Run Merc 3.0LX on external fuel tank

[Scott06]

When you say "remove the fuel from existing tank and clean it out," do you mean clean out the fuel and return it to the tank, or do you mean clean out the tank?

Depends on what you find when you empty the tank.

Empty all the contents. When I have this with old cars and rusty steel tanks I have used my vacuum extractor to suck it out, put it in covered 5 gal buckets And let it settle out. in my case I let the rust and Schmeg settle, sucked of the top couple gallons and ran it through a paint filter and used it. If it were phase separated with sludge use it to light bonfires.

once tank is empty take a look at what’s in there may be able to flush it in place or may have to remove tank and really clean it. Then take all fittings apart and replace any hoses, screens pickup tubes that are clogged etc anitsiphon is a big one.

had this years ago on my grandfather boat. Cleaned whole fuel system replaced the lines , rebuilt carb new points ran like a top

 

[MikeDobbs]

Depends on what you find when you empty the tank.

Empty all the contents. When I have this with old cars and rusty steel tanks I have used my vacuum extractor to suck it out, put it in covered 5 gal buckets And let it settle out. in my case I let the rust and Schmeg settle, sucked of the top couple gallons and ran it through a paint filter and used it. If it were phase separated with sludge use it to light bonfires.

once tank is empty take a look at what’s in there may be able to flush it in place or may have to remove tank and really clean it. Then take all fittings apart and replace any hoses, screens pickup tubes that are clogged etc anitsiphon is a big one.

had this years ago on my grandfather boat. Cleaned whole fuel system replaced the lines , rebuilt carb new points ran like a top

OK thanks, I appreciate the info.

 

[MikeDobbs]

One last question for anyone following this thread.

Where is the safest place to put the external fuel tank while underway?

My boat is a pretty typical 90's 18ft I/O bowrider except for the stern. The stern has a solid engine cover all the way across the beam (similar to the picture I'm posting), and under that cover there are partitions separating the engine bay from the storage on either side (this is not an airtight seal, just a physical partition.

I can envision 3 places to potentially store the tank.

1) On the deck, inside the part of the boat where passengers sit (cabin)

2) On the back seat of the boat

3) In either the port or starboard storage under the engine cover. This would obviously be the most convenient, but I'm concerned about vapors venting from the tank into the engine compartment. For that reason I'm thinking in the cabin or on the seat would provide better ventilation.

Thank you in advance.

 

[Chris1956]

You can probably reuse the fuel after filtering it and pouring off any water and water+alcohol, however, you need to at least smell it to determine if it is still good.

Bad fuel has a castor oil-sorta smell. That you should use to start campfires, if it still will burn.

Worse comes to worse, you could mix it in small batches with fresh fuel, if it is not too bad.

When I drain my built in tanks, I pull the fuel level sender, stick a shake-shake siphon into the tank, put a piece of 1/2" pipe in the other end of the siphon hose, since that fits thru the garboard drain, and start the siphon. Then you put Jerry cans or the like under the garboard drain (with the pipe sticking out) to catch the fuel. Make sure to keep the siphon on the bottom rear of the fuel tank (trailer tongue up a bit) to get the water sucked out.

 

[MikeDobbs]

I am new to these outboard fittings, and when I connect the fitting to the tank there is a little play (as can be seen in video).

Is this normal, or is there an issue with this fitting?

Thank you.

@Chris1956 @Scott06

 

[cyclops222]

It is normal. On all of my 5 same type of tanks & fittings. There are tiny O rings still doing the job 38 years old.

 

[Scott06]

yeah the cheaper ones do that as long as the seal inside the fuel side doesn't pull air you are fine

there are probably better and more expensive ones out there but probably ok for a test

 

[MikeDobbs]

OK, thank you both.

 

[Chris1956]

Gee, the fitting looks good. Is there a tube into the fuel tank to suck up the fuel? New tanks have that, used tanks, who knows.

 

[MikeDobbs]

Gee, the fitting looks good. Is there a tube into the fuel tank to suck up the fuel? New tanks have that, used tanks, who knows.

Yes, thanks for checking. It's a new tank, and I had to pull the assembly to get enough clearance to install the fitting, so I double checked the pickup tube while it was out.