# Fuel gauge sender broken...



## philthefish (Aug 10, 2009)

Hi folks,



I'm starting to put some TLC into my boat. She's earned it after her Rookie season of me and Russian beating on her, thanks to tips from the PFF. The background. 225 1997 Evinrude Ocean Pro on a 1997 24.5 hydrasports WA. OMC gauges.



I've got a fuel-gauge that always reads shy. The sender on the tank also has a gauge and that one also reads bogus. Shorting the leads to the console gauge results in a Full tank reading, so I'm inclined to believe it's the sending unit inside the tank.



I'm not quite sure what I'm in for, but I don't want to pull the sender without knowing (mostly) what I'm doing. I've attached a pic of the sending unit/tank gauge for any tips from you pros out there. 



My hunch is to yank the sucker and replace it with something like this here:



http://cgi.ebay.com/ebaymotors/ws/e...1ffe77978&rvr_id=&ua=M*F?&itemid=130280424190



Tips/comments/insults?


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## Sequoiha (Sep 28, 2007)

You can replace it with the kind you have, or you can up grade,, which ever you choose, loose those connections you currently have,,, they are not water tight, or corrosion resistent,,, If you can pull yours out and bring it up here, i can fix you up with several options.


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## Breeze Fabricators (Oct 2, 2007)

Be sure your batteries are disconected before you pull it. If it sparks while the sending unit is out it may blow the floor out of the boat. Don't reconect the batts. until the new sending unit is bolted and sealed in place:usaflag


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## sosmarine (Sep 28, 2007)

> *Breeze Fabricators (11/22/2009)*Be sure your batteries are disconected before you pull it. If it sparks while the sending unit is out it may blow the floor out of the boat. Don't reconect the batts. until the new sending unit is bolted and sealed in place:usaflag


Tim,

Good advise, but I hope you aren't speaking from first hand experience.


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## X-Shark (Oct 3, 2007)

I would not use the one you have a link to. It's pretty much the cheapest sender you can buy. They make the fuel gage needle bounce.



I recommend the Hardin units. no Moving parts. You must cut them to the proper length and it needs to be done so as not to deform the outer tube. I can help you with that if you need help. I have a tool to make this quick work.



A small insulator will be removed from the piece you cut off and reinstalled in the end of the tube.



This will insulate the outer tube from the wire in the middle.



http://www.hardin-marine.com/detail~ID~64.aspx



If you are unaware ........Sending units are indexed with the 5 holes. The unit will only fit 1 way. The 4 others will be incorrect.



The reason for this is so the sending arm/ float arm does not hit the side of the tank or a baffle.



There is no float arm on the model that I recommend, so it wouldn't make any difference as to which way it is orientated....but it does as to the holes lining up correctly.



Clean the tank well before you remove the sender to keep crap from falling in the tank. Then use a Sharpie marker to make a witness mark on the tank and sender.



Once the old sender is out, lay the new gasket on the tank and align it properly with ALL 5 holes. Now mark the gasket to match the mark on the tank.



Remove the gasket. Now align the gasket with the holes on the new sender and make a mark on the new sender.





Now you ask why this is all necessary? Believe me it will save you a BUNCH of time. Usually it is hard to see if all the holes are aligned correctly when your working down thru a piehole that is not centered directly above the sender. It could be even worse on some boats that I've done.



With the Sharpie witness mark you know exactly which way the thing will align. No guessing at 4 other ways.



And YES Please disconnect the battery before you start any of this. We don't want to be reading that they hauled your ass to a burn unit or worse.


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## Breeze Fabricators (Oct 2, 2007)

I wasn't the victim but I was the first responder. All the hair was burned of his face and the newly glassed in deck was blown off the boat. The blowie (person who was blown up) made a 30 ft. trip in the air from the boat and to the ground!!! He was fine after the hair grew back.


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## Mullethead (Oct 4, 2007)

Do you all use any gasket sealer, and if so what type? 

I have had a heck of a time getting a leak-free seal around sending units. With aluminum tanks - and threaded fateners 

And do not use any silicon based sealants (learned this on the hard way) dispite the label saying "oil & gas resistant" 

Keith


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## philthefish (Aug 10, 2009)

Hi guys,



Thanks a lot for the advice. I'd hate to replace this with another crapper sender, so I will look for a hardin. And I will disconnect the batteries even though they are behind a kill switch (actually as 1,2 toggle + off). 



Question, is there a 'uniform' mount for these units? The sender has an odd arrangement of 3 small screws that hold it into the tank flange. The flange itself is mounted with about 8 bolts symmetric around it. I definitely don't want to be tapping new holes in the tank. But from X-Sharks excellent description, it sounds like I should just yank it (marking it clearly on the tank before doing so). 



I'm guessing my tank is 24" deep, it's a 115 gallon. 



Much obliged again guys, stay tuned. 



Phil



P.S. Any of you local guys have hardin units?


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## sosmarine (Sep 28, 2007)

PM sent


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## X-Shark (Oct 3, 2007)

> Do you all use any gasket sealer, and if so what type?






I use the old Permetex #1 hardening sealer. It has done well when I've needed to pressure test a tank.



Coat both sides of the gasket.





> Question, is there a 'uniform' mount for these units? The sender has an odd arrangement of 3 small screws that hold it into the tank flange. The flange itself is mounted with about 8 bolts symmetric around it.




Yes there is, but your description sounds weird.



The norm is a 5 fastener holes. They are laid out so the the sender only will fit one way. So they are NOT uniformly laid out.


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## philthefish (Aug 10, 2009)

Hi guys,



Well I took advantage of some of this gorgeous weather to put in some more time today. After cleaning the tank (and removing my leaky portal, which also needs replacing) I decided to try and remove the gauge itself. I mentioned before it was held in by 3 screws, which was incorrect. Only two small stainless screws held in the tank gauge to the tank flange, which indeed had 5 bolts in it and 1 oddball screw.



After soaking the screws in WD40, I gently tried to back them out. Both heads popped off due to corrosion! Bummer. I thought I might be able to pry it out and to my surprise, boink, it popped out. Turns out that my sender here is *magnetic*. No wires down in the tank at all! 























Ok. Well, next up, clean the tank flange and what remains. So I did that, soaking everything in WD40. Now, note that there is one odd-ball screw in the tank flange. It looked like it actually goes down into the flange, or at least orients the sender in only one way (as X-shark helpfully pointed out). Tried backing out that screw and POP, damn, another screw head. 



So, here's what's left. The tank flange. (In this pic, the odd-ball screw is still there...the head is now, sadly, gone)














My question next is, am I going to get this sucker out by taking out those 5 bolts or did I screw the pooch by breaking off that odd screw. I shudder to think that that screw tap needs to be drilled out...think of all the crap that will fall in the tank.



So, I'm not going further until a) that WD40 soaks more into those tiny bolts and b) y'all give me the ok that this should be doable. 



I'm going to order the Hardin part today... I don't know the depth of my tank, but I reckon it can't be deeper than 24". It's 115g.



Thanks again...sorry about the pix, my cell takes sucky ones... Hope you all have a good turkey-day.


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## X-Shark (Oct 3, 2007)

I haven't seen a flange quite like that one with that odd Phillips screw, but my thinking is that it is there only to help with the orientation.



Use a 6 point socket on a 1/4in drive ratchet to remove the other screws.



I bet where the screw that broke off will not be a problem if it is flush with the surface of the tank.



The new gasket and sending unit flange should cover and seal that screw.


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## philthefish (Aug 10, 2009)

Awesome. Thanks X-S, that's what I was hoping. I've got a 6-point 1/4 inch socket, but on some of the bolts it does not quite fit between the flange and the head of the bolt. I've decided I'm just going to shave it down a bit...the alum is pretty soft.


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## Sequoiha (Sep 28, 2007)

that philips screw is a bonding screw,, that is where the bonding wire from the aluminum tank, to the filler neck to the ground lug on the battery should go.. if there is not one there put one there, use a green 10 or 12 gauge wire with sealed connectiions...


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## philthefish (Aug 10, 2009)

Hi Seq,



I failed to mention that just a few cm from the gauge on the tank is a bit fat tabbed ground connection to the tank. It's actually got three wires to it, 2 are thick green and one appears to be a raw copper lead. All grounds no doubt. So this would explain why that screw had nothing attached.



When I pulled the tank gauge, there was a TON of salt, sand and general crap underneath it. No doubt this affected it's ability to read true, but just how much is the question. Just for sh*ts and giggles I'm going to reconnect it and see if I get a better reading. I know my tank should be 1/4 full. 



Ok, back to tending to turkey.


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## philthefish (Aug 10, 2009)

Well a quick update. I realized that eventually I was going to have to fill up the boat in order to calibrate the new sending unit when I got it. And I wanted to see if I could actually isolate the source of the current failure. 



So the unit I actually have is this one: http://www.rochestergauges.com/Pages/PDFs/6700.pdf



It's pretty clever how it works...As stated, the top magnetic gauge seemed to work fine when I fired up the engine and manually spun the magnetic sensor with a fridge magnet. So upon cleaning the fitting (full of salt and crud) I set it back in and filled the tank. And, no surprise, the magnetic arm w/float in the tank must be the problem. I only registered < 1/3 tank...



The next step is to yank that float and replace the sending unit. Will post my results. Thanks for the help again guys.


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## Sequoiha (Sep 28, 2007)

Glad you got it diagosed,, good luck on the repair,,, let me know if you need any parts.. forum member get a 10% discount...


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## philthefish (Aug 10, 2009)

Hi again,



Well I bought myself a late christmas gift and picked up the Hardin 2 wire sender. It's a nice unit. I bought the 24" model and trimmed it to 16.5" with a pipe cutter. Was very easy.



My next task is to calibrate it to an empty reading. Strangely, I can't get a reading on this sender with my VOM *any more than I could the other sender. * There is clearly some magic involved in these circuits when combined with the gauges...I'm stumped as to why I can't get a reasonable ohm reading out of a sender when it's outside of the boat.



I'd rather not schlep the batteries outside just to recalibrate this sucker... How can I jimmy a circuit to get a proper reading between 33-240?



A google search provided very little help...It seems raw auto float units can just be wired to the VOM, but not these other devices.



Any suggestions? 



Emerald, I need to come by and see you guys can buy some parts for this guy also. It looks like I'm going to need 1" flange bolts and I'm sure the ones I've got in there now are not more than 1/2".



Phil


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