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Fuel Tank Access Ports, Pickups and Cleaning

3K views 15 replies 7 participants last post by  Plumbean 
#1 ·
I ran into some fuel problems at the end of the summer, so I've decided to clean out my fuel tank. It is a relatively new (2009) 18 gallon aluminum fuel tank and I have already removed it from the boat and have it in the garage. Hoping to get some advice from those who have gone before ...

Here are my questions:

1. Has anyone installed a SeaBuilt access port before? Annoyingly, my tank does not have an access port other than a port for the sending unit. I've looked in there and confirmed that there is some sludge in the tank. Not too bad, but could use a cleaning. So to make this happen, I need an access port, and the only game in town seems to be SeaBuilt. If anyone has experience with these, I'm all ears.

2. Has anyone ever retrofitted an extra pickup and return into an aluminum fuel tank? I'm thinking of adding a polishing system, but would need to add a fuel pickup and return. I've seen one company that makes retrofit ones similar to the SeaBuilt access ports (i.e. -- not welded on but through bolted instead). Curious if anyone has used these before.

3. Once I get in there, I plan on wiping it down, then cleaning with dawn dish soap and then (if I can sneak it out of the house without the wife seeing it) using our steamer to steam clean it. If anyone has thoughts about this part of the process, I'm all ears.

Thanks in advance!
 
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#2 ·
If the top of the tank will be accessible when replaced you could cut out a round hole which includes the sending unit. Drill an Al plate for the sender and any other attachments. Plate over laps the hole Drill and tap tank for SS fasteners, Neoprene fuel resistant gasket. If tank is delicate make hole oval and tap the plate, bolt with fender washers on the tank.If the tank is sound ,why not just clean it and T off the existing fittings for polishing.
 
#4 ·
Thanks. This may be an option. I don't want to tee off the existing pickup because I would like the polishing system to have a pickup closer to the bottom of the tank than the one for the fuel pickup leading to the engine.

Since I have the tank out, I may just find someone that can weld two bosses into place.
 
#3 ·
I did a project similar to what you describe. I am repowering with a diesel and replaced the steel fuel tank with a 30 gal aluminum one. In the process I installed a hand hole and a separate polishing system. While I’ve checked all the systems individually, the engine isn’t yet in so I don’t have a full op test.
The tank was new, with three threaded bosses welded into the top. I needed to accommodate the following: a hand hole, a level sensor, two suction lines (one for the engine and one for the polishing system), two return lines (one for the engine and one for the polishing system) and the vent. I used a circle saw to cut a handhole. That circle that was cut our included one of the welded bosses. To cover the handhole I cut a circular piece of equally thick aluminum plane which is held down with ten bolts around the perimeter which are threaded into the top of the tank. The gasket was cut from 1/8 th nitrile rubber which is supposed to be better for fuel environments. The tank sensor is mounted into the hand hole cover. Since the sensor included a port for a fuel line I used this for the engine return. One of the bosses was used for the engine suction. As I had the disc that I’d cut out with a boss in it, I cut a second hole in the tank top to mount it. This being smaller it used five hold down bolts. The suction for the polishing system was mounted on this boss. The other boss in the tank top was used for both the polishing return and the vent. The arrangement is a T threaded into the boss with the return fitting going into one arm. The second arm has an elbow with a vent hose going up from it for about a foot before it turns. The manufacturer recommended this arrangement.
Some other things: I used 1/4 in aluminium bolts and aluminium pipe fittings where they screwed into the tank. I tested the penetrations for tightness with about a 10 foot standing head of water. I also pressure tested the tank to its as built pressure with a bicycle pump. I also calibrated the level gage with water so I know how many gallons equated to what level indication. This caused me to have to replace the sensor as it wasn’t designed to be in a water environment. A better way would have been to record the inches of water with gallons put in and use that data to calibrate the level gage indications to gallons. I set the engine suction pick-up at 3 inches above the tank bottom and the polishing system at ½ inch from the bottom. The fuel system is set up so that you can shift between the suctions if needed, since there’s about five usable gallons below the high suction that you can get with the low suction. Shifting to the low suction also shifts the engine suction to the polishing system’s RACOR 200 FG filter. This allows you to shift to filters when the engine’s RAYCOR 500 is clogged and you want to keep the engine running on the RACOR 200FG filter. The polishing system pump is set up to run when the engine is running or off a timer when the engine is not. The filter vacuum gage can be shifted between the engine filter and the polishing filter.
 
#5 ·
Walt:

Your system sounds nice but also pretty complicated. I think I'd need to see a diagram to figure out how you have it set up, but I like the idea of having the polishing system run automatically when the engine is running. How did you wire that?

Plumbean
 
#6 ·
I suggest that the access port have a backing plate for the screws. Unless the tank skin is unusually thick the screws will strip out too easily. In aluminum there should be five threads engaged to prevent stripping. Measure 5 threads of the chosen screw.

A cool as a polishing system might be, all you really need is to use a suction pump to suck clean the tank's sump once or twice a year. It just simple maintenance. Do it every oil change. Keeping the water to a minimum is all that is needed for shiny clean fuel. The growing crud is not in the fuel, it is at the interface of the fuel and water...in the sump. The hard varnish-like accumulations on the tank walls do not normally cause any clogging, and polishing doesn't remove them anyway.
 
#7 ·
I agree about the backing plate, which is how the Sea Built access plates are constructed. As for the polishing system, I have not yet decided if I'm going to bother. However, I already have a Walbro pump that I can use for it, and since the tank is out of the boat now seems like the time to weld on a couple of bosses if I want to go that route.
 
#8 ·
wiring the polishing system pump: one power source is the engine power. this is the circuit energized when I turn on the ignition switch. This means the polishing pump is running when the engine is running. The second power supply is from the house bus that powers the lights, and miscellaneous electrical equipment. A switch selects the source. The house power comes through a manual timer full turn is one hour. The reason for this is to be able to power when the engine is off but not be able to leave the polishing pump on unatteneded for a sustained period. The concern being that if a hose let go I'd pump fuel into the bilge and the bilge pump would put it into the harbor. Don't see the need to weld in bosses if you have a handhold since you can bore and install a hole insert a pickup tube fitting as you can reach it to put in a nut from inside the tank.
 
#10 ·
I just use a manual mechanical timer from the haedware store. Since it'spring operated it's ok with 12V DC. Works fine. I mounted it on a weather proof covered plastic electrical box also from the hardware store. The fuseholder for the pump, the three way power switch (engine-off-house), a pump running light and a light for high water in the RACOR are also mounted in the box. The RACOR high level feature was in the 200 filter which is no longer being made. I'll send a system diagram when I can get in a format that cam be attached. I have a detailed write up e.g. operating procedures for the system i can send if you want.
 
#11 ·
Here's the diagram of my system. Someone asked. A note... it shows a check valve in the polishing system. That's because it's built into the pump. It's not necessary I had originally wanted the polishing system and the engine return to use the same discharge into the tank. To prevent pushing fuel back into the engine when it was secured that required a check valve on both the polishing system and the engine system return. Beta said don't put a check valve in the engine return. I thing the issue is that if the check valve stuck closed it could harm the engine.
You mentioned welding in bosses. With a hand port theoretically you could just bore a hole near the port, insert a fitting within reach, and use a nut in the tank to hold it down. The problem is finding pipe fittings with straight threads. All I've found are NPT tapered threads. I suppose you could take a brass tapered NPT fitting then use a die to cut straight threads into the fitting and simply drill a hole and install the fitting using a gasket to seal it. Be a lot less cost than welding.
 

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#12 ·
Why have two different sized filters? Wouldn't it be better to have them both be the same for commonality of parts and spares? In addition, I don't see a vacuum gauge in the system. One with a drag pointer needle that stays in place after engine shutdown is better as you don't have to check it while running under load, rather you can keep track of the maximum vacuum pressure ever recorded while you were running under load.

MedSailor
 
#13 ·
Two identical filters would be better. I had a 200FG already so used that for the polishing system and got a new larger 500FG for the engine system. The 200 is out of production so the only option for a new filter was the 500. The item shown attached to the three way valve is a RACOR/Parker "T handle" vacuum gage designed to go with the thier filters. It's mounted on a three way valve so you can align the gage to either filter. Normal running is for it to be on the engine filter.
 
#14 ·
Did that job a few yrs ago. You are gonna want to position the new access port so that you can get to and clean both sides of the tank - there is a baffle in the middle of most tanks. Get a product call Marine Clean POR15.It will dissolve everything and make the tank look like new. Make sure you follow the directions - I did say it will dissolve everything including the tank - not telling how I know that:) Then cut an oversized cover and we used RivNuts to attach with. They are a threaded poprivit that you mount in the body of the tank and your fastners thread into them. then use a good neoprene fuel safe gasket material to seal.
POR-15 Cleaner Degreaser
One supplier of rivnuts Your source for Rivnut® engineered fasteners and installation tools - Cardinal Components

Peter
 
#16 ·
Just closing the loop on this. I've decided to forego installing a polishing system for now. With easy access to the tank, I figure I can always drain it and clean every couple of years, and if I run into a problem again I can pull the tank easily (about an hour's worth of work) and have additional fuel bosses installed and do the polishing system then. Too many things on the to do list I guess.

So last week I cleaned the tank thoroughly using water and Dawn dish detergent, and after a good rinse, I steam cleaned the inside. Today, I finished installing the Seabuilt Access Plate. Very nice product and pretty easy to install. I opted for the 8 inch model that requires a 6 inch hole. If you have the space, I definitely recommend this -- it would have been much more difficult to clean the tank using a 4 inch hole. I hope to reinstall the fuel tank tomorrow. The fuel I pumped out looks quite good, actually. No haze at all. I'm going to treat it anyway and then pump it back into the tank (through a filter) and use it up next season. Here is a pic with the access port installed:



Thanks to everyone for their input on this project.
 
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