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Having a similar issue in my coach. But my davco fuel bowl is emptied the next day. Makes me wonder if the vent line is clogged which is keeping the system under vacuum as you experienced, then sucking the fuel backwards from the davco into the tank…..
Where would I locate this vent line and hopefully, check valve?
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Easy way to test would be to remove the fuel filler cap and drive it a short distance or let it idle for a little while. See if that makes the problem disappear or not. Then you can further troubleshoot for the checkvalve and vent.
06 M450LXi 3 slide
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Good advice! remove the cap, stuff a rag in the hole and see what happens.
If you remove the polished stainless vanity panel, you can see the top of the tank. The largest line is the one going to the engine. There will also be lines for the Aquahot and Generator. There will be three return lines.
The check valve is in the line going to the engine, just after it connects to the 90 fitting. The vent line is on the far left side of the tank at about arm’s reach, it 90’s and goes over the tank.
With the engine running, look carefully for bubbles in filter. That would indicate a leak in the seal or the incoming fuel line. Either could also explain what you are seeing.
Richard and Rhonda Entrekin
95 Newell, 390 Ex caretaker
99 Newell, 512 Ex caretaker
07 Prevost Marathon, 1025
Maverick Hybrid Toad
Inverness, FL (when we're home
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Anyone rebuilt the priming pump located on top of the fuel tank. I am wondering if in my case air is leaking into system,as the prime pump does not work
John and Diane Dyer
#717 Tampa show coach of 2005- Detroit 60 14L. Quad slides Front entry
Conifer CO
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(Yesterday, 07:33 AM)[email protected] Wrote: Anyone rebuilt the priming pump located on top of the fuel tank. I am wondering if in my case air is leaking into system,as the prime pump does not work
That could be a good culprit, I know this is an issue on old Cat engines I work on. I have not messsed with the priming pump but you may just bypass it and see if it cures the problem.
I did some work on a 96 that we could not get to prime, i ended up replacing the check valve and the fuel line all the way from the tank to the engine. That did the trick. We could not pull fuel through the check valve, I suspect it was gummed up from sitting.
Jeff LoGiudice
Temple Terrace, Fl
1984 Bluebird Wanderlodge PT40
1998 Newell 2000 #490
1986 MCI/TMC 102A3 (sold)
