The Boating Forum - Mercury Smartcraft fuel calibration

THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.




me00351
05-06-2012, 06:47 AM
The manual describes a method for calibrating the fuel gauge for irregular shaped tanks .You begin with an empty tank, then add fuel 1/4 tank at a time until full .
Is there a way to do this without starting with an empty tank?


fshmn
05-06-2012, 07:39 AM
I hope you find out. and if you do follow that proceedure, I'd appreciate a PM letting me know how it worked out.

I already had 70 gals in each tank when I installed those gauges. So, I opted for listing the tanks at 100 gal and then reset them for a full fill up when I topped off my tanks.

The problem I have is the smartcraft gauge is now inaccurate. I have a fuel mangement gauge that tells me how much I have used. It is very accurate. but the smartcraft gauges will show 100% until I have used about 20 gals on each side. When it shows 60% (which should be 60 gals) My fuel management gauge is telling me I have only 40 gals left. The fuel management gauge is correct, the smartcraft gauge is not.

So, if you do the empty, 1/4, 1/2, 3/4, full routine, I'd sure like to know it it turns out more accuate on the smartcraft "fuel left" gauge.

Glen E
05-06-2012, 08:02 AM
if you are rectangular....
http://www.veradoclub.com/smf/index.php?topic=6191.0


me00351
05-06-2012, 10:00 AM
I'll send the inquiry to Mercury to see what they say since my tank shape is irregular.
Starting with an empty tank is the main problem since none of us have an empty tank unless we run out .
It seems that there could be a way to fool the electronics since the "fuel used " system is very accurate . Maybe using the voltage readings from the sender at the quarter tank levels could be applied for calibration.

me00351
05-08-2012, 04:07 AM
This is the response from Merc :


Thank you for contacting Mercury Marine Customer Service. The recommended procedure for calibration of the fuel tank is written in the SC1000 manual. This is the only Mercury recommended procedure. Another option is to have a dealer calibrate the tank for you or use the remaining fuel before calibration.

I was hoping for a more imaginative reply since there are lots of problem solvers that work for Mercury. I'll call them to see if there's an engineer type person who can help.

divefreak
05-08-2012, 04:17 AM
So, if you do the empty, 1/4, 1/2, 3/4, full routine, I'd sure like to know it it turns out more accuate on the smartcraft "fuel left" gauge.

It is a lot more accurate! :thumbsup:

´But you have to start from an Empty tank and a level boat!

divefreak
05-08-2012, 04:20 AM
Another option is to have a dealer calibrate the tank for you


And we as a dealer do nothing else than drain the tank and refill it following the procedure described in the manual.

there´s no magic trick to do it;cool;

Glen E
05-08-2012, 05:18 AM
This is the response from Merc :



I was hoping for a more imaginative reply since there are lots of problem solvers that work for Mercury. I'll call them to see if there's an engineer type person who can help.

you are asking them to skirt their recommended procedure and tell you "on the sly" how to do it?


That won't happen.......

thumperlove
05-08-2012, 05:30 AM
Yes there is a way. Our Merc Monitors were Callibrated in KW with 3/4 fuel. Problem is I didn't do it:/ My fraternity brother used to be a VP in the Smartcraft division at Merc. He sent me the gauges, then flew to KW to dive with us for a few days and did the install and calibration. He even changed the fuel gauges to show gallons and not % remaining. My friend left Mercury last year tho (great job at Livorsi).

bradv
05-08-2012, 05:59 AM
pull your sending unit measure and mark your sending unit every 1/4 then just move it along with the calibration on the screen then put it back in. works like magic.

Glen E
05-08-2012, 06:54 AM
pull your sending unit measure and mark your sending unit every 1/4 then just move it along with the calibration on the screen then put it back in. works like magic.

And this is exactly what the thread says above from the club. In thinking about it, I don't see how it matters if it's rectangular or not because that sender only moves up the stick a certain way, and that is up-and-down. So marking it like Brad says above and I say in my thread seems to be the "trick" way to do it

And changing from percentage to actual is not actually a trick, as soon as tell it how many gallons are in the tank, it automatically switches from percent to actual, as the float on the stick can now tell what half of a certain amount is, instead of just 50% of travel.

SaltyG
05-08-2012, 08:35 AM
Bradv & Glen...pulling the sending unit and marking it every 1/4 will still only work for a rectangular standard tank. If it is deeply v shaped or some other shape, the bottom quarter or half of the tank may only be a few gallons. The only way to really do it is to empty the tank dry, know how much gas the tank holds. Put in 25% at a time and set the gauge. This way, the gauge will do some linear math on the ohms reading and try to better estimate at the 1/4 percent true fill readings might be at non quarter places on the sending unit due to the odd shape of the tank. So to get it right, he still has to empty and fill the tank.

me00351
05-10-2012, 04:44 AM
My initial call to Mercury provided me with the verbal equivalent of the owners manual. I'd like to find out how Thumperlove's friend calibrated his without emptying the tank.

divefreak
05-10-2012, 05:00 AM
My initial call to Mercury provided me with the verbal equivalent of the owners manual. I'd like to find out how Thumperlove's friend calibrated his without emptying the tank.

he pulled the senders.... and moved them manually .:grin:

thumperlove
05-10-2012, 06:04 AM
I sent him a text with a copy of your question.

Glen E
05-10-2012, 06:27 AM
he pulled the senders.... and moved them manually .:grin:

Exactly .....

Flatout71
05-10-2012, 07:07 AM
Bradv & Glen...pulling the sending unit and marking it every 1/4 will still only work for a rectangular standard tank. If it is deeply v shaped or some other shape, the bottom quarter or half of the tank may only be a few gallons. The only way to really do it is to empty the tank dry, know how much gas the tank holds. Put in 25% at a time and set the gauge. This way, the gauge will do some linear math on the ohms reading and try to better estimate at the 1/4 percent true fill readings might be at non quarter places on the sending unit due to the odd shape of the tank. So to get it right, he still has to empty and fill the tank.

This is correct. I have done it both ways. The Sender out of the tank trick is only good for rectangular or square tanks. :thumbsup:

bradv
05-10-2012, 07:13 AM
Well its quicker and easier than sitting at a gas station to do it the other way and its close enough. Its also going to be affected if u do it on a trailer vs in the water bc it won't be sitting the same way. And then if the boat is loaded heavier one day so the cg is off from when u did the calibration. Screw it there's no way to have it precise just sink the boat

bradv
05-10-2012, 07:15 AM
Ok last option n2k into chartplotter and manually add fuel everytime u add fuel and it will subtract based on fuel burn and then u don't have to rely on sender

thumperlove
05-10-2012, 07:19 AM
Are we trying just to get the guages calibrated to show an estimate of the % left in tank? Why not just zero the burn each time you fill up. That is the only way to really know. Our guages dont show % anymore, they show the full amount for each tank (100, 275, 100) and give an estimate of the remaining. But its not exact.

fshmn
05-10-2012, 07:41 AM
Ok last option n2k into chartplotter and manually add fuel everytime u add fuel and it will subtract based on fuel burn and then u don't have to rely on sender

The OP and I have had some conversations on the matter and we both do what you have suggested.
I am using a Lowrance LFM-200 to keep up with how much fuel I have used and have left. It has been very accurate based on fill-ups
I belive the OP has a similar system.
We are both interested utilizing our "gauges" for backup assurance. I'm sure someday an electrical gremlin will knock my LFM out and I'll be in the dark as how much fuel I have left. Leading to a quick trip to the fuel supply monster.

bradv
05-10-2012, 10:34 AM
ok so you and the op dont want to sit there and dump fuel in the boat but also dont want to do it the cheater way and want us to make something magical up for you that levitates the float to the exact position and be dead on accurate? have you ever used a sending unit on a boat? i just leave my sending unit 2 inches above the bottom of the tank that way if im ever a dumbass and dont realize its on empty i still have a fair amount of fuel to hopefully make it back.

fshmn
05-10-2012, 12:17 PM
ok so you and the op dont want to sit there and dump fuel in the boat but also dont want to do it the cheater way and want us to make something magical up for you that levitates the float to the exact position and be dead on accurate? have you ever used a sending unit on a boat? i just leave my sending unit 2 inches above the bottom of the tank that way if im ever a dumbass and dont realize its on empty i still have a fair amount of fuel to hopefully make it back.

well, not exactly. Ive been doing fine with my setup the way it is. The only thing I never wanted to do was drain the gas out of two 100 gal tanks, just to calibate the gauge to be "more" correct.

When the OP posted, I only chimmed in to show there was someone else interested in a solution to the gauge being inaccurate.

I had never thought about pulling the sending units out and trying to calibrate it that way. And Im still not sure it is worth the effort to do that for what it might result in. Too bad I didnt try it last year when I put in new sending units.

Truth be told, yep, I thought it would be kind of interesting if someone more knowledgeable replied with....."There is a magical trick that Mercury didn't tell owners about that helps calibrate your fuel gauge more accurately. All you have to do is push button A twice, then button B once, honk your horn and shift it into reverse". Have you ever had to reset something on a GM car?

But so far, no one has suggested such an "easy fix" to a minimal problem.

Im OK with what I have. Re-fill at 40%. Rarely travel over 60 miles. Doubt Im ever going to run out of gas. I was just curious as to suggestions from someone who might be in the know.

SaltyG
05-10-2012, 12:46 PM
I agree with Bradv and thumperlove and it seems that is what you do anyway...use your N2K fuel burn numbers on your charter plotter and add gas to the plotter as you fill up. It is the most accurate. You just have to remember to always have your chartplotters on.

Yeah, unfortunately, no such magic trick to reset things, like on a car. I think to turn off my seat buzzer I had to turn the ignition on and off 9 times, hit the brake 3 times, open the door lock and push the seat belt button to activate the magic code to turn off the buzzer. There are probably 10 or 20 magic combinations to set all types of things on cars...nothing on the Smartcraft gauges....

Glen E
05-10-2012, 12:57 PM
well, not exactly. Ive been doing fine with my setup the way it is. The only thing I never wanted to do was drain the gas out of two 100 gal tanks, just to calibate the gauge to be "more" correct.

When the OP posted, I only chimmed in to show there was someone else interested in a solution to the gauge being inaccurate.

I had never thought about pulling the sending units out and trying to calibrate it that way. And Im still not sure it is worth the effort to do that for what it might result in. Too bad I didnt try it last year when I put in new sending units.

Truth be told, yep, I thought it would be kind of interesting if someone more knowledgeable replied with....."There is a magical trick that Mercury didn't tell owners about that helps calibrate your fuel gauge more accurately. All you have to do is push button A twice, then button B once, honk your horn and shift it into reverse". Have you ever had to reset something on a GM car?

But so far, no one has suggested such an "easy fix" to a minimal problem.

Im OK with what I have. Re-fill at 40%. Rarely travel over 60 miles. Doubt Im ever going to run out of gas. I was just curious as to suggestions from someone who might be in the know.


Magic tricks or " Easter eggs" exist in the electronics world yes, but fuel senders are mechanical and 50 years old in their execution. As long as that occurs, they're ain't no magic.....

thumperlove
05-10-2012, 02:26 PM
Exactly what guage do you have?

fshmn
05-10-2012, 02:52 PM
Exactly what guage do you have?

I don't know what the OP has, but my Smartcraft speedometer is the gauge that gives me fuel remaining for both port and starboard tanks.
It is the blue back gauge and the number on the back is:
Mercury No.: 79-889223 A03
VDO Nr.: N01 1?? 153

date: 0?/07

gauge label has been scratched off where I inserted "?"

Again, this is only a curiosity issue with me. I'm managing my fuel just fine. If there was a minimal "tweak" to correct the gauge, I'd do it. If not, I'd rather go fishing.

Now, if it were a continuous "seat buzzer" like SaltyG experienced in the car................. I'd cut a wire if I had to. :grin:

me00351
05-10-2012, 07:19 PM
Here's a picture of my dash

http://i52.tinypic.com/20rjtsn.jpg


I've got twin Smartcraft 1000 tachs and the fuel gauges are the smaller link gauges.
I agree with FSHMN that the fuel gauge is simply a backup since my fuel management system is very accurate. It shows amount of fuel used for each engine on the SC 1000, total fuel used on my SC 5000, and gallons remaining on my Garmin 7212.
I don't see myself emptying the tanks (117 gal each) in order to make the fuel gauges more accurate.
Thanks for the input as I was hoping for hoping for a way to fool the smartcraft .

thumperlove
05-11-2012, 04:43 AM
I just sent him the pic of your dash. I sent him your original post and he asked what guage. I will post his response

thumperlove
05-11-2012, 07:55 AM
Here is the response:

"Looking at the age of the boat I dont think so. They have a system view and SC1000 Guages that are probally 2006 or before. You could fake out the system if you have another sender. Then you would just move the float to the desired position and calibrate."

me00351
05-11-2012, 05:36 PM
Thanks Thumper for the idea of using another sender to fool the system.
The standard sender is 35-240 ohms so an evenly shaped tank should give a reading of 35ohms for full, 86.25 for 3/4, 137.5 for 1/2 , 188.75 for 1/4 and 240 for empty.

My tanks are an irregular shape so I'd have to use a process to account for the shape.
I could use the 240 ohms to simulate an empty tank and take a reading from my sending unit when the SC1000 shows the fuel used at each 1/4 tank(29.25 gal). That would give me a true ohms reading . I could apply those values by using the "fooler" sender .
Most of us boaters like to tinker and make our boats better whether it's compounding and waxing , new electronics & led lights or finding a way to make our gauges more accurate.
This is not that big of a deal but now I have a good idea how to experiment without emptying my gas tanks.

divefreak
05-11-2012, 10:10 PM
If you have 2 tanks of similar size put enough fuel in to get 1 full and use a transferpump....

tank 1 emptied into tank 2

calibrate tank 1 with the fuel from tank 2

than calibrate the now empty tank 2 with the fuel from tank 1....

top off tank 1 at the gas pump

and your are done.



Search Engine Friendly URLs by vBSEO 3.2.0