076 and 075 compression release sealing ring

[NathanInAdelaide]

Hi all, i am interested in whether someone with 076 experience can gove me an idea of the compression leak due to a poor or non existent sealing ring. Have a couple at 140s psi and bore piston etc looks ok. The sealing rings are a pain to get in australia as far as i can tell so want to know if that is the likely cause? Or something else? If i cant source the sealing ring is there another option? Thread sealing somehow?
Thanks.

Nathan

 

[alexcagle]

Do you hear it leak when you roll it over slowly by hand?

 

[alexcagle]

I have in a pinch before; used a steel washer before -that has the correct inner diameter and thickness, then ground it down on the O.D. by using a nail as a spindle and held at an angle to a bench grinder wheel until enough material comes off to make it fit. Then hand file down the rough edges.
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They are available from Stihl, though they may be on backorder for a while.

 

[NathanInAdelaide]

Hi Alex. Can't really hear when rolling over by jand. Have tried to grind down a couple of steel ones i have here but keep snapping them as my grinder is pretty coarse. May have to set up a linishing belt.

Just for the record... what is the original thickess and material?

 

[alexcagle]

About the thickness of the washer in 80% of all modern stihl starters.
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If you grind the washer lightly at an angle, the washer will spin with the rotation of the grinder and wear down uniformly. You'll want to flip it every now and then to balance the wear out. Be careful though, it will be hot!

 

[NathanInAdelaide]

Thanks again Alex. Will set up the linishing belt and try again

 

[smokey7]

I use copper brake caliper washers. Available at any parts store in many sizes

 

[alexcagle]

I use copper brake caliper washers. Available at any parts store in many sizes

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Do they really make them that small?
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They are about the size of the footprint of the end of a small fuel hose.

 

[William Balaska]

Just buy it, it's a $2 dollar part. You could epoxy it solid ss well.

 

[smokey7]

Yes a good parts house has the crush washers in a big bin

 

[William Balaska]

Incredibly, if you forget to put it in the saw won't run barely.

 

[alexcagle]

Uhhhh....
Didn't you not just do a double negative?