Forum Discussion

clydedoerr's avatar
clydedoerr
Explorer
Jan 14, 2014

onan fuel filter

Can you change the fuel filter in an onan microquiet 4000 generator from the bottom or do you have to remove the solenoid and control module to get to the hose clamp?
  • It can be changed from the bottom. Put a clamp on the incoming fuel line to pinch off the flow; I use small vice-grips. Remove hose from filter, use a deep socket to remove the filter. Use the new filter to select the socket size.
    Use a bit of fuel proof teflon tape (yellow), or pipe dope, coat the threads on the new filter, thread it in and tighten with the wrench/socket. Install the hose, tighten clamp, remove vice-grips.
    Prime the generator (push/hold OFF rocker, pump starts after a few seconds) until the pump quiets down, then start. Check for leaks.

    I didn't use tape the first time I replaced the filter, had a leak...
  • You can do it from outside. But takes 2 people.
    One to hold an open end wrench on the fuel pump nut.
    The other to lay on the ground and remove the filter with a deep socket.
    I did not put anything on the filter threads.

    Should you need to replace the pump. Than you need to remove the solenoid and control box.

    Working on this Gen. requires a few chosen word's while working on it.
  • BruceMc wrote:
    It can be changed from the bottom. Put a clamp on the incoming fuel line to pinch off the flow; I use small vice-grips. Remove hose from filter, use a deep socket to remove the filter. Use the new filter to select the socket size.
    Use a bit of fuel proof teflon tape (yellow), or pipe dope, coat the threads on the new filter, thread it in and tighten with the wrench/socket. Install the hose, tighten clamp, remove vice-grips.
    Prime the generator (push/hold OFF rocker, pump starts after a few seconds) until the pump quiets down, then start. Check for leaks.

    I didn't use tape the first time I replaced the filter, had a leak...

    X2 - This describes exactly how I replaced my filter. Only exception is that I used a piece of 1/4" dowel to plug the fuel hose. Pretty sure the deep socket was a 9/16". After having a leak at the filter/pump connection, I disassembled and used pipe dope on the threads.
  • I followed the directions given by BruceMc and CloudDriver and was able to change my fuel Filter without any fustration, actually enjoyed it. Felt like I knew what I was doing :)
    They pretty much have it down.
    Thanks guys.
  • Would it help for future changes to add a fuel petcock?

    I've been thinking of this anyway because for storing, I can drain the generator dry including the carb bowl without having to empty the gas tank completely.
  • mlts22 wrote:
    Would it help for future changes to add a fuel petcock?

    I've been thinking of this anyway because for storing, I can drain the generator dry including the carb bowl without having to empty the gas tank completely.

    Another option to run the carburetor bowl dry is to disconnect the power wire from the fuel pump. When I replaced the fuel pump a few years ago I left the connector in an easily accessible location just in case. It's the pink connector on the right in the picture below.
  • j-d's avatar
    j-d
    Explorer II
    CD, is it still Code 36 when it runs out of gas with fuel pump disconnected?
  • Code 36 is listed in the Operator's Manual as "Engine Stopped Fault - Engine Stopped without Command by Controller"

    The first corrective action listed for Code 36 is "Check and fill fuel tank". In other words, it might have run out of fuel.

    Despite my suggestion above, I have never actually disconnected the fuel pump wire to run the carburetor empty. I run the generator once a month under load if we aren't traveling and put Sta-Bil in the fuel tank during the winter.
  • We have the Microquite 4000 generator. As I have posted a time or two, I added a switch to turn off the fuel pump and let it run out of gas, I have not seen a fault code from doing this.

    Dusty