fuel sending unit

I have a 2002 Key Largo 180 that is leaking fuel from the sending unit. The sending unit is only a few months old however some of the inserts in the plastic tank are stripped. When ever I over fill the tank or when the boat is on an angle (boat ramp/driveway) it leaks fuel. I purchased some Life Seal sealant from West Marine as they recommended but I'm not sure that this is the right product for this application. Also should I discard the gasket or use the gasket along with the sealant?
Thank you.

Re: fuel sending unit

Are you saying that one of the screws that hold the sending unit in place is stripped out? If so have you tried an oversize screw? As far as the sealant i would get a new gasket (clean and dry) and use it with a thin layer of the sealant. Be sure to allow enough time for the sealant to dry properly before using the boat. Hope this helps.

Re: fuel sending unit

Lots of luck. Permatex makes a putty like sealant in a tube. I forget which, but I am referring to their product identified by either a #1 or #2 sold in auto parts stores. One of them remains pliable and the other gets hard. You want the pliable one. The product is not affected by fuel. I would use the gasket and the sealant but you probably will get nowhere.

Best thing to do is to fill the fuel tank to force out vapors.....gasoline doesn't explode, vapors do. Get the next size larger drill/tap and drill and tap the stripped holes inserting new ss screws to fit. I wouldn't worry about filings falling into the tank as there are several filters prior to any reaching your engine and being metal they will settle to the bottom of the tank.

Mark

Re: fuel sending unit

Texasmark said:

Lots of luck. Permatex makes a putty like sealant in a tube. I forget which, but I am referring to their product identified by either a #1 or #2 sold in auto parts stores. One of them remains pliable and the other gets hard. You want the pliable one. The product is not affected by fuel. I would use the gasket and the sealant but you probably will get nowhere.

Best thing to do is to fill the fuel tank to force out vapors.....gasoline doesn't explode, vapors do. Get the next size larger drill/tap and drill and tap the stripped holes inserting new ss screws to fit. I wouldn't worry about filings falling into the tank as there are several filters prior to any reaching your engine and being metal they will settle to the bottom of the tank.

Mark

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Thanks for the replies,
Not sure I can get a drill in there, maybe a small right angle drill. A lot of fuel has leaked into the bilge so there are a lot of vapors. Someone else has also recommended the permatex product. I'm not sure if I can retap the holes without predrilling them first but that would be the ideal.

Re: fuel sending unit

Run a bunch of water mixed with dish soap through the bilge to get rid of the residue and eliminate the fumes....... worst case scenario is to remove the tank to repair it.

Are the screws into plastic or metal?

Re: fuel sending unit

If possible I would flush the bilge out first. And after that I would drill and tap by hand . No power tools. vapors and electric motors are deadly. And be damn careful with the boats electric power. You have a potential bomb there.

Re: fuel sending unit

the other possibility if you are concerned with explosions/ignition...... remove ALL the fuel and fill the tank with water all the way to the top before you do the work....... drain dry and refill

Re: fuel sending unit

There are metal inserts in the plastic tank. I just spoke with my brother-in-law who is a machinist and he told me to find out the thread size and I should be able to retap by hand and install helicoils. I've never used them before but it sounds like it may be the way to go.

Re: fuel sending unit

marshman10 said:

A lot of fuel has leaked into the bilge so there are a lot of vapors.

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To help with the fuel spill in the bilge, when my Maxum had a tiny fuel leak from the cool fuel cell, I used a product called PRP SoyPowder Oil & Fuel Absorber that seemed to work pretty well. Just sprinkle it in and it absorbs the fuel.

For the vapors, I would think as long as you have the engine compartment wide open and plenty of air circulating, you would be fine during the repairs.

Mark

Re: fuel sending unit

marshman10 said:

There are metal inserts in the plastic tank. I just spoke with my brother-in-law who is a machinist and he told me to find out the thread size and I should be able to retap by hand and install helicoils. I've never used them before but it sounds like it may be the way to go.

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The helical coil (helicoil) is a thread used to repair a thread. In some cases, you can screw the helicoil thread , sized to match the existing thread, into the existing thread and then use a smaller screw that fits the reduced threaded internal diameter of the coil to secure your flange. If the same size screw is to be used, the larger diameter helicoil will need the hole drilled and tapped to accept the HC outer thread and then the existing screw size can be reused. In the latter case, the hole and tap will be larger than the next size screw would be if you drill/tapped for that.

I wouldn't attempt to tap a larger diameter without drilling first.

SAE Machine screws:

#8-32, .164 diameter, 32 threads/inch (UNC), tap drill dia. #29, (.136)
#10-32, .190, 32 threads/inch (UNF), tap drill dia. #21, (.159)

Helical Coil for specified machine screw:

For #6 screw, helical coil tap size (regular tap just used for the HC thread), #17 (.173). Helical coil .164-32 UNC-2B thread.
#8..............................................................................................#7 (.208).....................190-32UNF-2B thread.

Some auto supply stores sell the coils and will rent/loan you the insertion tool. To use it you need vertical clearance of approx 6-8". You load the coil into the insertion tool, place it over the hole and with downward pressure on the tool, screw the coil into the hole till the tool breaks loose. When finished (top of coil is flush or just below mounting surface) with a suitable punch, stick it in the hole and with a sharp rap from a hammer, knock the tang off. Then just screw the appropriate screw into the coil.

On fumes, a good bilge cleaner will also work to remove the fuel, being drained out the bilge drain hole, then a wash down of the area to finish the job, then an external fan/blower out of range of the fumes but directed into the bilge until you cease to smell fumes.

On the tank if you don't want it full, empty it and fill as others have said or fill with inert gas. One easy to obtain inert gas would be engine exhaust, or nitrogen gas.

HTH,
Mark

Re: fuel sending unit

This problem is very common with any plastic fuel tank. .........STOP BUYING unreliable plastic tanks.............The slave labor used to make them is paid by the number of tanks they produce. Good or bad. Plastic is a ***** to repair reliably. As you are finding
out
We are talking about leaking bombs in a boat............

There are metal fuel tanks to handle Ethanol gasoline.

Re: fuel sending unit

cyclops2 said:

This problem is very common with any plastic fuel tank. .........STOP BUYING unreliable plastic tanks.............The slave labor used to make them is paid by the number of tanks they produce. Good or bad. Plastic is a ***** to repair reliably. As you are finding
out
We are talking about leaking bombs in a boat............

There are metal fuel tanks to handle Ethanol gasoline.

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I have a plastic tank that has been in the boat since 2000. No problems. I have looked the company up on www and they build a lot of tanks for a lot of boats in a lot of volumes and shapes.

Have no idea as to where they are made nor who makes them.....but what's your point??????????

Re: fuel sending unit

All 3 Moller tanks leaked. Plus other people where I stay have leaking Moellers or other brands.

Forget about ever tightening the caps. They become footballs & roll on their sides leaking.
Leave the caps loose & fuel comes out the cap & makes lots of fumes in 85 degree heat if the boat has any pitching or turning.

A Fiberglass fuel tank is a far sturdier tank when it comes to fittings. All the built in ones I have worked on have not had overtightened screws strip metal or the plate screw threads.

My point is plastics........True USCG approved plastics are not always rigid enough for fuel tank use.

Re: fuel sending unit

You made a very good point about your 2000 tank. The age of it. Better quality is so common back then.