Fuel line size

[Streffpilot]

What is the best fuel line size for between the carbs and fuel pumps on. 1972 Mercury Thunderbolt 115 hp??

 

[minuteman62-64]

Re: Fuel line size

Same size as installed at the factory? Or larger. Not smaller.

 

[Maxz695]

Re: Fuel line size

I think the fittings are for a 1/4 hose. Use clamps (Stainless) not zip ties as if they leak it,s a pain to remove fix and reassemble

 

[Texasmark]

Re: Fuel line size

5/16 for my 90, was 3/8 on my 115 tower.

Mark

 

[Maxz695]

Re: Fuel line size

3/8th at the carbs on a 115 wow. Guess the fuel milage isn.t good just saying thats a a big flow. I guess that would be the same at the primer bulb?

 

[Texasmark]

Re: Fuel line size

3/8th at the carbs on a 115 wow. Guess the fuel milage isn.t good just saying thats a a big flow. I guess that would be the same at the primer bulb?

Well sir, with your response I re-read the question and mis-quoted. I was addressing the fuel line to the engine. My 90 currently is using 5/16. I know that because I used the same piece of hose that I used to re-plumb the fuel from the tank on an inner hose that split at the output of the oil pump.

Mark

 

[mercurymang]

Re: Fuel line size

I had the same question recently on my 650. What came off showed to be 1/4" ID. I went down to the auto parts store to get some and came home with 1/4" tygon. I really like it as I can see the fuel. I have since read the tygon will get hard after a year or so I don't know how long I will keep it. The other thing was that although it showed to be 1/4", it looked visibly to be 3/16" and it was hard as heck to get over the nipples. I was concerned about putting too restrictive of a diameter hose on. I measure the fuel nipples and it showed to be closer to 1/4 than 5/16. Bottom line is couldn't really get a straight answer anywhere and even my manual did not list what size fuel line to use. I think sooner or later I will go and get some 5/16 and if it fits I'll go with it. If not, I'll go with the 1/4. My line of thinking is that you can't go too big (as long as it doesn't) leak.

 

[Maxz695]

Re: Fuel line size

It,s cool He was inquiring about the carb fitting to the fuel pump. There may be a srtainer between them or an inline filter. My 70 is right with 1/4 fuel line at the carbs to the fuel filter and to fuel pump.. From my pump to my quick disconnect inside is also a 1/4 line but on the other side of the connector it is 5/16 but can use 3/8th. I have 3/8th from tank to primer bulb with 3/8th nipples on the primer bulb. I would be eary to use a smaller hose than 1/4 as it might fit tighter, but it might or might not limit or restrict the fuel flow. JMO