Inboard tank gauge accuracy

[amateurfishing]

i have an '84 crestliner and to the best of my knowledge all boat parts are circa '84 as well. i have a 18 gal in floor tank (ive been told) & without empyting tank manually & such is there any way to test the accuracy of my tank guage? put 10 gallons in bout 2 1/2 months ago & have been on 2 trips since (1 was mille lacs). yesterday my guage showed almost a full tank all a.m and i am pretty sure this cant be possible. is this something that will need replacing? or any parts that can be checked in any way? & yes i am completely mechanically illiterate. or is this the norm with something of this age and time to update/upgrade sensors, wiring, & guage?

[fishnowworknever]

Do you have access to the tank? Typically there will be 2 wires running to your tank from the gauges, in addition to those there is probably one that goes back towards the transom and one coming from the filler (ground wires)

Where those 2 wires from the gauges connect is usually where the sensor is going to be located. I'd say it's probably stuck on Full.

When you turn the key off does it go to Empty or stay on full? If it stays on full maybe the gauge is bad...if it goes to empty then back to full when the key is on it could be either the sensor or gauge. Either way if you have access to then tank it should not be too hard to replace the sensor in the tank.

[amateurfishing]

yes, i have in floor access to the electrical

there is a pull button knob connected to the guage, the guage is always off (even when motor is running) unless this knob is pulled out. i have no idea why the guage is connected to the knob, thats the way it came, so i always pull the knob out to check the fuel guage but sadly still do not trust it cause 90% of time it says full

[delcecchi]

My Lund has a 32 gallon tank. When the gauge comes off the peg, that means I am at 2/3 or maybe a little less. When the needle stays off the peg, I put gas in because that is a little less than 1/2 tank.

[amateurfishing]

My Lund has a 32 gallon tank. When the gauge comes off the peg, that means I am at 2/3 or maybe a little less. When the needle stays off the peg, I put gas in because that is a little less than 1/2 tank.

so your gas guage does not work in the same way as an automobile gas guage?

[amateurfishing]

i did some online research and apparently crestliner has a somewhat bad record with floats sticking/bad sender.....anyone know of how to check these?

[SkunkedAgain]

There quite possibly could be a problem with your gauge. However, considering your statement I feel compelled to make sure that your boat was parked flat as to give an accurate reading.

[amateurfishing]

parked flat on water when dead calm.....mmmm i take that bad, usually watching guage when on the move from one spot to next, are they not supposed to be accurate when moving?

[delcecchi]

Well, my Ford goes like 50 miles before the needle goes off the peg, so the boat works sort of like my car.

I thing the big thing is that the tank is at different angles depending on hwo the boat is sitting in the water. Gauge would probably be just fine if boat was sitting flat. Sitting rear down like it does seems to change things.

If you are really worried, set up the trip odometer on your gps and monitor the miles since last fill up.

[amateurfishing]

Well, my Ford goes like 50 miles before the needle goes off the peg, so the boat works sort of like my car.

I thing the big thing is that the tank is at different angles depending on hwo the boat is sitting in the water. Gauge would probably be just fine if boat was sitting flat. Sitting rear down like it does seems to change things.

If you are really worried, set up the trip odometer on your gps and monitor the miles since last fill up.

good idea....but to clarify so no boat tank guage is accurate unless sitting level on a trailer?

[delcecchi]

I don't know about all boats or even many boats. I know about my boat is all I know. But if you think about it, the gauge is a float in the gas tank which typically is a box shaped thing, probably not too tall, maybe a foot? Think of it being 3/4 full. If it is laying flat the float will be at one height. Now jack up one end by 6 inches or so. all the empty space will go to the uphill end and the float in the middle will think the tank is full.

that's the way I picture it working anyway. I would have to take half the boat apart to see how it really works. Get 4 5 gallon cans of gas. Go fishing until you run out of gas. Pour in a can, look at gauge. Pour in next can, look at gauge. repeat with third and fourth can.

Or you can do like I did. Run it down to half or 3/4 and look at how much gas it takes to fill it up. After a few times you will have an idea of what half a tank looks like etc. (while learning I ran out of gas a time or two, fortunately the boat has a motorcycle style reserve valve and I have a kicker as backup. )

Here is my latest idea.

[Capt. H (Ret.)]

IMO gas guages on boats have always been wonder guage where you look at them and wonder how much fuel you have. I always check mine on plane. I watch the guage and then watch how many gallons I put in it to fill it up. That gives me a pretty good indication of how much gas is left. I would rather buy gas than run out.

Mike

[fishingstar]

my boat's gas gauge was very inconsistent. Most electrical problems come for bad ground. most boats have a grounding strip I have a lund and they put their's is on the inside of the transom. I ran a bonding cable from the batteries ground to the grounding strip. problem fixed

Dan

[amateurfishing]

boat sat in garage for 3 weeks gearing up for the 29th. have it level and guage has been showing me almost empty. started adding gas yesterday from a 5 gal can & 3 gallons into it gas is to tip top of gas cap. none of this makes sense, especially since im pretty sure boat is level....does that not necessarily mean gas tank is level or accurate?

[fishingstar]

look in to my previous post

[amateurfishing]

just took cover off tank for first time....wiring looks, moldy, gunky, & nasty. wires/terminals probably need a good cleaning, if i attempt to clean them, do i need to disconnect from battery or can i leave connected?

[TSchultz]

I have been in many many boats, not one had a gas gauge that I felt was "reliable" at least not in the sense of what you will find in your truck or car. This includes top of the line rangers, though they seem to be the best of the lot, they are still not like you're truck. I don't think the floats or anything else is of high enough qaulity to deal with the constant pounding that you find in a boat. Floats stick in some situations other situations they read true. Seems it just depends and the best you can do is try to find some constant for your specific boat where at least is reads consistantly and go off of that. Now consistently may not be accurate, but you can gauge what you have for gas in it at that point.