Bleeding Fuel System 3GM30F

Ted · Jan 12, 2019

This is not exactly related to your fuel tank project but if you don't already have a vacuum gauge, now would be a good time to add one. The type with a resettable drag needle are the most useful because you don't have to look at the gauge while you are motoring. Just check it at the end of the day to see what the maximum reading was.

kloudie1 · Jan 12, 2019

Hey, Shannon.. was wondering how things were going..
#3 yes, little metal gauze strainer at the tip of the fuel pick-up tube.
Strainer air bleed is on top of the secondary filter next to the fuel pump.. access through inspection port.. The bleed screw itself is the one on top, closest to the engine block.. Caution on aluminum threads that are easy to strip when tightening.. I have always used the easiest one to access, the one that you can see in the picture and have not had problems..
Important to note that the fuel pump is cam driven so the engine needs to be rotated until you get a full stroke on the fuel pump manual lever.. pull the fuel stop in the cockpit.. open the bleed screw and provide a way to catch diesel drooling then as you push the lever, you can feel where it actually starts to move fuel... roll the crankshaft (compression released) by hand a half turn or so (moves cam 1/4 turn) until you get a nearly full stroke from the little lever on the fuel pump.. pump the lever until no air (only diesel) comes out of the bleed screw.. Tighten the screw, if you can tighten while slowly keeping a little fuel drool, that'd be great.. Next open the bleed screw on the HP Injection pump.. on older engines, there is a bleed screw in the middle of the banjo fuel inlet fitting.. If yours does not have that screw, slack the banjo bolt itself to get the diesel to come out when you pump the manual lever.. pump until no air then retighten.. Push the fuel stop back in.. Re-compress and see if it will start.. don't crank for more than 15-20 seconds.. If you are lucky and it starts, let it run a minute then bleed the injectors by loosening the fuel inlet fitting where the pipe enters. Loosen one at a time, let the fuel spray a little, then tighten.. the engine will continue to run on two cylinders as you do each one.. if it doesn't start quickly, close the seacock and remove the raw water hose to avoid water locking the engine if the bleeding goes slowly.. Have someone at the starter or use a remote start button (arrange a signal to stop!); loosen one of the injector inlet fittings and with the compression released, spin the engine and make sure diesel spirts out of the fitting with no air.. Do each in turn then re-connect the raw water hose and open the seacock.. Re-compress and start.. once running, open each inlet in turn and bleed until absolutely no air.. Be careful to close any fitting while still under pressure to avoid air being sucked back into the line.. LONG and sounds complex, but when ya do it, not so bad.. Good luck..
Vacuum gauge would be mounted between the primary filter and the fuel pump.

Ted · Jan 12, 2019

mnmpizza said:
I'm assuming [when installed in the correct place] the vacuum gauge will show my how much 'blockage' I may be experiencing between the engine and tank?

The vacuum gauge will show you the condition of your fuel filter. Make a note of what the reading is when you initially install a new filter and watch the vacuum increase over time as the filter traps more and more contaminants. Some vacuum gauges also have a "reminder" needle which you can manually set at a specific point to remind you to change your filter when the drag needle approaches that point.

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Sailboat.Sequoyah · Jan 14, 2019

This bleeding method works pretty well for me:

1) make sure the primary filter is clean, loosen its bleed screw (mine is a Racor 120, the screw on which like that of the Racor 110 with its metal bowl and cylindrical paper element is a hex fitting on the side of the cast metal body above the bowl), and let fuel run from it by gravity siphon from the tank until all bubbling ceases and then at least a cup of clear diesel with no visible air or dirt in it has run out;
2) bleed the secondary filter, again having made sure it's clean, a smaller one with a metal bowl on the starboard side of the motor next to the small lift pump, which requires you to apply pressure from the little lever on the pump (a pain in the neck, since it wants about 2,036 pumping motions before you get fuel out) or by another means, in my case from a rubber squeeze bulb I installed near the primary filter (easier and quicker);
3) take loose the return hose from the injector pump (you'll find it a little forward and above the secondary filter) and apply pressure until clean, air-free fuel squirts from the nipple, once more putting it out until at least a cup of it has come through;
4) relieve pressure from the cylinders by throwing the little compression levers on top of the motor (there is one for each of your three cylinders, and pulling them forward lets compression out so the motor won't fire), then crank the motor for ten seconds or so to force fuel and any air past them into the return line and back to the tank. Put the levers back to the operating position, and if the motor won't fire do that last step again.

There is more than one way to bleed the system. This is the easiest I've found so far. Someone else may have a better one.

kloudie1 · Jan 14, 2019

Another note, Shannon, when you have rolled the engine to a full stroke on the pump lever, mark the front crank pulley so you can return to that spot easily next time.. Ya may have to roll the crank +/- one turn at the mark because of the cam turning at half crank speed.
The bowl is probably stuck to the gasket and housing.. may require some gentle prying and tapping with a soft face to get it to loosen after the retainer ring is removed. The bowl looks to be in need of replacement..?..

John T1594 · Jan 14, 2019

In 15+ years of working on my 3GM30F Yanmar, including replacing filters and fuel lines, I never had to do a full bleeding that involved the injectors. My circa 2000 engine had a bleed screw on top of the HP injection pump that was a little tricky to get to but it was bled the same way as the secondary filter - just loosen the screw, pump the pump until you no longer get any bubbles and crank the engine. My favorite way of keeping all that dripping diesel under control was to use a couple of disposable baby diaper under the filters and pumps.

JimInPB · Jan 14, 2019

mnmpizza said:
I’m having trouble removing the bowl on my Racor500 ...

Yea, some of those clear view filters are notorious for being hard to remove if they were screwed on tight. I've run into some that were so tight, right out of the box, that I couldn't get them apart & then had the sales guy try to get it apart, only to damage it in the process.

The deal is this -
Those things are rated for a lot of vacuum. In order to be leakproof all the way down to the specified amount of vacuum, they sometimes need to be pretty tight. After fuel has sat in them for a while, the O-ring will often swell & make the fit even tighter. After that, getting them apart just about requires an act of Congress & the effort of 3 men, 2 boys & a mule. This is assuming that you have the type with the threads on the bowl.

I have had my best luck getting those apart by wrapping the filter with a piece of rubber gasket material, then putting a strap wrench over that. On rare occasion, I have had to use more brutal methods. On a good day, I have gotten away with just using a pair of rubber palmed gloves. The cheap orange ones from Home Depot seem to work OK.

I make a habit of carrying a spare filter, bowl, & o-ring set, on any boat I have that uses a Racor. Trying to get a swelled O-ring back in place can be a non-starter. The diameter of the o-ring often grows by a half inch when it gets swelled from fuel exposure.

Edit:
oops, the 500 disassembles differently than the other model of Racor that I was thinking of. Scratch what I wrote above. Sorry about that.

http://www.parker.com/Literature/Racor/Tech_Install/15332_500FG_Turbine_Series.pdf

heritage · Jan 14, 2019

If you are ever stuck out with a failing diesel and suspect that the mesh filter in the bottom of the fuel tank is clogged, try this: disconnect the fuel tank line at the primary filter and blow into it. The air will force the debris off the mesh filter and away from the pickup tube... for a while. Hopefully long enough to get you home and do a little fixing on the tank. I'm assuming that your tank is below the level of the fuel filter.

JimInPB · Jan 14, 2019

mnmpizza said:
Jim, thanks for sharing your knowledge. Was hoping the video would show the removal of the bowl

The last page of the PDF shows how the parts go together.

Maine Sail · Jan 15, 2019

mnmpizza said:
I’m having trouble removing the bowl on my Racor500 to clean up the stains on the inside.

Rebuilding a Racor Turbine Filter (LINK)

Bleeding Fuel System 3GM30F

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