95 SN Fuel Sending Unit problems

I recently replaced the float/sending unit because my fuel gauge always drifted to full upon turning the key. I found this out the hard way on my 1st trip out after purchasing last summer. Removed the old and matched/trimmed new to same length and re-installed. There were 2 wires attached; a red wire to the center post and a green wire attached to the tab (ground) and it was also spliced to another green attached to a bolt on top of the gas tank unit. Fuel gauge does the same thing with the key turned on and if I removed the green wire it slowly drops to empty. The tank is approx half full just from looking at it.

I guess I need to check continuity of the wires and make sure I have 12vdc coming from the green and red wires. Other than that, I am assuming the gauge is good based on its delflections.

Any suggestions?

This works on boats up to 93, that I know. Pretty sure it holds true for 95:

Quick check -

With power off, pull a wire off the sender. Good gauge should NOT move.
With power on, pull a wire off the sender. Good gauge should drop from the level it was reading to 0.
With power on, touch one wire to other wire. Good gauge should peg full and stay pegged at full.

If all that shows a good gauge, make sure you have the correct sender (Probably don't).... you want an SSS/SSL Standard American 240-33 ohms sender.... NOT a European standard (0-180 ohms) which is what many later boats use.

As everyone here knows, I like the WEMA fuel senders. Check out the thread I started and Art took the wind out of...... check out www.wemausa.com

Steve

Kris, Steve, Peter:
Thank you all for the information you have provided. The boat is at my in-laws, covered in a barn so I can't get to it during the week right now.

So as not to put anybody on report, I am asking for recommendations on where to get a replacement sending unit vice telling you where I bought my current one.

The replacement unit came with no paperwork, no tech specs or instructions. Since I ran out of gas on my first endeavor in the middle of a river, I assumed it was the sending unit. The gage would deflect from empty to full after turning the ignition switch. I thought this would be a quick fix.

So, here are some answers to your questions:
Without tracing all the wires and NOT having a wiring diagram for a 95, I will have to figure out the lighting circuit and see if it's crossed.

My next course of action is do all the things you guys have mentioned. I am going to check continuity on the wires from the gage to the sending unit, as well. I did not think to check the resistance band of the new unit, but I will.
I will have to look at the sending unit to find out what type, brand and the specs are for it. I willing to bet I will not find the answers to that by looking at it.

Steve, I checked out the WEMA page, how far do I measure down for the length of the float arm? 2-4 inches from the bottom??

BTW - the need for a wiring diagram is probably moot. The gauge is your multi-meter. If it does anything that I didn't specify in the troubleshooting, you have a wiring issue.....then go mucking with dash wiring (yuk!).

If it behaves in the ways listed, get the right sender.....

BTW - the need for a wiring diagram is probably moot. The gauge is your multi-meter. If it does anything that I didn't specify in the troubleshooting, you have a wiring issue.....then go mucking with dash wiring (yuk!).

If it behaves in the ways listed, get the right sender.....

After checking to make sure you dont have a gauge/sender mismatch, I'd clean the connections and test for continuity from front to back. If that checks out, I'd probably disconnect the wires entirely and run a few test ones to see if behavior returns to normal. If it does, you know youve got an issue in the wiring somewhere.

Hold off on buying a new gauge...
Does your wiring setup look roughly like this?:
http://www.correctcraftfan.com/forum/uploads/6518/Sender.JPG

That pink wire is the sender wire. The black is/should be ground to either the engine block or the dash ground or the battery. The shortest and best route would be just the engine block if you're adding new.

I believe the green is the ground for the stern light. It may also ground the fuel filler neck.

A fuel gauge works the same as the temp gauge and oil pressure gauge. The gauge itself is essentially an Ohm-meter and the sender just provides variable resistance to ground, the engine block. The gauge reads that change in resistance.

Of course, in the case of the fuel gauge, the engine block isn't nearby, so that metal ring is essentially "the engine block", the thing is, that ring needs to be grounded to the block. So, if that black wire is sketchy or loose, your not going to get a good ground.

If you're blue lighting wire is hitting anything in the vicinity, that's going to screw up your whole deal! That's essentially carrying un-metered positive intended for your stern light.

Before you chuck money at a fuel gauge, at least post a pic of how you have your sender wired. Also, run an additional ground from the metal ring/tab direct to your block, and see if that helps things.

There should not be any voltage on the pink,that would very dangerous having that going right into the tank. The gauge will have 12v but the pink will just have the resistance to ground on it. If that's what is going on there is your problem,but if your confusing your terminology all bets are off.

It looks like a new thread was started with the final outcome:
It was the Guage