am I missing something or did they put the wrong length sending unit in my new tank?

[weider1717]

paid near 500 bucks for a new 25 gal. aluminum tank..was $100 to ship it so like 400 for the tank.

the depth of the tank is 5 7/8" and the sending unit which is a wema says 4.5 on the top of it indicating to me it's 4.5" long...

today I wired it up ad put 12 gallons in (stopped at 6 gal even at the pump in each of my 6 gal jugs) so i'd know that I had exactly 12 gals and I poured both into my tank.

and the gauge when i turned the key BARELY budged off Empty.....

IMO they needed to have installed a 5" sending unit thats what my old one looks to be which is more of the old swing style looking float it's a medallion instruments sending unti the old one.


anyway with the tank being 5 and 7/8" depth wise did they do right by putting a 4.5" sending unit or is it too short to accuretly measure the gas in there?

I don't want it showing empty when I have 10 gal left in it!?

your op's?

 

[weider1717]

Re: am I missing something or did they put the wrong length sending unit in my new ta

if you guys think the same maybe I can call them and get them to send me a 5" one.

 

[Silvertip]

Re: am I missing something or did they put the wrong length sending unit in my new ta

Don't go by the number on the sender -- measure it. If the float doesn't get near the bottom of the tank there is no way it can accurately measure the fuel level. Look at it this way. If the tank is 5.875 inches deep and the sender is 4.5 inches long, that's about a 20% error. It will be accurate when full but nowhere near accurate when empty. Have them send you the correct sender.

 

[weider1717]

Re: am I missing something or did they put the wrong length sending unit in my new ta

I agree! but I'm 99% sure the 4.5 on the top of the send means it's 4.5" long.

and on wema's site it says a metal tanks sender needs to be .75" shorter..they have me 1.3" shorter.

I am def. gonna call them tommorow. It's a wema model SSS and says 4.5 on it so like I said pretty sure it's 4.5" long.

 

[FlyinGuy1017]

Re: am I missing something or did they put the wrong length sending unit in my new ta

IMO, there is only one time when I care that a gas guage is accurate...when it's empty. I always calibrate mine so that they show zero when it's acutally zero. Use that as a baseline and the rest is easy.

 

[weider1717]

Re: am I missing something or did they put the wrong length sending unit in my new ta

thanks for the replies sounds like u guys agree.

with that said with the tank being 5.875" deep according to the blue print I have in my hand this very sec...should I request them to send me a 5" or a 5.5"?

wema's site says for a metal tank they recommend .75" clearance between the tank and the bottom of the sender...with that thinking a 5" would be pretty dead on their advice..or should I ask for a 5.5"?

also think i will have to send them this one back before they send me the new one? hopefully they will send the new one on at no charge..I don't mind sending this one back but I don't expect to pay for the new one or for them to wait until they get this one back before they send the new one...it's gettin warm weather I was gonna launch mine friday and run it a little and dock it.

thanks

 

[Silvertip]

Re: am I missing something or did they put the wrong length sending unit in my new ta

With a 5 inch sender it would still be 7/8 inch off the bottom and therefore still very inaccurate as soon as the fuel level begins to drop off full. A 5.5 inch would provide the best EMPTY ready and would rest 3/8 inch off the bottom. As long as it doesn't touch the bottom of the tank it would be ok.

 

[Silvertip]

Re: am I missing something or did they put the wrong length sending unit in my new ta

If the bottom of the float extends past the end of the sender then a 5-inch would work as it would put the float very close to the bottom of the tank. If the float does not extend past the bottom of the sender it would still be 7/8 inch off the bottom of the tank and therefore would still be very inaccurate as soon as the fuel level begins to drop off full. A 5.5 inch would provide the best EMPTY ready and would rest 3/8 inch off the bottom. As long as it doesn't touch the bottom of the tank it would be ok. But use a 5-inch if the float extends past the end of the sender or a 5.5-inch if it doesn't. That's my story and I'm stickin' to it. With this scheme, "Empty" will mean EMPTY. Good luck.

 

[joed]

Re: am I missing something or did they put the wrong length sending unit in my new ta

Was the boat sitting level? Where in the tank is the sender located?
If the sender is near the front the and the boat was tilted backwards the reading would be way off not matter what sender.

 

[weider1717]

Re: am I missing something or did they put the wrong length sending unit in my new ta

If the bottom of the float extends past the end of the sender then a 5-inch would work as it would put the float very close to the bottom of the tank. If the float does not extend past the bottom of the sender it would still be 7/8 inch off the bottom of the tank and therefore would still be very inaccurate as soon as the fuel level begins to drop off full. A 5.5 inch would provide the best EMPTY ready and would rest 3/8 inch off the bottom. As long as it doesn't touch the bottom of the tank it would be ok. But use a 5-inch if the float extends past the end of the sender or a 5.5-inch if it doesn't. That's my story and I'm stickin' to it. With this scheme, "Empty" will mean EMPTY. Good luck.

I agree that would be the most accurate route..However, on wema's site they recommend on a metal tank a clearance of .75" between the sender and the tank.

I assume because that gives you plenty of reserve...the original sender I took out of my old tank was 5"

gah u got me wondering if I shoulda told them 5.5" instead of 5" I called the maker of my tank today and they was very nice and said they would send me a 5" wema and for me to ship back the 4.5" they said they put the 4.5" one in for plenty of reserve.

so as of right now I am supposed to receive the 5" wema on tuesday...anyone else think I shoulda told them 5.5" instead?

what to big boat manufactuerers usually do? how much room do they usually leave between tank and sender?

thanks!

 

[Mark42]

Re: am I missing something or did they put the wrong length sending unit in my new ta

WEMA senders do not work like regular senders. Just CALL wema and ask for customer service. They will give the the correct info, and they will tell you what the deal is with exchanging the sender.

Also, belly tanks are horrible for trying to get an accurate reading from just due to the nature of their design. A long, shallow tank that sits at an angle when the boat is under way. The tank can be 1/3 empty, and the sender will be pegged to the top of the tank.

 

[Silvertip]

Re: am I missing something or did they put the wrong length sending unit in my new ta

I hate this "reserve" business especially when you have long, shallow, wide tank that one minute has fuel at the back, then level, then at the front. You should check the fuel gauge when the boat is stopped and reasonably level. That reading will be your reference. If the gauge stops bouncing around when under way you know the fuel level is getting low. As was pointed out, depending on the tank shape, there is no way to get an accurate reading under all conditions regardless what type of sender you have. Reserve means no actual gauge reading so you are now guessing how much fuel you have. I only want to know when it is actually empty or approaching that point. In reality, I never let my fuel level get that low but some people simply don't like to fill up so they run with marginal fuel loads.

 

[weider1717]

Re: am I missing something or did they put the wrong length sending unit in my new ta

another reason fo the gap according to wema is that the tank flexes under use with waves etc...and they say u need about a .75" gap or the sender will hit the tank..

not sure if i agree with that? but..thats what they say.