Black or Blue Fuel Diaphragm in 026 Stihl?

[max2cam]

Old Stihl 026 with WT-194 Walbro carb and I'm rebuilding the carb. Rebuild kit has blue plastic and rubbery black fuel metering diaphragms, but old one in carb is tan Teflon type. Should I use the blue one or the black one? Or try to find a new tan one online? I run non-ethanol premium gas at 50:1 mix. I searched for the answer but nothing turned up for an 026. Thank you!

 

[stihl86]

Black one will pump more fuel. The blue one will outlast the black one.
Or so they say.
Both will work and you’ll never notice any difference

 

[max2cam]

Black one will pump more fuel. The blue one will outlast the black one.
Or so they say.
Both will work and you’ll never notice any difference

If there's no working difference between them maybe I'll use the one that lasts longer -- so they say. Plus it is a pretty blue color and the old girl (1992) might like that. Thanks!

 

[heimannm]

 

[max2cam]

View attachment 795276

Thanks for the useful chart!
Lat it, the Teflon diaphragm would seem to be the best choice for a chainsaw. But this OEM Walbro rebuild kit K10-WAT doesn't have the Teflon one, only the rubber and acetate ones.

WAIT! Actually it does have a Teflon one, but that one doesn't have the little flapper valves on it, only totally open cutouts! What's the deal with that? Is the part defective or does some applications call for a pump diaphragm without the flap thingies? That seems very weird to an amateur like myself, but some of you experts must know the reason for it.

 

[HarleyT]

I always get the k20 kit, it has both size needles, and a big variety. This one has 3 teflons!!

 

[HarleyT]

This is your kit? You will have to use the blue one if it is.

 

[max2cam]

View attachment 795585 This is your kit? You will have to use the blue one if it is.

Yes, my kit is the second K-10 one. Next time I'll know to get the K-20 kit. Funny there's two different kits. And I did use the blue diaphragm. Reassembled it today and it started fine. Carb needs adjusting though. Thanks!

 

[HarleyT]

The thing to watch is the smaller moon shaped gaskets and diaphrams, the k20 has a butterfly shape. But most carbs use neither.