fuel sending unit

Jcris

Chief Petty Officer
Joined
Apr 23, 2016
Messages
466
My boat has a standard swingarm type sending unit in the gas tank. I'm considering replacing it with a reed type sender.
I wonder if they are more or less reliable? Will the gauge on the dash have to be changed as well? The reed switch seems like a more durable/accurate design.I need to replace my tach on my instrument panel and began thinking about replacing all the gauges so replacing the fuel gauge wouldn't be such a big deal. Does this seem like a good idea? I want to re-carpet at some point but accessing the gas tank requires cutting the carpet. My current plan is to create an easily removable access panel for any future inspection of the tank. Is this overkill?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Because of the wide variation in "attitude" of the boat during operation, the actual fuel level in relation to the sender also varies. Therefore no gauge can be especially accurate except if the sender has been calibrated with the boat at rest and calibrated with a near empty tank. You know when the tank is full because you filled it. You want to know when it is empty or near empty. Anything in between is of no consequence. Regardless of the gauge/sender combination, never try to relate fuel gauge reading to gallons remaining. It is not a linear drop in fuel quantity. It is a drop in fuel "level". And since fuel tanks have unusual shapes this complicates the linearity as well. So my point here is use whatever sender you wish but if it works now, leave it alone as there is little to gain.
 

ajgraz

Lieutenant Commander
Joined
Mar 1, 2010
Messages
1,858
Creating good access (especially to the fuel tank) is never a bad idea.

Reed-type senders are absolutely more durable. Swing-arm types suffer from their contacts being exposed to whatever's in the fuel tank, greatly shortening their life.

Reed-types, unlike swing-arms, will move the needle on the gage in "increments" (rather than in a "smooth arc"), but I find them also to be less susceptible to wild swings as the gas sloshes around in the tank--especially if the sender is mounted close to the center of the tank.

So if I was you, I'd create that access to the tank you're talking about. Then later, when your swing-arm sender eventually fails, you'll be all ready to swap in a reed-type.
 

Jcris

Chief Petty Officer
Joined
Apr 23, 2016
Messages
466
Good advise gentlemen!
I'm always trying to reinvent the wheel. Make it better, or so I think. Just leaving things as they are seems the most difficult task. Geez!
I will add the access panel at this time and add the reed sender at some point down the road.
Thanks again
 
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