Triton fuel systems

bcooke · Post by **bcooke** » Tue May 31, 2005 12:25 pm

Okay, maybe this belongs in the Ramble (or Rant) section but it is Triton specific and sorta a question.

Did all original Triton fuel tanks come with a 1/2" NPT tank outlet fitting and a couple of reducers and did the tank vent outlet REALLY need a 3/4" NPT fitting with a stack of reducers? The fuel feed to the engine is a 5/16" hose (which agrees with Moyer's recomendations) so why the large fittings? I don't have experience with the Atomic Four's fuel burn but I am thinking 0.5 to 1.5 gallons and hour; right?

Why would the vent line be bigger than the outlet? Should the vent line be => 3/4" to handle a rapid filling of the tank or can I safely reduce the vent line to a 1/4" hose?

Is my boat the only one with such humungous fittings?

I am having another thought as I write this. My current fuel plumbing is a combination of copper pipe and hose (the pipe was simply cut and hose clamped over it; no bulbs, no barbs, no nothing on the pipe to help seal against the hose - that would explain the fuel stains on the hull...). I was going to go with an all hose fuel system, clamping the hose to hose/pipe adapters as opposed to threaded fittings. Is that okay or should I be thinking a flared/threaded hose or all pipe fuel system? Are there regulations on this? How are the new boats generally plumbed for fuel?

Come to think of it, does anyone supply pipe thead-to-flared/threaded hose connections in the marine world? I haven't seen them in the catalogs.

I guess I did imbed a few questions in my rant...

-Britton

Post by **Tim** » Tue May 31, 2005 1:18 pm

Seeing old fuel systems like the one you describe makes it oh-so crystal clear why onboard fires occur. They are sadly common.

Vent lines are typically larger, and need to be at least 5/8" hose diameter for ABYC standards. Most stock hull vent fittings take 5/8" or 3/4" hose to accommodate this standard. The other fittings are unnecessarily large, and were likely installed because "they were on hand".

Barbed connections and standard SAE J1527 fuel hose (USCG Type A1) are definitely acceptable for all aspects of your fuel system, and is the widely-applied method of installing new fuel systems. There's no need to use copper tubing, or flared/threaded connections. You can use all the standard brass barbed fittings available anywhere in your system.

Ordinarily, I would have said 1/4" fuel supply hose, but if Moyer says 5/16" for the A4, then that is the route to take. Small diesels normally take 1/4".

By the way, don't use any Teflon tape on the threaded ends of the fittings; the tape can break down and omit little particles into the fuel. Instead, use pipe dope as a thread seal.

bcooke · Post by **bcooke** » Tue May 31, 2005 2:02 pm

Hey Tim, thanks for the quick reply.

I am glad the barbed fittings will work since I just spent the morning figuring out what I need and ordering all the connectors.

True to form my fuel system was held together with Teflon tape. I was trying to hunt down a sealant called "Fuellube" that is widely used in aircraft fuel systems. Strangley, I can't find it anywhere and I am thinking it has been superceded in the last couple of years (a can of Fuellube lasts for years and years...) Pipe dope it is then.

I am going to have to do some more hunting for a vent fitting I guess. The orginal fitting (that was bypassed) was set up for a 1/4" or 5/16" hose with a guard or cover over the fitting and mounted on the transom. It sounds like a 5/8" or 3/4" fitting is going to need something bigger unless I just screw in a 5/8" fitting into a bed of green epoxy against the inner hull. That would be cute. I think that is how Pearson did it too unless the PO had to repair it at some point.

On a rambling note, I think I broke my record today. I couldn't finish up some glass work and I couldn't paint/varnish as planned today because of the weather so I took to ordering supplies... I think I am up to about $1000 for the week and I am debating on another couple of hundred. before the day is out. Let's see, that makes the cost of this rebuild on a sail-away condition boat so far...
Well, that is enough of that! My only consolation is that with the Daysailor nearing completion you must have me beat handily...
The good news is that by the end of the summer I will have enough inventory to go into business for myself. My house is starting to look like a hardware/chandlery shop. I have boat parts and boxes of consumables everywhere.

I think my credit card has cooled off so I had better get back to work.

-Britton

bcooke · Post by **bcooke** » Tue May 31, 2005 2:06 pm

Ahh... when you wrote 5/8" vent line you were thinking hose size not NPT sizes... I guess I will keep the reducer fitting stack-up then and the vent fitting should be easier to locate :-)

-Britton

Post by **Tim** » Tue May 31, 2005 2:53 pm

Yes--I was talking about hose ID. Sorry for any confusion.

I don't want to talk about my expenditures on the Daysailor over the past couple months...I am in denial.

bcooke · Post by **bcooke** » Tue May 31, 2005 3:30 pm

...I am in denial

Hehe,

Works of Art and other important contributions to culture and society-at-large should not and can not be profit driven. You are an inspiration to us all :-)

At least you have a chance of maintaining a legitimate business with your inventory. I can only pretend that the crate of sandpaper I just bought will make me money someday. At least I won't have to run to the hardware store and grumble about the poor quality selection every other day... at least I hope!

-Britton