Fuel Filter Change Question

Stu Jackson · July 23, 2011, 09:07:35 AM

Quote from: Kevin Henderson on July 23, 2011, 08:57:14 AM
BTW.. What diameter is the fuel line inlet to the Racor?

3/8" supply, 5/16" return and a few very small lines between the injectors (1/4"?)

Ron Hill · July 23, 2011, 12:48:55 PM

Kevin : The fuel line inlet is a barbed fitting for a 3/8" fuel hose. I believe that the fitting that screws into the Racor is a 3/8" NPT tapered thread.

What you can do is make a clamp out of a needle nose pliers and clamp off the fuel line (use a couple of thin wood strips to protect the fuel hose). Then remove the barbed fitting from the Racor, screw in the threaded ball valve fitting into the Racor and then the old fitting gets screwed into the other end of the ball valve. Reconnect the fuel hose, bleed the system and you're good to go!

I like to use non harding Permatex rather than Teflon tape on the threads, but that's your choice.

A few thoughts

Craig Illman · July 24, 2011, 10:59:42 AM

Some Racors use tapered NPT and some use a straight fitting with an O-ring. Sorry, I can't remember which. Mine used the o-ring fittings.

Check out this site: http://fittingsforracor.com/default.asp

Criag

Lance Jones · July 25, 2011, 05:42:09 AM

Interesting fuel filter change. My Racor doesn't have a 1/4 or 3/8ths fitting so the shut off valve project is shelved for a bit. Changed the filter easily enough. I thought I bled the filter enough by turning the knurled knob on top of the filter. Motor started up fine after allowing the pump to run a bit. I ran it for 10 minutes. shut her down. Next morning we went for a sail. Motored out of the slip and shut down -- no worries. Great day long sail. Started motor. Lowered sails. Started back in. Motor died. Hummm. Turned nob on top of filter to bleed. Wouldn't start. Traced fuel line, found the knurled knob on top of the motor (I guess this is the one I should have been bleeding through the whole time...) and opened it 1/4 turn and bled system. Motor started fine.

I'm glad I followed the advice of only change one at a time so you know which system you screwed up. Now I know how to PROPERLY Bleed the system! Glad I read about this on the site or I wouldn't have thought to look further down the fuel delivery process. I may have read it wrong; but, I'll remember it for life!

Kevin Henderson · July 25, 2011, 08:08:58 AM

Lance,

Glad everything turned out fine. I too wondered about bleeding utilizing the valve on top of the filter. One day when Ralph was aboard Pau Hana he distinctly pointed out the bleed valve to be used that is mounted on the engine. Your experience has even more so solidified the fact.

Lance Jones · July 25, 2011, 08:25:27 AM

Now on to the secondary filter!!!! Thanks so much to yous guys (Gender neutral statement...). I couldn't have done it so smoothly without you.

Stu Jackson · July 25, 2011, 01:33:31 PM

Thanks, Lance, glad it worked for you. I added "...or the knob..." on the Racor to the Bleeding 101 topic: http://c34.org/bbs/index.php/topic,6377.0.html

You need do NOTHING at the Racor except taking the filter off and replacing it.

The KNOB, as you say, is ON THE ENGINE, just like Bleeding 101 says.

Good for you.

Ron Hill · July 25, 2011, 05:46:36 PM

Kevin : Let's recheck the fuel line sizes.
The main lines from the tank to the Racor/fuel pump/engine fuel filter/injection pump/ are all 3/8" diameter.
The fuel return is 1/4" diameter.
The lines from the aft most injector to where the fuel return line connects (and between injectors for the M25 only) are 1/8" or 3/16" lines.