What dimwit thought of that?
 

Helping a friend with fuel system issues, we suspect there may be a leak in the fuel tank pickup tube or at least we would like to eliminate the possibility and while there, remove the filtering screen at the bottom of the tube if it exists.

Well, have a look at what we are dealing with. The pickup tube is completely unserviceable since it's welded into the tank. In literally hundreds of tanks observed I have never seen such a . . . . I can't find the words.

That looks like a frame from a bad sci-fi movie!
"The Return Of The Evil Molten Zardoz"

But at least its a good-looking weld. ;)

Well the boat will never suffer from having the pickup tube stolen, so there is that :rolleyes:

Fude for thought
 

Neil, per Ed that is a nice beefy weld. You could just saw the fitting off and then drill out the old tube. Then perhaps there will be enough material to re-tap larger and install a new tube. :)

Dave Neptune :cool:

Has anyone noticed that beautiful sealant job on the gauge probe to the left of the "mega-weld" fuel tube?

Tom-
That is where I got the inspiration for my Sci-Fi pic!
Wonder if that's "Magic Flex Seal"?

Before going that deep we'll need more convincing the tube is actually a problem. The exercise was to confirm that it wasn't.

I would be tempted to haul the entire tank out and see what else the previous owner's maintenance club had got up to :eek:

...and then not bother putting it back in the boat!!

http://www.moellermarine.com/product...nt-fuel-tanks/

+1.

Bill

Well fellers, the owner is not interested in removing the tank without evidence it is necessary which we do not yet have. We are renewing and modifying the entire fuel system because of air entering the system (diesel). We are eliminating the mechanical fuel pump in favor of a Facet (rebuild and diaphragm maintenance/concerns), eliminating the on-engine fuel filter (a known Yanmar problem), new Racor filter, new fuel hoses throughout and adding my polishing system. His tank is currently at about 3/4 so if after our other fuel system work is done we are still getting air, we will fill the tank and test again. If the air problem disappears we will get after the pickup tube no matter what it takes.

Sounds like a solid plan to me! :D

I was invited back channel to elaborate on the known problems with the on-engine filter for the benefit of our Yanmar friends who may come across this thread either now or in the future.

There are two issues the boat owner's research uncovered:

• Bleed screw on the filter housing - over-tightening the bleed screw tends to crack the housing. How much is too much? When you figure it out it's too late.
• Vibration failure - the ring that holds the filter bowl is known to rattle loose from engine vibration.

I'm far from expert but if one has to tighten the bleed screw hard enough so it doesn't leak AND that it cracks the housing.. sounds like there is no copper washer or it really needs replacing? :eek: ... but then this is apparently happens enough times to be able to be researched..

I don't know either but casting quality/strength would be a factor too. Eliminating it entirely solves any possibility of a problem.

This owner recently had another bleed screw break. The screw is small, threads into a banjo and has a tiny hole drilled transversely for a fuel path. It broke off right at the tiny hole.

I should say he has been chasing a small air leak for a while and his frustration level is at max. I was all for testing to find the problem and solve it directly but a week ago changed strategy. I suggested it might be time for the full Monty, make the entire fuel system as good as it can be, make it his own. One of the potential issues has been he pulls a hose off of a barb to purge air from a changed filter with the mechanical pump's hand bail or an auxiliary hand pump which damages the ID of the hose every time. It's on the suction side of the engine lift pump so a leak would be difficult to find. With a plumbed in polishing system purging is done with a turn of a valve and a flip of a switch. No hose removal, no hose damage and less diesel stank.

I do have a Yanmar and have thought why nylon/plastic:o for sealing in oil. the surfaces are so slick over-tightening would be easy and an issue. Also you have the heat over time making the plastic very brittle. How many times have you broken a plastic cap closing a tube of grease or silicone?:confused:

Fortunately I have a bit of experience with hydraulics and associated stuff. On my 4JH4E (56hp) the filter is a spin on so no biggie. I don't like the plastic priming pump though.

Always remember to treat plastic parts with extreme care. Plastic parts ALWAYS undo with far more stress than they are tightened. This is due to the softness of the plastic and heat combine to allow the soft plastic to "form" on each other for an increase of torque required in breaking it loose~~be careful.

Neil, I may look into your polishing system when I go to 2 Racors for switching the feed and adding another tank for cruising

Dave Neptune :cool:

You can test the existing pickup tube for a leak with a pressure test. You'll need a bicycle pump and a U-tube manometer.
Without leak, you can pressurize the tube (measured in inches of fuel) to the depth of fuel above the bottom of the tube. As you add fuel to the tank, you'll find that the pressure will increase as the fuel gets deeper.
With a leak, the pressure will bleed off to nothing until the fuel level gets up to the leak. As fuel level goes above the leak, pressure will indicate the depth of the leak below the fuel level.

OK, the fuel system modifications are complete. They include:

• A higher volume, more robust primary fuel filter sourced from eBay coupled with a new vacuum gauge also sourced from eBay. This combination was a problem in the early stages so I vacuum tested the assembly on the bench. I found the new quick release T handle that came with the new gauge would bottom out before the filter top could achieve a seal (it secures the top). Reverting to an older gauge mount solved the problem. The final successful test held 5" Hg for 2 days.
  
  Attachment 14674Attachment 14675Attachment 14676
• Disconnecting the manual fuel lift pump in favor of an electric Facet pump. The old manual pump remains mounted to cover the hole on the side of the engine block. The Facet is powered from the keyswitch through an override switch.
• Removal of the Yanmar engine mounted fuel filter. Known issues as discussed earlier.
• Installing a new hose barb style banjo into the injector pump inlet. Previously a metal fuel line from the Yanmar fuel filter attached there.
• Addition of a fuel polishing system with a diverter valve and an override pump operation switch. The diverter valve is plumbed between the Facet pump and the injector pump inlet. It directs fuel from the Facet pump to either the injector pump or the diesel return line. The override switch is a SPDT. Turning on the pump override (for filter purging and fuel system bleeding) isolates the auxiliary pump power from the keyswitch circuit avoiding a backfeed.
• New hoses throughout.
  
  Attachment 14677Attachment 14679

The owner is overjoyed with the ease of dry filter purging and fuel system bleeding with the polishing system. It is much easier and faster.

He took the boat for a 4 hour test run yesterday. The RPM blips, precursors to eventual previous shutdowns have disappeared and to our surprise he can achieve an extra 150 RPM at wide open throttle. This also eliminates our concerns about the pickup tube. Returning to the slip he called with a report and we agreed he should do a quick bleed test at the injector pump just to compare. Previously he would limp home, do the bleed and get frothy fuel every time. This time = solid fuel, clearly improved from before.

A final word about the tank
The slobber of Permatex looks like Hell but it solved a problem a while back although perhaps not elegantly. There is a direct reading fuel level gauge mounted there and that area of the top of the tank was very wavy, so bad that the normal cork gasket had no chance of sealing the installation. Like I said, it might look like shi-shi but it doesn't leak.

Here is the owner's version
 

. . . in reply to a guy having Yanmar 1GM fuel problems on SBO:

I just completely redid the fuel system on my 1GM and will be putting together a blog post (with pictures) on the Ericson (EYO) site once I get a chance. Following the design of my friend Neil Dutton and based on some suggestions from Guy Stevens (on the EYO list) this is what I did:

I disconnected the on-engine mechanical lift pump and removed the small on-engine fuel filter altogether, including the metal lines that ran to the lift pump and to the injection pump. The lift pump is still attached to the engine but both lines are unhooked so the pump does nothing. (No need to cap off the in/out ports of the lift pump; just disconnect both lines.) The function of the mechanical lift pump is now handled by a Facet electric pump. I put a banjo barb fitting on the injection pump so that I could plumb directly to it from my large Racor 500 filter. I also installed a diverter valve so that I send the fuel either to the injection pump or into the fuel return line for priming the large Racor and/or polishing the fuel in the tank if I wanted to. I also have a SPDT switch that allows me to energize the pump from inside the engine compartment without the ignition switch on. I used new 1/4" ID fuel hose and hose clamps throughout.

So here is the direction of the flow, starting at the tank:
(1) Tank
(2) Input side of the Racor 500
(3) Output of Racor 500 to input of the Facet electric pump
(4) Output of the Facet electric pump to the center input of the diverter valve.
(5) One side of the diverter valve output goes directly to the injection pump
(6) Other side of the diverter valve output is teed into the fuel return line.

This works fabulously.

To prime the empty Racor, I set the diverter valve to output fuel into the fuel return line. I throw the switch and listen to the sound of the pump, which changes noticeably when the Racor fills with fuel. Run for a short time beyond that (just for good measure) and the filter is primed. Then, I switch the diverter valve to send the fuel to the injection pump. With it under pressure from the pump, I crack the bleed screw at the injection pump until solid fuel comes out. Then I tighten the bleed screw (while still under pressure) and then put the switch in the position for normal operation, i.e., to get its power from engine panel.

As for the on-engine lift pump, you do not need to remove it; simply disconnect it. Or, if for some reason it bothers you having it on there, you could remove it and fashion a plate to cover it. Those pumps are bad news because if/when the diaphram fails it dumps diesel into your crankcase. Also, the priming lever on it is a complete joke.

Definitely lose the primer bulb, no matter what else you do.

Here is the barb you need for the injection pump: Fitting Adapter 1/4" Hose ID Barb x 12mm or 7/16" Banjo Steel Zinc plated #DG | eBay

And this is the electric pump I used: Amazon.com: Facet-Purolator Fep60sv GOLD-FLO Fuel Pump: Automotive

And the diverter valve: FUEL VALVE SHUT OFF FUEL TANK 1/4" THREAD 18-1655 3 WAY VALVE WITH DETENT BRASS | eBay

Hope this helps.

Post sortie debriefing
 

Alan just got back from a Catalina trip, 13 hours of engine operation over the entire trip with absolutely perfect performance.

Very nice Neil.
I am wondering if the SPDT(single-pole double-throw?) could be a momentary switch instead to avoid idiots like me leaving it on.

And I'm sure it's explosion proof.

Sure, whatever is your preference.