Gage problems

Tib99

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Sep 2, 2017
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Hi, ive got a 2007 maxum mx1800. Oil pressure gage is not working, fuel gage indicates always full and temperature gage even engine cold indicates 100. Ive tested wiring for oil pressure sender, its good and sender its self has the right resistance with engine off and running. So i guess its the gage.

Fuel i tested the wiring, seems good. I removed fuel sender from tank, resistance is good when moving fliat from top to bottom. Gage pegs full but never moves from there...

Is it possible 3 gages are faulty?? Grounds are good with 0.5 ohms, and voltage is battery voltage 12.6v. Kinda annoying. Even. Ench tested gage with powerpack. Why they all letting go at once?
 

Silvertip

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Sep 22, 2003
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28,771
Unless there was an extreme power surge in your electrical system it is highly unlikely all three gauges are bad. In fact I doubt any of them are. If you look at the TEMP gauge, you might see the lowest number is 100 degrees. How can it read lower because there is peg for the needle at that point. Calibration of the float arm for the fuel sender is essential for an accurate reading. It is a "float" so the amount of fuel in the tank, orientation of the boat (on plane, at rest, on a trailer) all affect the reading. With the boat in the water, calibrate the arm so the gauge reads empty with the tank NEARLY empty. Why empty? Because you cannot calibrate the arm for accurate full, 1/2 or empty readings. One of the three but not all three. You want to know when you need fuel. You filled the tank so you know what full is. Only the gauge (or a stalled engine) can tell you if you are out of fuel so calibrate the arm for an accurate empty reading. Gauges that peg full usually have the "S" terminal grounded by a bad connection.
 

alldodge

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Mar 8, 2009
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43,241
Being a Maxum let me ask are these individual and separate gauges, or a multi gauge in one?
 

Tib99

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Joined
Sep 2, 2017
Messages
4
Unless there was an extreme power surge in your electrical system it is highly unlikely all three gauges are bad. In fact I doubt any of them are. If you look at the TEMP gauge, you might see the lowest number is 100 degrees. How can it read lower because there is peg for the needle at that point. Calibration of the float arm for the fuel sender is essential for an accurate reading. It is a "float" so the amount of fuel in the tank, orientation of the boat (on plane, at rest, on a trailer) all affect the reading. With the boat in the water, calibrate the arm so the gauge reads empty with the tank NEARLY empty. Why empty? Because you cannot calibrate the arm for accurate full, 1/2 or empty readings. One of the three but not all three. You want to know when you need fuel. You filled the tank so you know what full is. Only the gauge (or a stalled engine) can tell you if you are out of fuel so calibrate the arm for an accurate empty reading. Gauges that peg full usually have the "S" terminal grounded by a bad connection.

My float works fine and gas gage always indicates pass full, resistance was checked for float in all positions. Oil pressure gage never moves, sensor resistance is within spec at zero pressure and running changes. Temperature gage needle is above lowest peg even gage unplugged...
 

alldodge

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Mar 8, 2009
Messages
43,241
Recheck the wiring to the gauges and make sure the wires are on the post they should be. In other words just because the 12V wire was on that post doesn't mean it should have been.

If all the checks out and gauges work as they should (fuel and Oil peg full and high when since lead is grounded) and you know the wiring is correct, only thing left is the senders
 

Tib99

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Sep 2, 2017
Messages
4
I removed oil pressure gage and bench tested it with powerpack, needle does not move when sender wire (pin) is grounded. 12 v to ignition pin and ground on ground pin.
 
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