YAMAHA FUEL GUAGE

[ORCA]

More help needed trouble shooting a faulty fuel guage or sending unit.

Can anyone tell me why a Yamaha instrument fuel guage reads at it's lowest level and flashing, when the tank is full?

Thanks in advance for your help.

IN GOD WE TRUST

ORCA

 

[enfish]

Most likely a stuck float on the sending unit. Could also be a bad ground wire.

http://www.greatgrady.com/forum/viewtopic.php?t=10772&highlight=

 

[catch22]

Agree with OnoEric... could very well be a stuck or bad sending unit, but check all the connections.

Here's a link for your 97 owners manual, (click on Spirit) - http://www.gradywhite.com/customer/manu ... ected=1997

The sending unit has a single pink wire on it that feeds up to the fuel gauge.

The fuel tank itself also has to be grounded for the gauge and sender to work. The tank has a metal tab, near the sending unit for grounding. The tab may have 2 ground wires on it. One comes from the fuel fill, the other goes to ground. The sending unit and ground tab are located at the back of the fuel tank, (see pg 2-3 in your manual). I'm not sure if the tank ground goes directly to the battery negative on your boat, or to a grounding bar, but check that out. If it does go directly to a battery ground, maybe that wire was over-looked when you replaced or removed a battery.

There's another view of the fuel tank on page 6-10.

 

[seasick]

Most if not all American senders read about 230 ohms at lowest level and about 30 ohms at highest level. Therefore, grounding the sender input lead at the gauge should result in a FULL reading. Disconnecting the sender lead should result in an EMPTY reading. So to test the guage, make sure it has 12 volts to its supply terminal and then ground the sender terminal. Gauge should read full. Undo the sender ground and gauge should read empty. If that works, you need to test at the sender connections.

 

[freddy063]

 

[ORCA]

WOW! Great Info. thank to all for you great help.

IN GOD WE TRUST

ORCA

 

[freddy063]

Orca make sure to responed back on what you found to fix the trouble, that way your learning could helps someone eles.

 

[ORCA]

HI FREDDY062

I will be glad to share anything I learn from using all the excellent help I received from the forum. Your reply was especially impressive as I have not seen a decision tree used that way before. Great Idea.

It will be a few days before I can post anything learned by using forum information, as it is 20 degrees F outdoors and that is where I have to work.

Thanks again Freddy 0 8)

ORCA

 

[freddy063]

it was just passing on what some else passed to me, thats how we all learn.

 

[JUST-IN-TIME]

the ohms things is garbage today, because so many different meters will read way way different

sounds like bad sender to me, because you have power to the gauge and these yami fuel gauges i have not seen fail yet

 

[fishhrd]

That happed to my 2007 222. I replaced the sending unit and everything worked properly. A grady dealer had mine in stock, can't remember the price but wasn't to bad. Easy install to do yourself also.

 

[freddy063]

maybe a bunch of crap, but the ohms show if theres a change, and if the tank or ground it bad, gauge etc, etc a good tool for the ones that don't know everything, like me.

 

[catch22]

maybe a bunch of crap, but the ohms show if theres a change, and if the tank or ground it bad, gauge etc, etc a good tool for the ones that don't know everything, like me.

Agree 100%. :wink:

That's what the fuel gauge is!!!... an ohm/volt meter... and the sending unit is a variable resister. Basically, the fuel gauge, (meter) shows the position of the float on the sending unit.

How else would you check it, if not with an ohm meter? :roll:

Here's a pretty good example of a basic diagram.

Your sending unit may be physically different, (round tube w/self contained float) but works the same way. Same thing goes for the gauge... yours may use a bar graph, instead of the "needle" type.

 

[JUST-IN-TIME]

you guys just do it too hard these days, LOL

take the pink wire off sender

ground it to tank

turn key on

if gauge reads full = bad sender

if gauge reads empty = bad ground, bad wire's



Problems with using OHM's

Every meter reads different
Weather plays a key roll

But use if you want, i just use the alarm on meter to check short 2 grounds and continuity

 

[catch22]

if gauge reads empty = bad ground, bad wire's

Or..... BAD GAUGE!

Again... your fuel gauge is an ohm meter. If it's bad.... guess what you're gona need... an OHM METER!

And how would you check "bad ground, bad wire's"?

Wait for it.... wait for it....

An OHM METER!

Problems with using OHM's

Every meter reads different
Weather plays a key roll

One more time.... your fuel gauge is an ohm meter.

As Freddy063 pointed out... your looking for "change" not accuracy.

Yea, there's always more than one way to "skin a cat". You can remove a screw with vice-grips, you can "chisel" off a broken bolt head with a screw driver and you can remove a brake drum with a sledge hammer... but.... if you'd like to follow that old saying, "Right tool, for the right job" a multi-meter is the right tool.

 

[JUST-IN-TIME]

if the gauge was bad, it would not turn on, period

I keep i simple, thats it

some of you guys just do twice as much work

 

[Obxsandbar]

Just wanted to say thanks, the information the group provided made this a quick and simple fix for a change. Thanks