Testing a compression release?

[benmyers]

Ok, I searched and found some stuff, but couldn't find a set way or proper way to test a compression release. I have a Husky 362 that tested 90 psi, but the ring gap is good on both the old ring and with the new one installed. Cylinder and piston look very good, no scoring on either. It runs good but lack a little power. I was thinking to spray soapy water around the compression release while its idling? That's the best way I could think to check it, and couldn't see it hurting anything. Or should I just spend the $10 and get one since I don't know of anything else it could be? Any ideas?

The tester, by the way, tested 160 on my 026, 155 on my 044, etc, etc. I believe it is testing correctly. Any help appreciated!

Thanks
Ben

 

[matt9923]

Just plug it with a bolt. See if that helps. Let the new rings set.

 

[mtngun]

Or should I just spend the $10 and get one since I don't know of anything else it could be?

Or just swap the release with one from another saw.

There is also such a thing as a plug for the compression release hole. I'm not sure where you get them, though. I have one laying around that originally came installed on an Oly 980.

 

[matt9923]

Does you tester have a schrader valve?

 

[lone wolf]

soapy water will find any leak

 

[benmyers]

Schrader Valve

I am not entirely sure what a schrader valve is, but from what I've read here, it seems like it's a one-way valve that lets the pressure "build"? It does have something like that that looks something like a small valve stem like you'd find on a tire.

 

[sonorachainsaw]

whats a shrader valve

 

[benmyers]

Google it. I just did some quick research, and yes, my tester for sure has one. Do some not?

 

[mtngun]

benmyers, since you stated your other saws show normal compression, it seems likely that the compression gage is working correctly.

It's worth ruling out the compression release, but I'm guessing the saw has a low compression ratio, either because of excess squish or just a big combustion dome.

 

[sonorachainsaw]

im sure that if it holds pressure it has one two saw shops told me that you pull till you cant get no more pressure

 

[biggenius29]

Ok, I searched and found some stuff, but couldn't find a set way or proper way to test a compression release. I have a Husky 362 that tested 90 psi, but the ring gap is good on both the old ring and with the new one installed. Cylinder and piston look very good, no scoring on either. It runs good but lack a little power. I was thinking to spray soapy water around the compression release while its idling? That's the best way I could think to check it, and couldn't see it hurting anything. Or should I just spend the $10 and get one since I don't know of anything else it could be? Any ideas?

The tester, by the way, tested 160 on my 026, 155 on my 044, etc, etc. I believe it is testing correctly. Any help appreciated!

Thanks
Ben

Take the compression release out and put a bolt in it. Why do you need it?

 

[benmyers]

Take the compression release out and put a bolt in it. Why do you need it?

I certainly don't! I would probably not use it anyway. I assume you have removed/plugged yours in the past? Is it necessary to seal with some type of high temp RTV or somthing or just bolt in with lock washer or loctite?

 

[scotclayshooter]

I doubt it would run with only 90psi compression.

I have heard of the comp releases having carbon build up on the seats and not close.

 

[oldsaw]

As was said, swap it with another saw, and try the suspect on in the other saw. That will nail that issue quickly and without leaving the shop. Never saw much of a point of one on a small saw, but I guess they save wear on the recoil.

 

[mtngun]

Is it necessary to seal with some type of high temp RTV or somthing or just bolt in with lock washer or loctite?

A special plug that has the same threads as the release valve. A dealer might have them, or not. Might as well buy a new valve since they are only $10.

If you have another saw with a release valve, swap it, otherwise try a new valve. Please let us know what you learn because I'm curious. I'm betting the valve is OK, compression ratio not so OK.

 

[TommySaw]

whats a shrader valve

a tire valve is a schrader valve

 

[benmyers]

Ok, got it up and going. The release wasn't sealing right apparently. I ended up removing it, cleaning it up good, and putting it on. Saw has 150 pounds compression now, and an extra release on the way. Thanks guys.

 

[scotclayshooter]

Great news!