how do you drain and clean fuel tank?

Don S/V ILLusion · Sep 18, 2009

Mac
Good solid boat, we used to have one. The tank location limits removal to one of two ways - cut it and remove through the cockpit locker or remove the engine. The term "A4" denotes a gas engine but one of the universal diesels is also called an A4. The reason I mention this is because simply pumping a diesel tank is not sufficient to properly clean it - too much gunk will remain on the walls requiring mechanical cleaning. A gas tank is much easier to clean without opening it up.

There are no keel bolts - the keel is integral to the hull with lead shot glassed into it.

CalebD · Sep 18, 2009

While Don is correct that Universal made a diesel engine that they labeled 'Atomic' (equiv. to M35) I am quite certain the 'Atomic 4' or A4 is a gasoline engine.
I have an A4 on my boat and am considering doing the same job on my boat this fall or spring. The fuel fill on my boat is on the cockpit floor so I can envision getting a long enough hose or tubing that can be weighted so it sits on the bottom of the tank, while routing the other end over the side and down to the ground to a container (or 2). Getting a siphon started might entail using some fluid pump as long as it creates no sparks.
Once most of the gas was siphoned off then what?

Moyer Marine (A4 specialists) recommend putting Marvel Mystery Oil in the fuel tank, which we do, so there may be some of this very light weight (< 5 W) oil in your tank as well.

I am curious to hear what others who have 'cleaned' their gas tanks have to say about the procedure(s).

Rich Stidger · Sep 18, 2009

Mac, not so fast....

Before you pull it for a rebuild, why don't you see if it will run satisfactorily?

I would disconnect the existing tank and attach a small container of fresh gasoline. Provide a bucket of water for the engine to pull for cooling and give it a go.

Then siphon the tank of the old gasoline. I would try cleaning the tank in place using a garden sprayer with fresh gasoline in it and a custom bent tube that will let you spray fresh gasoline inside the tank. The new gasoline is pretty good at dissolving deposits, but you could also cut the new gas with a quart of carb cleaner. Siphon all that stuff out and I think you will have a pretty clean tank.

Don't forget to change all the rubber fuel lines to hoses that are compatible with today's ethanol gas mixtures- you may have the original fuel lines present.

Also, even if the engine seems to run well, you may want to do a carb rebuild to clean out any deposits in the carb itself.

I had a A4 in my last boat, and I did pull it for a rebuild because it ran poorly and had a bad history. It did run better after the rebuild, but I was still plaqued with running issues that I believe were due to a weak fuel pump. There are conversions available for electric fuel pumps and electronic ignition.

Of course the option to re-power with a diesel is always available- for a price.

Good luck.

CalebD · Sep 18, 2009

I am going to agree with Rich Stidger. You should first try to see if you can get that old flat head engine to turn over. If you have not visited the Moyer Marine forums you have not given your old engine a chance: http://www.moyermarine.com/forums/index.php
Your first steps would be to get new spark plugs, wires, points (if not electronic ignition), change the oil (SAE 30W oil - Rotella 'T' is great), new battery and spray in some MMO (Marvel Mystery Oil) into the cylinders from the plug holes - this can help lubricate the valves and pistons.
These old engines are so simple that they really only need three things to run: spark, clean fuel and air.
If it wont start after replacing the parts I've mentioned then the fuel pump, carb. and ignition coil need to be looked at. Beyond these failure points you can have a blocked exhaust system.
A little ether (starting fluid) sprayed on the air intake of the carb will tell you quickly if you have spark and a working starter motor when the engine turns over, even begrudgingly.
As Don suggested an alternate clean fuel supply is a good idea.
All kinds of things go wrong but I have learned to love this old engine I have (42 years old) as I get to know more about it and have never had to have a 'mechanic' work on it or pull it (knock on wood).
Best of luck to ya'.

Rich Stidger · Sep 19, 2009

CalebD said:
Your first steps would be to get new spark plugs, wires, points (if not electronic ignition), change the oil (SAE 30W oil - Rotella 'T' is great), new battery and spray in some MMO (Marvel Mystery Oil) into the cylinders from the plug holes - this can help lubricate the valves and pistons.

A little ether (starting fluid) sprayed on the air intake of the carb will tell you quickly if you have spark and a working starter motor when the engine turns over, even begrudgingly.

Very good procedure for getting long-idle engine up and running. I might add to check/replace the raw water pump impeller too. Lubing the engine with MMO is very important since all the internal top-end parts will be dry after a couple years

Tim R. · Sep 19, 2009

A barrel pump or similar is probably best for removing the gasoline. I used one on my Pearson 28 a few years back. It had a monel tank and I was able to remove it and get it sparkling clean inside. If yours is monel, you do not want to cut the tank out. Depending on where the filler or pickup tubes are you may be able to get a look inside and also swab out any gunk if necessary.

When working with gasoline, ensure you have removed any possibility of spark. If you need light then use an industrial grade LED that is rated for this type of work. I believe Princeton tech has one that is fairly cheap.

Check here for tons of Ericson info:

www.ericsonyachts.org

tommays · Sep 20, 2009

The A4 fuel pump has a priming lever which will start a siphon flow into a 5 gallon can lower than the tank when its full you can use the tank shutoff valve to stop the flow.

All you would need to do take off the fuel line on the pump to the carb off and use a long enough line to reach the fuel can

Rich Stidger · Sep 21, 2009

On siphoning the fuel tank- If the fuel tank is suspended from the cockpit floor or higher than the engine (it was in my Morgan 30) the tank will or should have an anti-siphon valve that will impede removal of fuel by siphoning. I would pump out the fuel using a barrel pump as previously suggested.

Ol Dave · Jan 29, 2010

A common and I mean really common way to get water in your oil is to overcrank the engine getting it started. As you grind away water is being drawn in by the fresh water impeller and pushed throgh the engine to the lift in the muffler ... where it sits until a puff of exhaust pushes it over the hump. If there is no exhaust because it didn't start, then the column of water will enter the cylinder through the exhaust valves. The water then prevents starting and will eventually work past the rings to the crankcase.

If you don't get a start right away ... say within 30 seconds ... you must cut off the water entering the engine and risk burning out your impeller vanes.

Old oil is drawn out of the engine through the oil dipstick opening with a suction pump.

Ol' Dave

Nik · Jan 30, 2010

Water in your oil... Well, what we used to do on the farm was to drain the oil. New filter (cheap one) and refill with Kerosene, disconnect the plugs and crank over and over several times (do not over heat your starter), drain and refill a few times. This will knock a lot of crap out of the oil pan and every where else. Drain again and refill with oil (cheap stuff), crank and crank. Drain, crank a couple of times, drain again, new good filter, new good oil. Good to go. Have kept tractors 30+ years old running like this. The main thing is to not RUN the engine, just get stuff flowing through and flushing the ports. The little remaining Kero, wont dilute the oil enough and it is cheap. OH, a prior post mentioned ROTELLA... Thats for Diesels. If after this you have milky oil... now you have a bigger problem...

higgs · Jan 30, 2010

I put in over 25 years cruising L Mich - 12 of it with an A4, which I rebuilt with advise and parts from Don Moyer. I think you are getting some good advise here.

The oil is pumped out through the dip stick tube. I have found this solution to be the easiest by far:http://www.yachtsee.com/pelaoilextractor.htm
You will never get all the oil out and there is no filter on the A4.

I would go to Moyer's site and ask the forum there what process is best for getting the water out. If that does not help, then call Don up. He is a great guy and always willing to help. There is a lot of knowledge at this site, but Moyer is unquestionably the guru.

I would do the several oil changes and just see how the engine responds before rushing into anything.

Should a rebuild be needed, they are not hard to do. If you are uneasy about assembling the short block, a machine shop can do that for you at a reasonable cost. It will also give you the opportunity to pull your tank out and clean up the bilge around the engine. I took my 25 year old tank to a place that did fuel tank restoration and was very happy with the results.

If you are headed out into L Mich you really want to avoid going the outboard route. Crashing into those steep L Mich seas with a10 hp, with its prop constantly popping out of the water, will make for a long, tedious haul. Distances between ports on L Mich are fairly long and at some point you will find yourself bashing it out for 6 or 7 hours (make that 10 with an ob) There is a good reason why Ericson went to the extra expense of an inboard.

Another suggestion I have is buying the CDI prop designed for the A4. I was very happy with the results. I was uneasy about it being plastic, but it performed well for me for 5 or 6 years until I sold the boat. http://www.sailcdi.com/pa4page.htm

how do you drain and clean fuel tank?

Valentina

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Don S/V ILLusion

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CalebD

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Valentina

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Rich Stidger

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CalebD

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Rich Stidger

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Tim R.

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Valentina

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tommays

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Valentina

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Rich Stidger

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Ol Dave

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Nik

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higgs

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