Cracked Remote Oil Tank

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
floater
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Cracked Remote Oil Tank

Postby floater » Tue Sep 19, 2017 7:34 pm

When I was washing the Revenge today ,I notice a blue spray of oil on the starboard side where I have the remote oil tank mounted. After checking all the lines and caps, I noticed a 2-inch crack in the side of the oil tank about an inch from the top.

I've been pricing out a replacement tank and after exchange and duty I'm looking at close to CA-$200. I've seen a few videos on repairing this type of tank with a piece of polypropylene hose and using it as a weld stick. Has anyone attempted this?

I fear to use the boat now as the oil tank may not be getting enough pressure to fill the tank on the engine.

jimh
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Re: Cracked Remote Oil Tank

Postby jimh » Tue Sep 19, 2017 11:25 pm

What engine is involved?

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Dutchman
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Re: Cracked Remote Oil Tank

Postby Dutchman » Wed Sep 20, 2017 8:56 am

Plastic welding is an art and you must have the same material weld stick as the oil tank. After you figure that out then applying the right heat to fuse the two together will not be easy.
I don't know but you might be able to find a two part type glue/epoxy that could do the job. Search your local hardware store.
All could be a less expensive try before spending CA$200.
Good luck
EJO
"Clumsy Cleat"look up what it means
50th edition 2008 Montauk 150, w/60HP Mercury Bigfoot

floater
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Re: Cracked Remote Oil Tank

Postby floater » Wed Sep 20, 2017 4:04 pm

Motor is a 1991 Mercury 200.

I fixed [the crack in the oil tank] today. I removed and drained the tank, and then cleaned the outside. I roughly sanded the area around the crack. I lit a piece of polyethylene tubing on fire and it dripped like a candle. I filled the crack and surrounding area. Let it cool. I rough sanded the surface and reapplied more poly. I did this four times and it made a nice thick seal.

I then installed the caps and put 20-PSI of air pressure into end of the hose; then submerged the tank into a bucket of water. The weld seems to be holding nicely. Quick fix--and now I'm storing a piece of the poly on board for any future repairs that may arise.

jimh
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Re: Cracked Remote Oil Tank

Postby jimh » Wed Sep 20, 2017 4:23 pm

Your polyethylene welding was a novel solution.

Re the Mercury engine: in the Mercury oil mixing system they pressurize the tank above atmospheric pressure to create movement of oil. Maybe the pressure regulator allowed too much pressure to accumulate. But if your repair held at 20-PSI positive pressure above atmospheric, I'd say the leak has been fixed.

floater
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Re: Cracked Remote Oil Tank

Postby floater » Wed Sep 20, 2017 6:41 pm

Tomorrow will tell as I'm taking it out for spin to be sure. THanks

Jefecinco
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Re: Cracked Remote Oil Tank

Postby Jefecinco » Thu Sep 21, 2017 9:11 am

Floater--if you have a portable fuel tank you can mix a few gallons of fuel and oil to the proper ratio for your engine and take it on your test voyage. If the tank repair fails while you are testing you'll then have a supply of fuel to get you back without damage to the engine.

You may need to cut into your fuel line above the primer bulb to connect the portable tank or take along a spare fuel line to connect the portable tank directly to your engine. If you have to cut the installed fuel line you will need a nipple and two pairs of hose clamps to put it together again. I would take along a spare line with bulb to avoid having to cut the line.
Butch

floater
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Re: Cracked Remote Oil Tank

Postby floater » Thu Sep 21, 2017 4:56 pm

Thanks for the Tip Jefencinco. I went out and after about ten minutes the repair started seeping oil below the patch. Looks like it managed to squeeze out beyond the crack and slip under the patch. It wasn't too bad and I was able to go about my day fishing. I took another look when I got back home and the tank is now cracked in another location. I've called the local marina and they said they have several used ones they would be willing to pressure test and sell me. Thanks

floater
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Re: Cracked Remote Oil Tank

Postby floater » Fri Sep 22, 2017 5:07 pm

I bought a used remote oil tank from aocal marina for $25. I just needed to clean out all the Opti Oil and it was good to go. I reground out the patch on the old tank and used JB Marine Weld this time around. I drilled either end of the crack and then used two coats. I will keep this tank as a back up. The tank I got from the marina is in better shape than mine; it looks like it was kept inboard and out of the sun. My tank is mounted in the splash well and you can see cracking in the plastic. Check your oil tanks if you keep them exposed to the elements.

jimh
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Re: Cracked Remote Oil Tank

Postby jimh » Sat Sep 23, 2017 6:13 am

Thanks for the follow-up report on the failure of your unusual repair method to hold up in normal use. In electronic work, the repair method you described would be called a cold-solder joint. Generally when making a weldment or solder connection, the material being welded or soldered must be brought up to high temperature so that its material will become fluid and chemically involved in the bond with the welding rod or solder.

floater
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Re: Cracked Remote Oil Tank

Postby floater » Wed Sep 27, 2017 8:07 am

I heated the cracked area with a heat gun until it got soft and then I applied the polyethylene. I didn't want to heat the tank any more than that for fear of making the hole any bigger.

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Dutchman
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Re: Cracked Remote Oil Tank

Postby Dutchman » Thu Sep 28, 2017 1:41 pm

Let us know if the JB-Weld will be holding. Can you do a test as you did after the drip repair? It will be good to know for some skippers to keep the two tubes of JB on board.
EJO
"Clumsy Cleat"look up what it means
50th edition 2008 Montauk 150, w/60HP Mercury Bigfoot

floater
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Re: Cracked Remote Oil Tank

Postby floater » Mon Oct 02, 2017 10:26 pm

I haven't retested the JB Marine Welded tank as of yet. I put the used one in and it works like it should and doesn't leak. I will put the repaired one back in before I put it away for the winter and post back.