Fuel Gauge

[gero1]

put in new sender, wires all look good, when moter is running, the needle bounces around and when i rev moter the needle goes right to e even when tank is full. bought new multi meter today but dont know where to start

[txtaz]

Hey Gero1,
I would start with a set of jumpers. Put a jumper wire on the batt + and to the meter + and try again, then try the neg. If not resolved it is in the signal wire or tank ground. This way you isolate the wiring harness.
I would guess you have some dirty terminals on the leads to your meters. What I can't put together tho is how reving up drops voltage to the meter hence reading empty. It should be the opposite.
I know others will jump in here with more specific knowledge.
Good Luck.
Wes

[gero1]

do i disconnect the wires on the gauge or leave them on when i run the jumpers??

[txtaz]

Gero1,
I would disconnect them just to be safe. Also, depending on the problem, it's always better to isolate to be sure.
Wes

[gero1]

went to town to get some wire, undid ground on gauge, went from battery to gauge, started boat, gauge still very wrong, heard strang noise, kinda like a rubber band being shot by your ear but came from moter area, now no water going through moter(s.o.b) i wonder which water pump went out??

[RedDog]

Bet you damaged your seawater pump while running it on the muffs. I had mine go bad while out on the water at the first of the season - convinced my earlier in the day run on the muffs contributed to an early failure.

Regarding your fuel gauge issue, the only way I know how much fuel I have is when I fill it up and overflow the inlet nozzle :frown:

[txtaz]

I agree with RedDog, that really is the only way to know. I have yet to see a fuel gauge that read accurate on a boat. I'm sure there are some, just I haven't seen one. On mine, when the needle starts bouncing off of full, I have 8 gallons left in a 50 gallon tank. Over the winter I'm going to figure out how to make it more accurate. An inline resistor on the signal wire should do it, but I still don't expect it to be linear, just a little more accurate.
I would expect also, you spun your seawater pump. Not to hard to replace on my 18. Poodle can get the parts for ya.
When you get the pump replaced, try the positive jumper, then a signal jumper. It has to be one of those.
Good luck,
Wes
RedDog, why do you think running on muffs is bad for seawater pumps?