Stihl R1, R3, & R5 Fuel Hose Material?

[SteveSr]

Anybody know what the difference is between the various type of Stihl fuel line is? I found a tech note (38.2011) that says the "R_" indicates the type of hose material but it doesn't say which type should be used in which application. Is some Viton and some buna?

 

[alexcagle]

Yes. The illustrated parts list, or IPL, will say what type and length you need, be it mediacat, or eservice.

They sell precut pieces, and 25 meter rolls of "R" hoses , if you prefer to save time and cut it yourself.

They are both fuel hose. Viton hose is better for instances where integrity, (resistance to breaking down and dissolving or degrading), are of utmost importance.
Viton is more resiliant and pliable, (bounces back to it's original shape, and stretches better) than R3 hose. Some applications are for fuel injection systems, and areas where lots of repeated movement (cyclic movements) and sharper bends are required. It is more resistant to kinking than R3 hose, and it's a more expensive compound of rubber.
R3 hose is buna straight hose, and is a very good fuel hose, but not as durable as viton, and can kink if bends are taken too sharply. They may kink easier near a heat source too.

 

[SteveSr]

So from this R5=Viton and R3=buna?

The last hose that I bought was R5 and it was insanely expensive at about $20 for a 1 meter piece. Does this sound about right? It did seem to be more flexible than the R3 but don't know if it is worth the extra $.

 

[alexcagle]

Wow. That's high. Did you ask if it came with a jar of Vaseline? LOL
Good question.
I think it has to do with wall thickness vs inner and outer diameter that gives it either an R3 or R5 designation..
I will ask my Stihl Master Tech teacher in VA that question and get back with you.

 

[DND 9000]

The R5 line is a nitrile type that meets EPA regulations. This line is a wet hose when the engine is running. It`s made of R5 nitrile and this is required for meeting EPA guidelines for permeation of fuel into the air.

The R3 line is used in applications where it will not be wet with fuel when the engine is running. (vent hose, impulse hose etc.)

 

[LegDeLimber]

Thanks for the information guys.
If no one objects, I'd be interested to learn about the other OEM brands of fuel line and their compositions, also.

 

[SteveSr]

The R5 line is a nitrile type that meets EPA regulations. This line is a wet hose when the engine is running. It`s made of R5 nitrile and this is required for meeting EPA guidelines for permeation of fuel into the air.

The R3 line is used in applications where it will not be wet with fuel when the engine is running. (vent hose, impulse hose etc.)

WOW! So EPA now cares about the hydrocarbons that leak through the hose. I thought it looked like the R5 hose had some sort of outer covering layer on it.

Back in the early 80's I seem to remember that Honda had motorcycle fuel hose with an outer layer to ward off attack by ozone. I remember it lasted a good long time, much longer than standard hose at the time.

A lot of the Stihl IPLs that I have list R3 hose for wet applications. I guess that R5 hadn't been invented at that time.

Someone else can correct me if I'm wrong but isn't buna and nitrile the same thing?

 

[alexcagle]

Correction; I said viton but meant nitrile hose.

 

[SteveSr]

Thanks for the update! 2 out of 3 local dealers are still using R3 for all applications. Only one actually has R5 by the foot for $6/ft! The two others have R3 for $2/ft.

Rummaging through my pile of old hose pieces I actually found a piece of *grey* hose labeled R3. The only grey hose that I know of now is R5. Does anyone know did Stihl upgrade the hose before changing the designation to R5?

 

[backhoelover]

here you go

 

[SteveSr]

here you go

Thanks for everything, especially the SVC105, as it explains the rationale for the change and t he new intended application.

A question... So now if you buy a molded fuel hose through a Stihl dealer are they in any way denoted (i.e. color) that they meet the new EPA guidelines?

 

[backhoelover]

Sure do and the only way to get it cheap is by 1000ft rolls

 

[bmwpowere36m3]

Is Stihl 0000 930 2804 (3.1mm id x 6.7mm od) still available? Have a 034AV needing an impulse line...

That or an alternative, such as NBR or silicon vacuum hose (automotive) or Echo fuel line 3x6mm (90015) or 3x7mm (90016)?

 

[alexcagle]

Yes, It shows available from Stihl. You will want to use the correct hose as it is designed to take the flexing cycles between the tank and crankcase.
By the way, this thread has been stagnant since june 2016. Cheers

 

[bmwpowere36m3]

Yes, It shows available from Stihl. You will want to use the correct hose as it is designed to take the flexing cycles between the tank and crankcase.
By the way, this thread has been stagnant since june 2016. CheersView attachment 533835

I'll have to stop by the dealer and check... doesn't seem like a common Stihl hose based on quick internet search. Wondering if it would be better to go with one of the 3.1 x 5.7 mm hoses (R3 or R5)? Seem more common and not end up having to buy a roll or get real old stock.

 

[backhoelover]

i use the echo line buy it by the box. it just as good as stihl and way way way cheaper

 

[bmwpowere36m3]

i use the echo line buy it by the box. it just as good as stihl and way way way cheaper

For impulse as well? I guess I'm questioning whether a 3x7 line is needed or a 3x6 could be used.

 

[alexcagle]

Is it Nitrile?

 

[bmwpowere36m3]

Is what nitrile? The original 034 impulse?

 

[bmwpowere36m3]

@alexcagle

Do you have access to current IPL? Could you do me a favor. I have two copies, one marked 07/2004 and the other "printed from MediaCat".

Each lists a different P/N for the impulse line (Illustration K AV system, part 15).

• "07/2004" lists: 0000 930 2804 (Hose 3,1x6,7 mm x 1 m)
• "MediaCat lists: 0000 930 2803 (Hose 3.1x5.7x1000mm)