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I am running 454s with the Sierra 18-7945 fuel filters. If I have water in my tank would I expect to see water when I pull a filter and dump its contents or is the water trapped somewhere in the filter?

Peter

Water would dump out with the gas. Let it sit a bit and it will separate pretty quickly.

I always dump my filters into a clean container. If the fuel looks good, no water, not a lot of sediment I filter it back into the tank. You can do that a couple of ways, you can get a an auto fuel filter and put it inline in a fuel rated hose, and use a funnel and poor the gas back through. Takes a while but gravity will do the job.

The other way is to line a funnel with coffee filters and poor it thru the coffee filter.

You can check for it quickly, if you pull the access plate and probe the tank with a stick and some water paste.

If you're unfamiliar with water paste, it's a chemical that changes color in the presence of water (but not petroleum products). You just put some on a stick and 'stick' the tank.

https://www.tractorsupply.com/tsc/produ ... ding-paste

I'll 2nd what Tony said about dumping contents into a glass jug, let it settle and see what is coming out.

I use it as a way to see what is happening with tank and who I am buying fuel from.
Yes, water would come out, it is not trapped.

Usually a bit of sediment is normal, alot sends up red flags.
It used to be normal to find a few droplets of water in the fuel. Looked like a drop of mercury sitting at the bottom in a little ball. More sent up Red Flags.

For today...if your running ethanol fuel you should not be seeing water in that filter as the ethanol is like the old dry gas, that is it soaks up water, mingles with fuel and can be burnt along with the fuel.

The ethanol soaks up only so much water before it becomes saturated at which time it is said to come out of phase...ethanol and water drop to the bottom of the tank.
Bad for two reasons-
Ethanol provides much of your octane.
Alcohol levels approaching 15% or so etch and eat Alum...not good in an alum tank.

Not saying to scare or whatever...just saying be concerned and don't let it go.


Getting a load of bad water laden fuel...not sure what happens, or if water has time to get absorbed.


Also playing around with fuel and open fuel tanks...please be extremely careful. Those fumes drop low...when around them for long periods your nose stops smelling them. Just be careful.

Thanks for all of the suggestions. I found some water finder paste at a local auto parts store and plan to check the tank this weekend. The cap which appears to give access on the top of the tank is about 3" in diameter and held on by six screws. Based on some online research I got some Permatex Aviation Form-a-Gasket to reseal the cap and screw holes when I replace the cap. Other than that I plan to use the same precautions that I use when refueling (close all doors and windows while working; ventilate the boat thoroughly when finished.)

Are there any other precautions that I should take?

If I do find water in the bottom of the tank, how do I remove it?

The process of checking for water may become cumbersome if each and every time you fill-up, you have to unscrew 6 bolts, check for the right positioning of the gasket etc.

What I’ve once seen on a diesel boat (only for diesel applications) is that the guy had made a small hole in the tank’s top surface and had welded through a very small diameter tube (of a total length of approx. 5 cm), of which half was inside the tank and the other half was sticking out on top of the tank. This tube was normally sealed off with some trimmed cork from a wine bottle. Each time he wanted to check for water in the tank, he would remove the cork and stick through the tube his spear gun’s rod the tip of which was covered in this cream, all the way to the bottom.

If you are not as adventurous, you can do the same with a proper tube that seals off with a threaded cap. Perhaps then you could apply this method on a gas tank too, but before any drilling and welding, make sure your tank is empty and gas free.
The hole has to be towards the aft top side of the tank, where the heavier water accumulates when the boat accelerates.

Peter,

Make sdurdd tgge tank is mot filled right to the top so you have some room for expansion on a hot day. You dongg need it splashing out on you.

What makes you think you have water in the tank?

You can use the form a gasket or you can buy gasket material and make your own.

Last time I was out, my starboard engine cut out after running a few minutes at about 2500 rpm. Something was making a noise which I can only describe as a sort of metalic flapping noise. At that point it started loosing power. When I described the symptoms to the guy who runs my marina (a certified Mercruiser mechanic) he suggested preignition caused by water in the fuel. His theory was that when I got up on a plane the water sloshed to the aft end of the tank and got picked up by the starboard engine's fuel line.

Whatever the case, by the time Sea Tow arrived three hours later I was able to restart and come back at idle speed. Oil pressure and temperature were in their normal ranges before and after I had the problem. Both engines had been running normally two weeks earlier when I made the 20 minute run from the yard in Sayville to Oakdale. I replaced the electronic ignition module late last summer so I did not expect that it was the problem. Also, when I had the electronic ignition problem last summer it was not making that noise. It was just starting to miss when I started to open it up.

I dumped out the contents of the fuel filter and saw no water or debris although I did not let it settle to make certain. I have a new fuel filter (10 micron Sierra) in there now and also replace the coil

I checked the compression on the starboard engine and all cylinders were in the 130-140 range.

After looking at the boat this afternoon I am thinking that the noises I was hearing were coming from the loose parts of the cabinet work. After I brought my boat over from the yard I started work on removing the counter top and cabinet so that I could replace the rotten section of the sole underneath. I have not moved them yet but they are no longer secured to the bulkheads.

I hope to find time to test this theory later this week.

Peter

Are your engines fuel injected our carbs?

Our old 454s would run great until we stopped to fi sh. Crank them up 30 minutes later, the starboard rngine would duue whern you accelerated. We eventuallu just wired the vhojes ooen and that ended that problem. Never had a problem starting thrrm with the choke wired open.

Peter

Are your engines fuel injected our carbs?

Our old 454s would run great until we stopped to fi sh. Crank them up 30 minutes later, the starboard rngine would duue whern you accelerated. We eventuallu just wired the vhojes ooen and that ended that problem. Never had a problem starting thrrm with the choke wired open.

Given that therrdd is a single pick up feeding both engines, if you h ad water, both engines would quit on you.

Tony,

Mine are carbureted. It looks like I have separate pick ups for port and starboard.

I will check the automatic choke.

On my Carter carbs I used to wind up with water in the fuel bowls. Only a drop or so...but when running or trying to run I'd get that sputtering, couldn't get going, knocking pinging stuff.

There's a bunch of tricks that sometimes kinda work. But what always worked was opening up and cleaning carb.

Took me awhile, but I found out water would make it way onto flame arrestor, follow the holddown screw and make its way into the bowl. I tested it by placing a pie tin upside down over the arrestor and never had issue again. Looked stupid...but worked.

Anyway, just saying sometime water/dirt find their way in.

Peter

I still think if you had water both engines would have an issue since you would be drawing from one tank.

Perhaps one pick up is higher than the other.

Right now, I'm thinking it's and ignition problem (either the coil or the electronic ignition kit) since I was able restart the engine after it had cooled down for a couple of hours while I was waiting for Sea Tow. I know from my experience with cars that this is typical of these components fail when they are hot and work again when they cool down.

The electronic ignition kit in my starboard engine is one of those units which fits inside of the distributor (Sierra part # 18-5296-2). I replaced that last summer to fix a similar problem. Put in a new coil a couple of days ago but I have not had time to test it under way.

Peter

I member a mod use on the mid 70s carbs that weoulkd get into and shut everything down. I used to carry a spare in the car.

The PO of my boat said the distributors were getting damp and causing the engines to shut down. Actually, the coils were the culprit, they would get hot as the engine ran and the start to break down. I finally replaced them, and the problem went away. I have since had to replace the port coil twice. Don't think they are made well anymore.