How to check fuel tank

[dmksails]

My diesel tank was about half-full as the boat sat over the winter. I need some suggestions for how to check the condition of the fuel and how to clean it up.

Or should I just drain the tank and start over?

[Sailmonkey]

Was the fuel good prior to winter?

Diesel doesn’t go bad like gasoline. I’d just use it up as is.

[dmksails]

Fuel seemed to be good. I'm concerned about condensation adding water to the tank over the winter. Water would settle to the bottom of the tank. I have a large maintenance port on the tank that I can open. How would I recognize water in the fuel?

[Dsanduril]

If you have a large port and can reach the bottom of the tank then use a dipstick with "water finding paste" or "fuel dipping paste". The brand I'm familiar with is Kolor Kut, but it will depend on location. Smear a little paste on the end of the stick, dip to the bottom of the tank. The paste changes color in water, when you pull it back up you can see how deep the water layer is by observing the color change.

If you don't want to buy paste for one shot see if your local gas/petrol station will give you a dollop.

[rbk]

You can always pick up hand pump, siphon or elec fuel pump and attach a length of clear hose or empty into a clear container and suck the sump on your tank (if equipped) or low spot, you should be able to see the water or any particulate. Keep sucking bottom until it’s clear. Put the fuel into a jerry and let settle. Put settled fuel back in tank and dispose of the rest accordingly. Or pay someone to polish it.

[NYSail]

Use a pump and vacuum bottom of tank to clean debris and any water. Also equip your boat with a quality filter / water separator and you will be fine. I vacuumed the bottom last season and got a plug of nasty stuff out..... I am not so conserved about water in fuel. I try to store boat over winter with an empty tank so in spring I have nice fresh fuel.

Greg

[Pete7]

If you haven't seen inside the tank for a while then as Greg says worth opening up the tank and having a look whilst filtering the fuel.

I made this little filter up for doing our tank. Fuel pump is a Faucet electric one off ebay and a standard CAV filter unit is good enough.

Hopefully the tank is reasonably clean but if you find something like this then a least you are not going to have to deal with it at sea, solo

Pete

[NYSail]

Wow.... wish I had a good access port. I only have the sender opening. I used a high volume pump and only found crud when I hit the sump...

[captmikem]

If you have a Racor, and you should. just run the engine for a while monitoring the bowl. you will see any water/bug collect in it. if it starts to fill use a water bottle (which everyone has plenty of) and drain the bad stuff into it.
Helps to motor around a bit to wash stuff back and forth.

Once it stays clear it is a good practice to change the filter and you are good to go.

M

[chiropaul]

Once you're done checking for water, you can add a cetane booster to refresh the fuel. Any auto supply store carries this.

[Cheechako]

Pump from the bottom of the tank with clear plastic tubing taped or wired to a dowel to ensure you are getting it off the bottom.. Put it in a glass jar. Let it settle a few hours. Electric fuel pumps are about $20 at NAPA I think. But you should be fine if it was fine last year. I rarely worried about how full the tank was thru winter in the PNW.

[HopCar]

Originally Posted by Dsanduril

If you have a large port and can reach the bottom of the tank then use a dipstick with "water finding paste" or "fuel dipping paste". The brand I'm familiar with is Kolor Kut, but it will depend on location. Smear a little paste on the end of the stick, dip to the bottom of the tank. The paste changes color in water, when you pull it back up you can see how deep the water layer is by observing the color change.

If you don't want to buy paste for one shot see if your local gas/petrol station will give you a dollop.

Do this first. You can get a stick down through the opening for the sender. If there isn’t enough clearance above the tank, you can do it with a weighted string.
https://www.amazon.com/Kolor-Kut-Oun...+finding+paste

[Billnpr]

We just did a sail from Tarpon Springs to Key West. The motor stopped after running about 6 hours. We found out that Diesel grows bacteria even after having the fuel polished a year ago. In the marina at Key West, we had the fuel polished again. It seems the the bacteria as it grows will coagulate like snot which will clog the intake pick-up tube in the fuel tank even before it gets to the filters. The filters the professional used looked like a swimming pool filter with a fine membrane around it. The pump was high volume so that the return hose was used to rinse the inside of the tank.

I would recommend investing in the external pump and filter. Remove the the pick-up and sending unit and filter the fuel several times.

[Pete7]

Originally Posted by chiropaul

Once you're done checking for water, you can add a cetane booster to refresh the fuel. Any auto supply store carries this.

Will this do any measurable good when added to diesel? Modern petrols perhaps, but diesel?

Pete

[Sailmonkey]

Originally Posted by Pete7

Will this do any measurable good when added to diesel? Modern petrols perhaps, but diesel?

Pete

Cetane booster is specifically for diesel, as Octane booster is for gasoline.