Are Stihl Flippy Caps Supposed to Squeak and Leak?

[chipper1]

 

[PapaWhitebeard]

According to the Stihl IPL for my MS361, 25x3.5mm (Stihl part number for the o-ring alone is 9645 948 7734).

Lots of o-rings with those dimensions on ebay.

FYI the 25mm is ID (if you're looking for o-rings they usually want either ID or OD or both) "Inner Diameter" and "Outer Diameter" ID / OD

Best

 

[Chevboy0167]

Funny thing on the Husqy fuel cap that came on my brand new 562, I noticed 2 threads stripped off. Mind you, this saw never had been fueled except possibly from factory run test? It sure never smelled like it tho. 2021 model year by the way.

$7 for a new one and I have the original as a backup cuz it never leaked. Chock it up to factory defect maybe? I dunno....

 

[HansFranz]

FYI the 25mm is ID

Uh-oh...

 

[slowcar281]

Caterpillar o ring part number 4j-5267 works great for these caps. Used them many times over the years.

 

[RedneckChainsawRepair]

Here I will make this easy on ya. Because we already have a whole thread under featured tab in my group on which orings to use for everything basically made in saws and what fits.

Large and small stihl flippy oring sizes and where to order right on it.

 

[GMB74]

So, should be looking for 25od x 32id x 3.5cs o-rings?

 

[RedneckChainsawRepair]

So, should be looking for 25od x 32id x 3.5cs o-rings?

Dont know where you come up with that.

My pic above shows what you need. If large right on bag. 25x3.5 orings go by ID then thickness like shown.

 

[HansFranz]

So, should be looking for 25od x 32id

Not sure how that's possible in this dimension of the spacetime continuum

 

[GMB74]

Sorry, hadn't finished my first cup of coffee this morning.
Edited and corrected.

 

[Chevboy0167]

I got these used o-rings from Nasa... Should I use them?




If ya know... ya know......

 

[HansFranz]

 

[PapaWhitebeard]

I got these used o-rings from Nasa... Should I use them?


View attachment 1212850

If ya know... ya know......

NASA o-rings

"Made from unobtanium and subsidized with federal grant money these o-rings will hold fast even after breaking the space-time continuum"

in the meantime thank goodness guys like @RedneckChainsawRepair have big 'ole bags of o-rings

 

[RedneckChainsawRepair]

in the meantime thank goodness guys like @RedneckChainsawRepair have big 'ole bags of o-rings

Not my pic. One of the members in my group that helped put thread together.

But I do have certain orings too.

 

[PapaWhitebeard]

Not my pic. One of the members in my group that helped put thread together.

But I do have certain orings too.

woot for o-rings!

 

[WI_Hedgehog]

STIHL Flippy Caps, I have a love/hate relationship with them: I love them, but they don't treat me well. I keep them and the filler openening clean and they seem to last "forever" (I have no "recall" caps) but they do tend to blow fuel droplets out when opening a hot saw.

As the tank runs low on fuel it's full of air which is drawn in through the one-way valve by the vacuum created by fuel being pulled out of the tank. When shutting the saw off the cooling fan stops blowing air over the cylinder, and air in the fuel tank is heated by the stopped engine radiating heat into the tank causing the tank to build pressure. If the saw doesn't have time (15+ minutes) to cool, the pressure "vents" (releases/blows an air/fuel mix out) when opening the cap, and if there's any open flame it's not a good situation (to the point it's a learning module in the Wilderness Firefighting Training).

STILH screw-on caps have the same issue. One part of a solution is Husqvarna's wrench-slot which puts your hand is further from the filler cap. I suppose to be safe I could file my chain before filling the tank, eat a sandwich, drink some whisk...coffee, water the flowers, fill the oil, surf the 'net, and take a nap.

 

[PapaWhitebeard]

I suppose I could file my chain before filling the tank, eat a sandwich, drink some whisk...coffee, water the flowers, fill the oil, surf the 'net, and take a nap.

That got an actual audible LOL

The other thing we can do is just not open that fuel cap next to an open flame... (shrug)

I wouldn't *recommend* it but there is one guy who used to race motorcycles with me... chain smoker... I've seen him refill bikes with race gas... transfer fuel from one jug to a smaller container... handle gasoline with a lit cigarette in his mouth countless times...

of course *everyone* threw a tantrum every time they saw it... idk whats wrong with this guy... but once when someone came up to him yelling about fire danger he poured some gas in a cup... took the lit cigarette out of his mouth... and put it in the cup of gas.

"What happened?" you ask... the cigarette went out.

Again... I do NOT recommend smoking around your fuel tanks. I recommend AGAINST it. Against smoking, too while we're at it...

And gasoline fire danger is a real thing.

But open flames... that's the danger... if the guy *lit* a cigarette in the middle of all those gas fumes... the story would have a different ending... (shrug)

 

[capejwc]

Looked up o rings on www.oringsandmore.com. Hard to search a long time to find the 25x3.5mm o rings shown earlier in the thread. You can look them up a lot quicker if you use SKU 2535MMB70. Just order 20 at $.11 each, so even with shipping was less than $10. Lots less expensive than replacing caps that are ok, but just needs an o ring.

 

[HansFranz]

use SKU 2535MMB70. Just order 20 at $.11 each, so even with shipping was less than $10.

Are those the silicone jobbies, or just nitrile rubber?

 

[WI_Hedgehog]

Putting the SKU to the search box:

Standard Nitrile is also known as Buna-N. Excellent resistance to petroleum-based oils and fuels, water and alcohols.