lift pump diaphragm / membrane ever starts leak oil, it will just be pumped endlessly in a circle!