Fuel Tank Sender

Suzook

Has anyone out there R/Rd (remove/replace) there fuel tank sender on a FD 202 GS?  Or experience in general in this task, is it worth my time and aggravation to do it myself or leave it to the pros?

HydroCanis

Don't know but assume it wouldn't be much different than a 217, assuming there's an access hole above it. I pulled mine out because I thought it wasn't working (but it was). Pretty easy to remove and replace. Only complication I'd expect is if you need to adjust a new one for tank depth.

Suzook

Thanks for the reply, glad yours worked out.  So, did you end up replacing the gauge?  I'll be checking the fuel level issue today prior to installing my new Faria combo fuel/volt gauge, due to a previous issue with the volt side. 

HydroCanis

No, the issue for me is nonlinear indication of fuel level. That is, the gauge reads near-full for the first 20 gallons of usage and only then begins to fall more than a tad. It could be that the gauge isn't working correctly, but it does fall all the way to E when the tank is empty. So I don't assume I have 3/4 of a tank when it reads 3/4, but I know that 1/4 means I'd better be thinking about fueling it up pretty soon.

cjjjdeck

Here is a post from an iboats (another forum that gives great information) forum member, Silvertip, who has a strong electrical background.  It's his response in how to check a fuel tank sending unit:

Silvertip

Supreme Mariner

#7

September 20th, 2011, 11:21 AM

Re: Fuel level sending unit test

The vast majority of U.S. fuel tank senders have a resistance range of 30 - 240 ohms. 30 ohms = full, 240 ohms = empty and approximately 109 ohms at 1/2. You do not need to remove the sender or even access it to measure the resistance. Disconnect the pinp wire from the "S" (send) terminal on the back of the gauge. Using your multitester (ohm meter) meausre the resistance from the pink wire to ground. If you know roughly how much fuel is in the tank, you can determine what the approximate resistance reading should be. If you don't know and want a more precise check, then you need to pull the sender and move the arm through its travel while watching the meter range from 30 - 240 ohms. 10% error in the readings can be expected and would be considered normal.

Another check is to make sure the floats actually float. If they are fuel soaked and sink they cannot make the gauge register correctly. If the float arms are misadjusted readings can be wrong. You cannot make the gauge read spot on when full, empty and anywhere in between. So calibrate the sender so the gauge reads empty with an empty tank. You know when the tank is full because -- well -- you filled it.

Ensure the senders are the correct length for the depth of the tank. Too short they read empty before the tank is empty.

I also attached a basic wiring diagram and a instruction sheet in how to adjust a replacement sender for tank depth from Moeller Marine.

Hope this helps.

 

bshippjr

David, my unit acts the same way.  It stays near full or 3/4 for a long time, then drops to about 1/4 tank.  With 52 gal capacity, I just add gas when it drops to 1/4.

My boat stays on lift at marina and I am one that fills up near end of season.  Was full last November, but first time out this year when I left slip the gauge registered 1/4 so I headed to gas dock.  Only took 9 gal so I assumed sending unit issue, but all has been fine since. 

Suzook

Message traffic/interest is much appreciated.  So, Faria sets resistance values @ 33.5 - 240 ohms for America.  I checked the fuel side of old combo gauge as previously suggested digital meter read 29.1 ohms with the gauge reading full (pegged), pretty darn sure tank isn't.  Installed new gauge and it is no longer pegged, up side my volt meter is working as advertised.  Pulled the deck plate behind the captains seat and found where fill hose attaches to the tank.  Anyone have thoughts on accessing a sender just behind the ski pole .... oh yea this is gonna hurt!

HydroCanis

That does sound like a difficult location.

Something else I found when I had the sender removed... I had used about 10 gallons of fuel (of 64 when full), and when I removed the sender, the fuel level was at the top of the tank. I siphoned out at least another 5 gallons and only then did the level in the tank begin to fall below the top. I probably overfill, as I can't tell when it's full until I hear sloshing in the filler neck, so that would account for some of it. The boat on the trailer wasn't quite level, so that would account for some of it. But there seems to be some sag/expansion of the tank going on. I think the weight/pressure of a full tank enlarges the tank itself a little. Plus the temperature of fuel in the ground is usually lower than it is after it sits in the tank in the sun for a few days, so the volume of a given mass of gasoline does increase a little (sounds like about 1% from mid-60F to mid-80F). If I've misinterpreted something please feel free to correct me!

bshippjr

David, do you have a special tank on your 2003?  I have brochures from 2000 and 2005, and they both show the tank capacity on an SD 217 at 52 gallons.  I don't believe I have ever put in more than 35 gal (the cost of which about gave me a heart attack).

HydroCanis

Apparently I do. I saw what I thought was a 2003 brochure that said 52 gallons. I don't know if it was specially ordered that way or what. The seller and I ran it dry during our test (fortunately near the ramp). Because of the gas station pump limits for plastic, it took me two credit cards plus more cash to fill it, almost exactly 64 gallons. I hope I added it up right! Seller said it was 64 and I sort of doubted him, so I paid attention to how much I put in it.

Suzook

Hydro, ditto on everything you posted.  The boat is in the sun (95 deg), on a slight hill, and boat not level on trailer. Currently waiting on a new speedo gauge then the wife and I will be WOT to burn off enough fuel to see if in fact I might actually have a functioning sender.  Thinking I may have to remove ski pole assy if it is bad.

HydroCanis

Hope that it in fact works. I'd install a FloScan tomorrow if they didn't cost so much.

Suzook

Thanks for the positives and I hear you on the FloScan, but then again what's a boat other than a hole in the water to throw money into.  Sorry, been waiting for the opportunity throw that out there.  So, received my speedo and just waiting for the t'storms to clear so I can install it.  Hope you have a great 4th of July.

Suzook

So, finally getting around to a follow-up and, yes the fuel gauge is installed and working in that it bounces around between 3/4 and a 1/2 tank.  However, I've done a lot of boating to get to this point and still have no idea what the actual reading is.  Will probably run out of fuel the next trip out, ha!  As the weather cools will start thinking about attempting to R&R the sender, or have another beer and put it off till spring.

HydroCanis

Looking forward to hearing how it works out while I have another beer.

HHP123

I have a 1998 240 fundeck w/ a 66 gallon tank in which I replaced the sender.  There is an 6" access hole in the floor, (sole?), above it, but not quite in line.  What I am saying is that the unit is not directly under the access with little room to get at it.

My boat has a poly tank with the mounting ring for the sending unit molded into it.  I used a universal gauge which has an adjustable arm for tank depth.  The mounting flange on mine has asymmetrical screw holes in it which means you need to note the direction of the arm when you remove the old one.  I did not, and went ahead and installed the new one and it read it empty with the tank filled to the max.  The float was pressing up against the side of the tank, which you can't see or feel during installation.

After I sorted that out it worked fine but was pretty frustrating.  BTW, the earlier post re: resistance are correct and helpful.  You can connect the wire to the new  sending unit to a VOM or gauge,  and move it through its travel and see the change values.  It was a knuckle buster for me, but worth it.

If fate has provided easy access to your unit you can use a mechanical reading float gauge.