Water in Gas

[fishdan]

I have a 1984 115 hp inline 6 . I think it has some water in 18 gal built in gas tank . I have never treated it for water . What can I use to treat it with that is safe for motor and lines. THANKS DAN.

 

[dingbat]

Re: Water in Gas

If you have a 10 um filter installed that will take care of the water. If you don't have a 10 um filter I suggust you install one. A filter is cheap insurance considering the alternative

 

[fishdan]

Re: Water in Gas

where can i get one of these filters

 

[Woodnaut]

Re: Water in Gas

The inline fuel filter that DB suggests is the way to go. Also, the 10 micron is a good size and is what I use.

If the filter assembly has a clear bowl then you can easily monitor the situation to see if you have any water present. If it is the more economical spin-on cartridge type (like mine), you can still monitor the situation but it takes a little more work. After it's been in service for a couple of hours, CAREFULLY unscrew the cartridge and pour the entire contents into a LARGE, CLEAN glass jar. You can visibly inspect the gas to see if you have any discolored gas or free water. If the gas is clear and clean, then it goes back into the tank. If the gas is milky looking or contains free water on the bottom, then there is water in the tank. Check the O-ring on the cap to your deck filling port. Also, take a look at the placement of the fuel tank vent. The vent on my boat was originally in a location that was constantly getting splashed.

If your area happens to be making the switch from conventional gas to 10% ethanol, you might see some yuk in the fuel for a while. If you have any free water in the bottom of your tank it will start to combine with the ethanol. This will continue until there is no water left. (If this was the case, I would remove the tank level sending unit and maneuver a piece of rigid tubing into the lowest reaches of the tank and pull out the water. I've done this before with good results.) Also, you might need to check all of your fuel hoses to make sure they are ethanol resistant.

It's really a good idea to to use some type of fuel stabilizer. There will probably be lots of follow-up posts on this subject. (Stabil, Seafoam, etc.) I've been using some stuff called Star Tron with good results.

 

[jeff_smith_0423]

Re: Water in Gas

i've successfully used Iso-heet in the red bottle to treat wet gas. I left my fuel tank open, come off a WOT run and had my transom swamped. Probably took half a gallon of water straight into the tank. Engine ran crappily for the rest of the afternoon. Treated the remaining fuel with ISO heat and it burned fine for the rest of the tank.

 

[d.boat]

Re: Water in Gas

where can i get one of these filters

He's being kind of cryptic. What you're looking for is called a water separating filter. I've never heard them referred to as "a 10 um filter", but I've only been around water separating filters for 25 years. Racor is a common brand, but there are also OEM (i.e. Merc, BRP) systems. All of mine have been Racor on a multitude of different engines.

They are a canister type filtering system (mounting bracket and filter unit) intended to separate water from the fuel. They are generally mounted between the tank and the priming bulb. The canister looks a lot like an oil filter, but is not. Some systems are canister only and you just change regularly. Some have a drain bowl at the bottom that you drain regularly, and change the filter maybe once a year.

As someone else posted, I think the kind with the drain bowl at the bottom are best. Any marine supply store sells them, and I believe they are an essential piece of equipment for all outboards, and should be installed in every rigging, IMHO.

When you select your filter, just make sure the flow rate specification is more than adequate for your engine, sucking fuel at WOT.

A lot of people use water absorbing (or whatever they do) products such as Heet. I feel much more comfortable with the water sep. filter and have never used heet.

 

[Chris1956]

Re: Water in Gas

Dan, The first thing to do is to siphon out as much of the water as you can. Tilt up the tank (or trailer tongue) so the water will collect at the bottom rear of the tank. Now use a hand pump or siphon hose to transfer a gallon or so of the fuel into a clear container like a windshield washer bottle. The water will settle to the bottom and the gasoline may be poured back into the tank. Add a bit of 2 cycle oil, if you cannot see the water in the tank.

Now install the water seperator filter is you want.

 

[d.boat]

Re: Water in Gas

Dan, The first thing to do is to siphon out as much of the water as you can. Tilt up the tank (or trailer tongue) so the water will collect at the bottom rear of the tank. Now use a hand pump or siphon hose to transfer a gallon or so of the fuel into a clear container like a windshield washer bottle. The water will settle to the bottom and the gasoline may be poured back into the tank. Add a bit of 2 cycle oil, if you cannot see the water in the tank.

Now install the water seperator filter is you want.

Excellent advice. I recently drained my built in tanks. I have a portable tank for my kicker with a long (~6-8 feet?) hose and the conventional primer bulb. I removed the hose from that tank, and the engine fitting from the other end. I found it to be a very effective siphoning hose - I put the end in the built in tank, ran it over the side to gas cans on the ground, and once I got it primed, it siphoned very quickly. Just an idea.

Also, if you find it difficlut to get the water out of the tank, another way to deal with it is to let the water separating filter do it's job, but just drain it frequently... like every hour or so. I've dealt with quite a bit of water that way too. My normal routine is to check it every several hours of operation, but if I think there's more water in there (long lay-up w/ condensation), I'll just routinely drain it very frequently into a little jar and carefully pour the gas back in the tank (water sinks to the bottom of the jar).