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Ronbstewart · 03-27-2017, 06:20 PM

My Monaco has a 7.5 Onan that I have a hard time getting 200 hrs before it shuts down due to fuel filter issue. Change the filter and its good to go. I going to add an inline filter between the fuel tank and Gen filter, Gen filter is NAPA 3063 or Cummins Onan 149-2513. My question I have searched until I'm blue in the face trying to find the Micron value of the filter with no luck. I purchased an inline Wix (33972 2 micron) from O'Reilly which I feel is maybe a bit too fine (haven't installed it yet) I would like to step down 10-15 microns from what generator mounted filter is.

96 Wideglide · 03-27-2017, 07:31 PM

Where you buying your fuel?
The pickup for your gen is at least 1/4 way up the tank. Shouldn't be any bottom of the tank krud up there, and forget about water.... your engine wouldn't be running.
Are you also having trouble with your engine filters getting plugged?

twinboat · 03-27-2017, 08:00 PM

I would put a, small 30 micron, or a large 10 micron, before the generator filter.

Adding a 2 micron will just plug up fast. Your generator is probably a 10 micron.

I would also attemp to run the tank almost empty to get the old fuel filtered by the engine filters. Then fill with fresh fuel.

I bought a boat with bad diesel fuel. It took a trip from NY to FL and back, to clean up the fuel, enough to get 500 hours on a filter. Went thru a bunch of filters but it's all good now.

Twomed · 03-27-2017, 08:11 PM

Part Details

3063 is a 5 micron... probably why it is so troublesome and overstresses the fuel pumps.

barmcd · 03-28-2017, 06:55 AM

Apparently the PO of my coach had the same problem. I have a Parker R12T 30 micron filter installed in front of the generator.

Ronbstewart · 03-28-2017, 10:24 AM

First thanks to all who replied. Coach has 200 gal fuel tank, when I purchased it years back engine had 1 filter and Winn system that had been bypassed, I had several shut downs due to filter issues. I installed a Racor water separator system with 30 micron filter off the tank and 10 micron on the engine and never had a problem since. I usually fuel at Murphy USA (Walmart) Pilot or Flying J. I also refill at 1/2 tank. Now knowing the size of NAPA 3063 I definitely need something higher between tank and Gen filter. Returning from FL last week I allowed level to drop to 1/4 tank filled up at Walmart in Chatt, TN, started Gen later and it shut down after a while only 125 hrs on filter. A simple fix would be a 5/16 inline filter, but I'm told most inline filters are for gas and using then in a diesel system could cause the filter element to break down causing damage/blockage. I do 85-90% of my own repairs and have all the tools, will look for a filter in the 20-30 range to install between tank and Gen filter.