Bleed Fuel Lines on Universal M25?

Sep 29, 2018
28
Catalina 30 Annapolis
I disconnected the fuel lines (at secondary filter and fuel return line) on my Universal M25 this past winter and recently hooked them back up. My electric fuel pump is installed before my Racor. Do I need to bleed the fuel lines? If so, do I need to loosen the nut at roughly twelve o'clock on the attached pic and / or just loosen the knob in the other pic until there is a smooth flow with air bubbles? New to all of this. Thanks!
 

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Feb 26, 2004
21,949
Catalina 34 224 Maple Bay, BC, Canada
Bleeding 101 Bleeding M25 Series Engines 101- A Summary of Links for You

Use the knurled knob to bleed the engine. Usually that's all you need. Sometimes you may need to crack the bleed nut on the top of the secondary. Don't mess with anything on the primary filter housing. Read all the links in the above thread. It's easy.

You should also be aware of this:
Fuel Starvation and The Obscure Check Ball Valve
Fuel Starvation and The Obscure Check Ball Valve
and
Fuel Starvation and The Obscure Ball Check Valve


and save yourself some headaches in the future by becoming aware of the info here:

Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too :)

Diesel Engine - c34.org
 
Sep 29, 2018
28
Catalina 30 Annapolis
Stu,

Thanks for all of the information. I will proceed accordingly.

I got my boat last fall and just replaced the original alternator bracket a few weeks ago.
 
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Nov 24, 2014
130
Catalina 310 Staten Island
I disconnected the fuel lines (at secondary filter and fuel return line) on my Universal M25 this past winter and recently hooked them back up. My electric fuel pump is installed before my Racor. Do I need to bleed the fuel lines? If so, do I need to loosen the nut at roughly twelve o'clock on the attached pic and / or just loosen the knob in the other pic until there is a smooth flow with air bubbles? New to all of this. Thanks!
If I have a full tank and let some fuel spill out of the hose before reattached it, I usually don't have to bleed the system. My fuel lift pump is mounted on the engine between the primary and secondary fuel filters on my Catalina 310
 
Nov 24, 2014
130
Catalina 310 Staten Island
Thanks, Mutton.
Glad you found my post helpful. BTW, I have to replace the fuel hose that goes from the primary racor filter to the fuel lift pump, as it is fraying at the pump connector. Hope I have the same good luck. Mutton Dressed as Lamb; It's what's for Dinner
 
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