We have an Onan 4000 Micro Quite and I wanted to change the fuel filter. After checking it out yesterday I wanted to check with the experts on the forum before I started the project. I have done all the maintenance on the gen set so far but the fuel filter looks a little more complicated. Could someone show me the way.
The fuel filter on the Onan 4KY screws into the suction port on the fuel pump. The easiest way to change the filter is as follows:
1. Locate the fuel hose where it goes into the left side of the generator box, loosen the clamp, pull the hose off the barb and plug the hose (a 1/4" dowel worked for me).
2. The fuel filter looks like this. Using the right size deep socket (I think it was 9/16") unscrew the filter from the pump.
3. Screw the new filter onto the pump, being careful not to cross thread. Don't over tighten.
4. Reconnect the fuel hose to the barb on the filter and tighten the clamp.
Note: The first time I did this I had a slow leak of gas from the connection between the filter and the pump. I removed the filter and added some pipe dope to the threads on the filter, being careful to keep the dope away from the end of the threads where it could come off and get into the pump. No leak since.
One comment. I just did a genny tune up. When I replaced my fuel filter, I had to remove the oval rubber grommet around the hole that the fuel line goes through that connects to the fuel filter. I couldn't get the socket on it until I removed the grommet.
It goes back on very easily, especially if you use a screwdriver to help it in. It just adds a minute or two to the job.
CloudDriver is right on, just unscrew the old one and screw in the new one.
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