High Pressure Fuel Pump Test

[ajv00303]

Was wondering why the Schrader Valve was originally located on the return line and not the output line from the pump???
What is the logic behind this? I would expect the pressure to be lower on the return line............or am I wrong in my assumption?

[Rick H]

I don't have a clue to your question. But the whole circuit should be the same pressure until it dumps.

But if you are having a fuel pressure / volume issue there is a screen on the inlet side of the high pressure pump. See if it clogged it will cause issues. You can reverse flow the pump and it will clean the screen but don't run it dry or long. I used mineral spirits. Fixed my issue.

[Bassmeister]

That would be a vst filter....Part # 354190

[ajv00303]

Too late, I broke the top of the pump off while trying to remove the hose.......
Guess I will be buying a new High Pressure.
I did notice some debris in the bottom of the VST chamber where the pump gets inserted.
Will probably start a new thread when I disassemble the VST.

[Rick H]

This works well!

https://www.amazon.com/BONILORA-Compatible-Johnson-Evinrude-5004428/dp/B09NXGLB2S/ref=sr_1_2_sspa?crid=2ZG9EUJHM3KPS&keywords=043934 7&qid=1653004516&sprefix=0439347%2Caps%2C93&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFGVjFFN DAzSE1MR1YmZW5jcnlwdGVkSWQ9QTA3NDc0MzgxRjY3TVJaTUx PTkVGJmVuY3J5cHRlZEFkSWQ9QTAzMzUyMzgyRkUyRzQ5WFpZM UNLJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGl yZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

[ajv00303]

That's exactly what I just bought.
I am having great difficulty removing the end plates from the VST.
Any suggestions?

[Rick H]

Sorry never been that far. I have avoided ficht's as much as possible but this one was my FIL's

I was having a problem with it miss firing after a 1/4 mile run at full throttle that would go away if you stopped and let it idle a few minutes then drop the hammer and same again. So I knew it was a volume issue but the pressures were low normal. Ordered that pump and when I took the old one off I found the screen issue and cleaned it by reverse flow as I explained earlier. But did confirm that aftermarket pump worked on the water a few hours. Put the OEM back on and keeping the aftermarket for a spare.