Fuel tank

[jerridsc]

Can someone tell me what each of the fittings are for on the top of the tank? I need to be sure. Thanks

[Ambler27FC]

Hope I am not mis-understanding your question, but a diesel tank will have:
1) a fuel supply line with pick-up tube going to the bottom,
2) a fuel return line,
3) a larger fuel fill line going to the deck,
4) a air vent line going to the top edge of the hull,
5) an electrical grounding point, and
6) a port for the fuel level transducer.

Can’t be sure, but the two in the top left of your picture look like fuel supply and return.

[LopezMike]

And the little elbow fitting I see on the upper right of the upper picture is probably the vent. The level sender is the doohickus on the center bottom of the upper picture.

[WillieC]

The vent is on the floor in your pic.
Fill is biggie.
Small supply is for Ebersprechensiesvedishspacher heater.
Larger supply for original engine.
Th Volvo Penta fuel returned to the filter, not the tank. Can’t speak for the AD engines.

The two supplies, top left, look to be same size. I am fairly certain the heater fitting in the WillieC is smaller, but it may have a reducer. Will check later this winter.

[Plum76]

WillieC, believe the AD21 also has fuel return to the engine-mounted filter assembly, rather than direct to tank.

My AD21 had been retrofitted with a filter return to tank, but not stock as far as I can tell, and only added because of an electric fuel pump. I've returned to the stock mechanical pump, so I'm deleting fuel return to tank.

Echo everything else, my plan is a filler neck, vent, fuel pickup and mechanical gauge on my tank, that's it. I'll plug the remaining (3) pickup sized holes. No heater in my boat..

Currently thinking about where to locate a new pre-filter/water separator, to replace old (and much larger) unit.

JP

The vent is on the floor in your pic.
Fill is biggie.
Small supply is for Ebersprechensiesvedishspacher heater.
Larger supply for original engine.
Th Volvo Penta fuel returned to the filter, not the tank. Can’t speak for the AD engines.

The two supplies, top left, look to be same size. I am fairly certain the heater fitting in the WillieC is smaller, but it may have a reducer. Will check later this winter.

[dkirsop]

I have two AD21 engines; one came with my boat and the other was originally salvaged from an Albin Vega sail boat. Both came fitted for a dedicated fuel return line which comes off the engine mounted fuel filter. On my boat the fuel return line is plumbed into the fuel tank but I cannot confirm if this was the original factory configuration. The injectors bleed excess fuel to the engine mounted fuel filter which in turn bleeds to the tank. I suppose the fuel return could be discharged into the suction side of the mechanical fuel pump, such as the intake fuel filter from the tank, or anywhere upstream of this point so excess fuel, and hence pressure, can be released back into the fuel tank and vented to atmosphere.

[Plum76]

Huh, that's the same way mine was routed, perhaps more original than I anticipated? My return line had been retrofitted with a valve to control the return line 'pressure', really just a way for the PO to account for the overfeeding he was likely getting from the electric fuel pump he had cobbled in.

None of the diagrams for this motor show a line coming off the filter housing as my setup is, so I had assumed it was a modification.

I assumed that the fuel return line to the filter was sufficient for the motor. If the filter element is tied back to a atmospheric pressure situation with the tank, doesn't that just rob available fuel from the injection pump? The return line to the tank can't tell if it's excess fuel from the injectors or fuel from the lift pump, so what's to prevent the lift pump from returning fuel direct to the tank via the filter housing, aside from any suction pressure from the injection pump?

I was going to plug this mystery return. When I swapped back to a mechanical setup this fall, I ran the motor on the new pump with the return line 'closed' via the ball valve that had been fitted. Seemed to do just fine, for the 1/2 hour I ran it. I did disconnect the prop shaft so that I could engage the transmission, heard that idling the transmission for too long is no beuno.

Jason

I have two AD21 engines; one came with my boat and the other was originally salvaged from an Albin Vega sail boat. Both came fitted for a dedicated fuel return line which comes off the engine mounted fuel filter. On my boat the fuel return line is plumbed into the fuel tank but I cannot confirm if this was the original factory configuration. The injectors bleed excess fuel to the engine mounted fuel filter which in turn bleeds to the tank. I suppose the fuel return could be discharged into the suction side of the mechanical fuel pump, such as the intake fuel filter from the tank, or anywhere upstream of this point so excess fuel, and hence pressure, can be released back into the fuel tank and vented to atmosphere.

[dkirsop]

Here is an illustration from my AD-21 instruction book for configuration of the fuel system. They definitely recommend a fuel return line to the fuel tank.

AD 21 Fuel System.jpg

[Plum76]

Is your setup with the banjo-style and tubing as shown? Mine was/is setup with a petcock style fitting to rubber fuel hose, with a brass ball valve fitted.

Interesting to see this diagram, thank you. Had assumed from other manuals and such that it was not a ‘factory’ arrangement. Even the replacement fuel filter housing from Albin motor doesn’t have a tapped return, leading me away from a vented housing.

https://albinmotor.se/en/albin-ad21/gro ... el-system/

Will have to track down a more elegant solution/remedy for this..

Jason

Here is an illustration from my AD-21 instruction book for configuration of the fuel system. They definitely recommend a fuel return line to the fuel tank.

AD 21 Fuel System.jpg

[Ambler27FC]

Well I learned something here. Seems like the safest bet is to trace the lines.

Kudos on the Ebersomethingsomething heater spelling.

Interesting idea to run the unused heated fuel back through the engine, but I do like the idea of the tank fuel being regularly scrubbed.

[dkirsop]

My fuel return does come off the filter holder through a banjo bolt connection. Here are a couple of pictures that show how it is arranged.

Engine - Front View.jpeg

Engine.jpeg

[Plum76]

Same fuel filter housing that I have in my 1970, guess I’ll reconnect as a return back to the tank.

My current pre-filter is located in the same spot yours is (though not as neatly), thinking about a different spot for the new one, to try and make it easier to drain and replace elements..

Thanks!

Jason

[WillieC]

Your pics of the AD21 ALMOST make me wish I had one. Or two.

[dkirsop]

Jason, this link on the Albin Motor web site will show a page with the various motors listed on the left hand side. Many of the manuals and instruction books can be found here for the various motors that Albin manufactured. Those listed for the AD-2 and the AD-21 will be of interest to you. The shop manual for the AD-2 is relevant to the AD-21 as both engines are similar and the AD-2 was the initial version of the engine so disassembly, assembly and repair procedures are the same.

https://www.albinmotor.com/AlbinMotor/e ... index.html

[Plum76]

Thanks, I've been reviewing these as part of my efforts to get back to a stock configuration, quite helpful. I don't think I'd seen your fuel system diagram before, hence my confusion on that one, plus the 'available' fuel filter housing not having a return port, I was led astray..

JP

Jason, this link on the Albin Motor web site will show a page with the various motors listed on the left hand side. Many of the manuals and instruction books can be found here for the various motors that Albin manufactured. Those listed for the AD-2 and the AD-21 will be of interest to you. The shop manual for the AD-2 is relevant to the AD-21 as both engines are similar and the AD-2 was the initial version of the engine so disassembly, assembly and repair procedures are the same.

https://www.albinmotor.com/AlbinMotor/e ... index.html