Merc 2006 50 hp 2 stroke carb tubing size help

[73 Dolphin]

Ok so this is going to sound dumb.... 2006 Mercury 50ELPTO 2 stroke. I rebuilt my carbs and the carb tubing supplied were the nasty EPA grey lines. I bit the bullet and used them anyway and every length of hose leaks at the clamps. It's not the right ID. Too loose.
I've tried the sprung clamps and zip ties but everything I try - it just leaks everywhere.
The originals had hardened and once removed no longer seal at the connections. Also they are not long enough to shorten and reuse.
I'm talking about the fuel lines that run from one carb to the next.
Any idea on what size internal diameter tubing I should be using to get a good tight fit and also the best clamps/ zip ties I need to use?
I think that Merc calls it carb tubing. Its sold everywhere by various part numbers.
All I have seen are only good for model years up to 1995 according to the descriptions. None of the part numbers give you any dimensions. So that's super confusing too.
I'm sure it's just tygon but I need the right size to fit snug and not drip gas!
Also I may be wrong on it being called carb tubing. lol. What seems like the simplest search turned it to a frustrating day long experience and I still don't know that I
need. It's not even listed on any parts diagram I can find.
Any help would be very much appreciated. Thanks!

 

[merc850]

Use drill bits pushed into the old lines, the one that fits is the I.D. size. The clamps used on auto transmission hoses look like a good choice.

 

[Texasmark]

Mercury zip ties are specially designed in that the locking part of the tie isn't flat but has an additional arc that, when the tie is tightened, closes the open area between normal ties locking section and strap.....to prevent your problem. If iboats doesn't have them ebay or your marine dealer can help.

 

[73 Dolphin]

Any idea of the actual size to stop me from having to go out and buy a bunch of drill bits to see if one fits?

 

[Texasmark]

Any idea of the actual size to stop me from having to go out and buy a bunch of drill bits to see if one fits?

Why don't you whack off a piece that isn't currently connected to a terminal (diameter stretched) and take it with you to an auto parts store.

 

[wn6ngp]

I'll be interested in finding out the answer to this fuel line size question. I've got an '00 90 hp version. At one time I thought I'd be proactive and change all those little hoses but I never could find the right size. The local merc dealer did not have them nor did he know what to use so I decided to leave well enough alone. Hopefully, the one that supplies the oil won't fail. If you measure the barbs the hose fits on usually the hose id is smaller so that its a tight fit even without the clamps.

 

[73 Dolphin]

Yes its nuts that the answer is so hard to find!

 

[73 Dolphin]

So I did find a drill bit that fits. The shaft measures .182" 0r 4.62mm
Neither of those is a real value. ( go figure )
So its either 11/64" = .171875" ( 4.3656 mm )
or 3/16" = .1875" ( 4.7625 mm )
Thats a .015" difference between the two.
The smaller dia is .010" under the size of the drill bit
and the larger is .005" over the size of the drill.
But the drill is a really nice snug fit.
So now I have 2 options. One may be too loose and the other too tight!

 

[73 Dolphin]

I decided to order 3/16 internal 5/16 external tygon with 1/16 wall.
I WILL report back if it works in case it helps someone else.

 

[wn6ngp]

I decided to order 3/16 internal 5/16 external tygon with 1/16 wall.
I WILL report back if it works in case it helps someone else.

You have to wonder how it was that the merc engineers came to choose that particular tubing size? Maybe someone told them that there was an excessive supply of that particular size so it would always be cheaper despite being an odd size. There seems to be a similar size of Tygon that is popular on motorcycles.

 

[ahicks]

I've found 3/16" will work, but not real well. You have to clamp everything securely. As often as I'm forced to mess with this issue, would love to find a source for something closer to the OEM size.

 

[73 Dolphin]

It's unreal that a company that has made hundreds of thousands of outboards cannot either list the tubing size or tell you what it is! There really shouldn't be any kind of issue finding it!! Hopefully the 3/16" will work. If not maybe try to find some 11/64"

 

[Texasmark]

I have an idea. They wanted you to buy OEM replacements from them so they hid the size.........OEMs do that you know.

 

[wn6ngp]

I have an idea. They wanted you to buy OEM replacements from them so they hid the size.........OEMs do that you know.

I do remember some p/n's of those hoses listed in their parts book. It did have outrageous prices for each length, not bulk. Surprisingly, pricing for oem JD Tractor parts is even worse than marine.

 

[73 Dolphin]

There's a bunch of mercury "carb tubing" part numbers. None of the 8 or so that I saw come back to my motor and the vast majority are good for model years up to 1995 for some reason. I'm not trying to find the size because I'm cheap and not wanting to pay Merc/ Quicksilver prices. It's because I just need to replace it and can't find it anywhere!!!! Trust me, if Merc made it searchable and available I'd buy it.

 

[ahicks]

Merc isn't the only one using this weird size. Honda and Yamaha are as well....

 

[Yegboats]

Looked it up w/o a serial number so numbers may not be accurate, but this should at least give you an idea where to look on the schematic. Also the numbers may match up and you'll atleast have part numbers to call around on so they can sell you a chunk. When you're looking at the part list on the schematic it tells you how long a piece you'll need so you can ball park how much you'll need. Sorry I didn't link a parts schematic I couldn't find on iboats, and not sure if its ok to post.
common tubing/bleed hose/fuel line part numbers for these engines

SIERRA P# 18-8048 OEM part: 32-99130122

Bleeder Hose​

I.D.: .090" or 2.3mm
O.D.: .220" or 5.6mm

OEM part: 9912688 not sure what size can't find Sierra, and Merc sells it in a 36" chunk

OEM part: 9912688 36" bulk

 

[ahicks]

I think the ID of the hose we're after, or at least the stuff I'm after, is going to be in the area of 5mm.

 

[Texasmark]

I do remember some p/n's of those hoses listed in their parts book. It did have outrageous prices for each length, not bulk. Surprisingly, pricing for oem JD Tractor parts is even worse than marine.

Yes, like special designs.....as an example the hose that routs oil into the gas line (a wye) from the oil pump on 2 strokers.

 

[wn6ngp]

Yes, like special designs.....as an example the hose that routs oil into the gas line (a wye) from the oil pump on 2 strokers.

I happened to have some yellow fuel line from a previous project and the id is .1875" or 4.7mm. My experience has been that when attached the fuel line expands a bit so maybe 4.7mm would be ok.

I remember looking at that oil wye hose hoping I never have to replace it. its lasted 23 years so far.