***Fuel sending unit question on 1975 32-2***

[Dagny]

Hello! Total newbie here but hoping someone might be able to answer this question about my recently acquired 1975 32-2 Hull #323 with a 3-cylinder Universal (?) Diesel:

There's a non-working fuel gauge by the RPM gauge and throttle, but I can't seem to find a fuel level sending unit anywhere on the top of the tank. There's only a wire coming out of a small hole on the top of the tank, but it's been severed. Does the tank have a fuel sender built in?

The first photo shows the fore end of the tank (taken from the access panel in the aft/port side berth).

The aft/starboard end of the tank only (second photo) has what I assume to be the fuel vent line coming out of it (in a T-fitting). Wondering why one line isn't enough?

Would appreciate any and all feedback!

Thank you!

Dagny

 

[Dagny]

MY ORIGINAL POST WITH A FEW NEW DETAILS!

Hello! Total newbie here but hoping someone might be able to answer this question about my recently acquired 1975 32-2 Hull #323 with a 3-cylinder Perkins Diesel:

There's a non-working fuel gauge by the RPM gauge and throttle, but I can't seem to find a fuel level sending unit anywhere on the top of the tank. There's only a wire coming out of a small hole on the top of the tank, split into two, but both of those wires have been severed. Does the tank even have a fuel sender built in? Doesn't appear to have any kind of mounting plate with connectors, simply a hole with some caulking/seal at the exit. By the way, it’s an orange-painted tank, appears to be steel.

The first photo shows the fore end of the tank (taken from the access panel in the aft/port side berth).

The aft/starboard end of the tank only (second photo) has what I assume to be the fuel vent line coming out of it (in a T-fitting, as you can see from the photo). Wondering why one line isn't enough? Why is it going in two directions, fore and aft?

Would love to avoid using the dipstick method to check my fuel level.

Would appreciate any and all feedback!

Thank you!

DE

 

[Frank Langer]

Dagny,
As nobody has replied yet, I will try to be a bit helpful, though I don't have complete answers to your questions.
I own a 1984 E30+, different boat from yours. I also have only 2 wires exiting from my fuel tank, and if I recall correctly, they both go to the fuel gauge. One of those got loose on our boat and the gauge began to read incorrectly, but worked again when I fixed that. The measuring gauge itself is inside the tank, not visible from above.
Most fuel tanks have a vent line that should exit outside the hull and be covered by a small screen fitting. Many engines also have a fuel return line that allows unused fuel to return to the tank. That may be the reason you have what appear to be two vent hoses.
Others may also comment, but that's my best info for you.
Frank

 

[Loren Beach]

The diesel will have a fuel line/hose going to the engine and a return line back to the top part of the tank. Also at the top or side adjacent to the top will be the outlet for the vent hose. All of the gauges I have seen do have a small hole in the top of the tank and either have a mechanical gauge readable on top, or two wires going from the top plate to a remote electrical fuel gauge.
Having a wire emerge from a little hole in top of the tank is a mystery to me. Hopefully others here can figure this out.

 

[Christian Williams]

Typical fuel gauge sender:

 

[Pete the Cat]

As others have noted, diesels have two fuel lines to the engine and they are both important. Diesels do not burn all the fuel (some fuel is used to cool and lubricate the injection pump) the fuel pump calls up and the excess is sent back to the tank in a return line. This line is important, though under low pressure. You may notice that the fuel tank warms up if you motor a long time because much of the fuel in the tank actually has cycled through the engine but not burned. It is an oddity of most diesels. And that is a Perkins with what looks like a BalMar large case alternator.

 

[tenders]

My 32-2 is gas-powered, but it had a painted steel tank (until I replaced it, the second time, and now use stainless), and the wire that connects to the tank near the fuel fill is a grounding wire.

Steel tanks, for me, lasted 22 years, sample size: 2. They conveniently rust from pinholes in the bottom, where you can’t see - you can only smell.

Mine didn’t have a gauge either, until I added one with the replacement tank. Barbaric, checking fuel with a dipstick, but you do get used to it. You don’t read about Columbus or Bluebeard complaining about it, so you? And with a diesel, do you check it more than once a season?

It isn’t as hard as you might think to pump the tank out, disconnect the fill, pull it out the lazarette, put in a sensor, and install a gauge. However, once you get the tank out, you might feel a need to replace it, which again may not be as expensive as you might think. But it would take an awful lot of dipsticking to make this project a good investment of time.

 

[Christian Williams]

We can also just fill the tank, then watch the Hobbs meter (the hour meter that goes on when the ignition does).

Fuel burn rate is reliable and the remaining contents of the tank easy to compute.

In general aviation, nobody stakes their life on a fuel gauge. Fuel burn is the standard.

Oh, and our tanks are odd shaped, which adds a guess factor to float senders.

 

[Dagny]

Dagny,
As nobody has replied yet, I will try to be a bit helpful, though I don't have complete answers to your questions.
I own a 1984 E30+, different boat from yours. I also have only 2 wires exiting from my fuel tank, and if I recall correctly, they both go to the fuel gauge. One of those got loose on our boat and the gauge began to read incorrectly, but worked again when I fixed that. The measuring gauge itself is inside the tank, not visible from above.
Most fuel tanks have a vent line that should exit outside the hull and be covered by a small screen fitting. Many engines also have a fuel return line that allows unused fuel to return to the tank. That may be the reason you have what appear to be two vent hoses.
Others may also comment, but that's my best info for you.
Frank

Thank you for all of the information and for replying so quickly, Frank! I've tested out the VDO fuel gauge and it appears to be working fine. It's the wire that's coming from the top of the tank that's the real mystery. More detective work ahead of me!

 

[Dagny]

The diesel will have a fuel line/hose going to the engine and a return line back to the top part of the tank. Also at the top or side adjacent to the top will be the outlet for the vent hose. All of the gauges I have seen do have a small hole in the top of the tank and either have a mechanical gauge readable on top, or two wires going from the top plate to a remote electrical fuel gauge.
Having a wire emerge from a little hole in top of the tank is a mystery to me. Hopefully others here can figure this out.

Thanks, Loren! You would think there would be a gauge, flange, some lugs, screws painted over? Anything, but not just a stranded copper wire sticking out of the top of the tank. It may just be a ground wire...

 

[Dagny]

Typical fuel gauge sender:

View attachment 48437

Yes! That's what I was expecting. However, nothing like that exists on my tank. Thanks, Christian!

 

[Dagny]

As others have noted, diesels have two fuel lines to the engine and they are both important. Diesels do not burn all the fuel (some fuel is used to cool and lubricate the injection pump) the fuel pump calls up and the excess is sent back to the tank in a return line. This line is important, though under low pressure. You may notice that the fuel tank warms up if you motor a long time because much of the fuel in the tank actually has cycled through the engine but not burned. It is an oddity of most diesels. And that is a Perkins with what looks like a BalMar large case alternator.

Something I never knew since I've never had a diesel before. Thank you so much for this important information, Pete!

 

[Dagny]

My 32-2 is gas-powered, but it had a painted steel tank (until I replaced it, the second time, and now use stainless), and the wire that connects to the tank near the fuel fill is a grounding wire.

Steel tanks, for me, lasted 22 years, sample size: 2. They conveniently rust from pinholes in the bottom, where you can’t see - you can only smell.

Mine didn’t have a gauge either, until I added one with the replacement tank. Barbaric, checking fuel with a dipstick, but you do get used to it. You don’t read about Columbus or Bluebeard complaining about it, so you? And with a diesel, do you check it more than once a season?

It isn’t as hard as you might think to pump the tank out, disconnect the fill, pull it out the lazarette, put in a sensor, and install a gauge. However, once you get the tank out, you might feel a need to replace it, which again may not be as expensive as you might think. But it would take an awful lot of dipsticking to make this project a good investment of time.

I think you may be right, tenders. I can probably force myself to use the dipstick, at least for now. Once I change out the old orange-painted steel tank (original?), I'll probably install a proper impedance-measuring fuel sender. Thanks for the advice!

 

[Dagny]

We can also just fill the tank, then watch the Hobbs meter (the hour meter that goes on when the ignition does).

Fuel burn rate isreliable and the remaining contents of the tank easy to compute.

In general aviation, nobody stakes their life on a fuel gauge. Fuel burn is the standard.

Oh, and our tanks are odd shaped, which adds a guess factor to float senders.

Thank you, Christian. Measuring burn rate sounds like it would be the most accurate. Only thing is, that depends on the throttle/RPMs, and I'm rarely ever consistent with my throttle. Just depends on the wind, currents, and so on...

 

[tenders]

My actual advice is: either wait until the tank is leaking, then replace it with one that has a sensor in it, or decide to replace a still-functioning tank at a convenient time of your choosing, under the theory that it is on borrowed time anyway, and then replace it with one with a sensor in it.

 

[Christian Williams]

Fuel burn averages out. It is reliable no matter how you use the boat.

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