Fuel line size issue.

[sutor623]

Hey guys I have a '84 75hp evinrude. I changed all the fuel lines when I did a fuel system overhaul. 5/16" goes into and out of the fuel pump, then that goes into a T turning into 5/32" and goes to the three carbs. It is only a short run of 5/32". Anyways all I could find is 1/8" (4/32"). It will fit over the same connectors just a bit tighter. Do you think that this will cause a fuel delivery issue? If I did would engine run lean or simply just big down under heavy throttle? On here you can see the short run I am talking about. Part numbers 8,9 and 44. Evinrude Intake Manifold Parts for 1984 75hp E75TLCRD Outboard Motor

 

[F_R]

Re: Fuel line size issue.

My guess is that the 1/8" will pass enough fuel. My bigger concern is hose kinking. The correct hoses are molded. If you bend a regular hose that sharply, it may kink and close up.

 

[sutor623]

Re: Fuel line size issue.

Cool thanks for the feedback. There is no hose kinking, they turn the corners well. I just do not want to be running lean and not know it. I guess if this doesn't pass enough fuel it would just bog down rather than run lean?

 

[boobie]

Re: Fuel line size issue.

I would say get the 5/32 " as the factory put them on for a reason. A mtr can run lean and you won't realize it.

 

[sutor623]

Re: Fuel line size issue.

Dammit!

 

[sutor623]

Re: Fuel line size issue.

I would think that with too small of a fuel line symptoms (if any) would be that of fuel starvation. The bowl will either have enough fuel in them to run properly or not. Kinda like symptoms of a bad fuel pump. Either way I think I going to keep my eyes open for the proper size, although I think this would work if I had to use it.

 

[boobie]

Re: Fuel line size issue.

It's your choice but I've seen too many mtrs running on the the lean side and the owner thought they were running great until they seized and blew a piston. What ever.

 

[sutor623]

Re: Fuel line size issue.

It's your choice but I've seen too many mtrs running on the the lean side and the owner thought they were running great until they seized and blew a piston. What ever.

Yeah I hear ya. I'm goin out to look for the 5/32 line today. It'd be a pretty silly scenario if I were to damage a motor over a $2 piece of hose.

 

[AlTn]

Re: Fuel line size issue.

fuel injection hose will have a thicker wall if that's necessary to help prevent the kinking..fwiw

 

[gm280]

Re: Fuel line size issue.

If you would do a little math, even 1/32” increase in diameter allows a significant change in flow. So I would at least use what the manufacture used as a replacement fuel line size. Going large is no problem, but smaller could change things that you may never even be a where of. And those issues are even more alarming with larger displacement engines too... While you could start your engine at home on muffs and everything seems okay, it changes under a load in the water. JMHO!

 

[sutor623]

Re: Fuel line size issue.

I looked on Ebay, there is not much 5/32 to choose from. Most of it is actually made by bombardier for Johnson/Evinrude. I found some gasoline/diesel line called Tygon. It is a green color, and supposed to hold up to the elements really well. It is translucent so that is kind of cool, at least I can tell if there is air in my lines. Ill get some pics up once I get the fuel line in. Thanks for all the thoughts/input fellas!

 

[gm280]

Re: Fuel line size issue.

Some of those fuel lines you are see on Ebay, like Tygon for instance, is/was made for 2 cycle yard equipment. That's not to say they won't work for your outboard, but just to let you know they may or may not be okay for a pressurized fuel system. Make sure they can be used without issues if you choose to go with any of them. They could be great, just make sure they can handle the fuel pump pressure without bulging out the fuel line walls diminishing the pressure at the carb... I usually go to an auto parts center and take the fuel line with me and they usually have a roll of different size fuel lines to select from. I’m sure that size is one of them too, and if not you can always go a little bigger size... JMHO!

 

[sutor623]

Re: Fuel line size issue.

Well I tried going a little bigger, which is 3/16" and it is too big to fit well on the nipples. They have vacuum line that was the proper size, but its not meant for fuel pressure. No auto part stores even carry 5/32". It is a very rare size.

 

[RogersJetboat454]

Re: Fuel line size issue.

No auto part stores even carry 5/32". It is a very rare size.

Could also consider checking with either a small engine repair shop, or a motorcycle shop. May have rolls of it that they could knock you off a couple feet from.

 

[sutor623]

Re: Fuel line size issue.

Could also consider checking with either a small engine repair shop, or a motorcycle shop. May have rolls of it that they could knock you off a couple feet from.

Yea that sounds like an idea. I already ordered a few feet of the tygon. Supposedly that stuff is pretty indestructible. I guess we shall see......

 

[gm280]

Re: Fuel line size issue.

Well I tried going a little bigger, which is 3/16" and it is too big to fit well on the nipples. They have vacuum line that was the proper size, but its not meant for fuel pressure. No auto part stores even carry 5/32". It is a very rare size.

Are you talking about inside diameter or outside diameter with the 5/32" tubing you are looking for? Reason I ask is because going from 5/32" to 3/16" is merely 1/32" change in diameter. I can't see how that small amount of diameter change would not fit on the nipples without any problems. That would only be 1/64" larger all the way around. That is minuscule in size difference between those two sizes and it would seem the 3/16? I/D could be used and even tightened up without any problem. As stated above, take the old fuel line to a motorcycle repair shop or even a lawn mower shop and see what they offer. This can't be that huge of a problem...

 

[sutor623]

Re: Fuel line size issue.

It is the I.D. that I speak of. The 1/8" hose fits super tight. The 3/16" fits very loosely. Even after putting on some zip ties (which is the way the factory does it) they are very easy to pull off. 1/32" doesn't seem like much but trust me it makes a big difference on what I am fooling with. And I actually ordered 5/32" of the net, but it is tygon. (Green, translucent, and made specially for R.C. boats/cars/choppers)