Recent content by SteveSr

I just ordered both of the 1mm CS rings from here: https://www.theoringstore.com/store/index.php?main_page=index&cPath=368_65 I also ordered in V75 (Viton compound). These are 75 durometer which is fairly close to the normal 70 for Buna-N.

@Vintage Engine Repairs Would you mind sharing your o-ring source? Either through Amazon or direct.

Just for grins you might want to take a sample from each lot and soak them in petrol for a month or so and see if they change size or stiffness.

Those are Zama part numbers not Stihl. I didn't think that Zama was a German company. Great detective work! Unfortunately the 2.3 x 0.8 is smaller than standard sizes. The smallest that I have found is the 3.0 x 1.0. I think that I have some of the smallest size directly from Stihl...

I have been looking at several manufacturers. One of them, Marco Rubber, says that regular nitrile/buna-n is NOT recommended for fuel applications! Huh? Well apparently there are several varieties of Buna-n. One is hydrogenated which is rated for fuel use. I doubt that Ebay / Amazon can tell you...

I just disassembled the pump on a C1Q-S174 carb off of a Stihl 4-mix. Here are the relevant dimensions of the piston: Diameter = 0.215" (5.46mm) Ring groove diameter = 0.144" (3.66mm) Ring groove height = .044" (1.12mm) Based on these measurements it looks like an M3.5x1 o-ring is correct for...

Well, like I was saying, this is the standard imperial chart and cross section doesn't go below .040" A similar metric chart doesn't go below 1mm (.039") cross section but at least there are more I.D. options. So it would appear that these are custom unless someone knows another rock to look...

As in buy the Zama part numbers or stock to resell?

Do you know if any of these tiny o-rings are standard sizes or if they are custom made? This particular one looks like it is close to M3x1. Tom's M2.3x.8 is actually close to 3/32" x 1/32" imperial but the imperial cross sections for standard sizes don't go down to 1/32" (0.8mm) so am...

@Vintage Engine Repairs Just curious where you got your o-ring dimensions from? Did you measure samples or find actual documentation for the sizes? I think that your m2.3x0.8 might actually be 3/32" x 1/32" imperial (.094" x .031"). I am getting ready to order some wher the shipping is likely...

Well, I did a little research and I think I have a plausible explanation. FCW is Freudenberg and the attached datasheet shows seal color corresponding to seal material type. The blue is regular nitrile whereas the brown is a fluoropolymer. The fluoropolymer holds up much better to fuel and...

I think that you got this backwards. Take a closer look at the photos. These are the "hard" OEM seals that came from the factory.

Hello, Currently working on rebuilding an MS251. I have 2 engine assemblies and am going to make one good one. I noticed that the oil seals appear to be a different color from the FW and PTO side. This makes me wonder if they are different materials. The PTO side is brown while the FW side is...

I like that shopping basket idea for holding parts while spraying!

This looks to be something new. The old Gunk Engine Brite was just kerosene in a spray can!