Broken fuel gauge and can't use a dip stick. What now?

[goodiefun]

I just bought my first boat (1979 Bristol 29.9) which had a "new" fuel tank installed at some point in the last 20 years. Unfortunately, the tank was not installed inline with the opening in the deck (the hose has two almost 90 degree bends in it between the tank and the deck) and the fuel gauge is broken. Does anyone know what I can do to figure out how much fuel is in the tank? I can't use a wooden dowel, or any other type of rigid instrument, to measure the fuel due to the two bends in the hose. Any suggestions would be greatly appreciated. Thanks so much!

[rslifkin]

What's preventing you from fixing the fuel gauge?

[goodiefun]

The mechanic won't be able to replace the gauge until the boat is hauled out in the fall. I am looking for a temporary solution until then.

[marcjsmith]

is the tank visible from any other location on board so you could install a vented sight glass

or could you grab a flexible dipstick from some long forgotten van/truck in a junkyard the down side to that is calibration, and whether or not you could actually see the fuel on the dipstick


whats stopping the gauge from being replaced while the boat is in the water?


otherwise, fill the tank. log your engine hours. run the engine for 5 hours under normal load, then refill the tank. and calculate your engine burn rate

[Marathon1150]

Not sure if your interest is to monitor fuel levels or to determine total fuel capacity. I am assuming that it is not the latter, but if it is, ask the PO what the volume is if possible or measure the tank dimensions (the latter may not be a trivial exercise because of non-square angles in the build).

Fuel gauges are typically quite simple and those that I am familiar with can be removed from the tank for repair and also provide access to the tank. Buying a new gauge might be simpler than trying to fix a broken one if you have already looked at issues like continuity between the float sender and the gauge.

There add on gauge systems that are non-invasive. One of my boats has an Accugauge system that uses sensors on the outside of the tank. It is not super accurate but certainly provides indicative data regarding how much liquid remains in a tank.

In terms of monitoring fuel levels, using engine run time will work. You may need to use estimates of how much fuel the engine uses per hour from the manufacturer and web sources. And then derive data for your boat from run times and how much fuel is added each time you fill up - noting how many hours the engine ran to use that much fuel. IMHO this is the most accurate system.

Good luck with this one.

[donradcliffe]

Originally Posted by goodiefun

The mechanic won't be able to replace the gauge until the boat is hauled out in the fall. I am looking for a temporary solution until then.

Get another mechanic. That job can certainly be done in the water.

[Calif.Ted]

Fill it, then fill again after 10-20 hrs run time and you can do the math from there.

[SeaStory]

We fill to gurgle and then track engine hours. Our engine hours meter is also broken, so we track that in our log.

[goodiefun]

Thanks for the suggestions. The boat has been at a yard where they were supposed to make a bunch of repairs over the Spring (including replacing the fuel gauge). Long story short, the mechanic told me a few days ago that he hasn’t gotten to my boat, and that he doesn’t know when he will get to my boat, and that I should come back in the fall since my repairs aren’t critical. My launch is scheduled for tomorrow and I am trying to gauge how much fuel is in the tank before I leave the yard. Guess it won’t be possible to know before I head out. Thanks again!

[marcjsmith]

feel your pain goodie. I needed a 12" flexible fuel return line made up.

I took it off the boat and gave it to the shop at the marina to fabricate. two weeks later they hadn't even taken it out of the zip lock baggie I had it in. He said they'd get to to that week. I said "why would i expect the outcome after week 3 be any different than the previous 2 weeks" not sure he liked my honest frankness



I took the hose to a hydraulic hose place (which I should have done in the first place) and walked out with a new hose in 30 minutes.


do you have access to the sending unit on the tank. Ie could you take it off and then probe inside.



tap the side of the tank listen for change in sound...


tie a lead fish sinker onto the end of a string drop it down the fuel filler neck. hope that it get past the bends and into the tank. have someone inside listen for when the sinker strikes the bottom of the tank.


pull it back up and look at the string that has absorbed some of the fuel....and gauge your level that way.

[Cheechako]

Originally Posted by goodiefun

Thanks for the suggestions. The boat has been at a yard where they were supposed to make a bunch of repairs over the Spring (including replacing the fuel gauge). Long story short, the mechanic told me a few days ago that he hasn’t gotten to my boat, and that he doesn’t know when he will get to my boat, and that I should come back in the fall since my repairs aren’t critical. My launch is scheduled for tomorrow and I am trying to gauge how much fuel is in the tank before I leave the yard. Guess it won’t be possible to know before I head out. Thanks again!

You need to get to the top of the tank. Can you? I assume you are talking an electric fuel gauge? If so there is a sender on the top of the tank. Round with a wire to it and 6-8 screws. Electrical fuel gauges seem to be broken more than they work. The mechanical are reliable.

You can buy a mechanical sender that fits in that hole. It reads right on the top at the tank. NONE OF THESE Electrical or mechanical ARE VERY ACCURATE THOUGH! . You just have to get used to what yours means at what reading.
Keep a fuel and hours log, eventually you will know by hours used.

https://www.amazon.com/Moeller-03572...91135113&psc=1

[C420sailor]

Burn rates are surprisingly accurate.

[Danm1]

Plastic or metal tank? If plastic, and you can get an angle on it, try shining a high tight beam at it. The fuel level is pretty clear on mine.
Plan B, pour in a couple of gallons so you know you have that much. I tend to bring a Jerry can over to the boat from shore every few hours of run time cause it saves a few bucks and the hassle of finding a fuel dock.

[moseriw]

Install a new fuel gauge? Within 2 hrs if everything goes wrong.

[Sailorman40]

If you have a non-contact thermometer you can run the laser up and down the tank to determine the level of fuel Temperature changes at fuel level Have used this successfully in past