CS-2511 Compression?

[MAWoodsman]

Is there also another Schrader valve in the bottom of your adapter?

The adapter is about an inch long and just reduces the main line down to fit the plug hole.

 

[huskihl]

The adapter is about an inch long and just reduces the main line down to fit the plug hole.

That’s why you have a low compression reading. If the adapter doesn’t have a Schrader valve in the bottom of it, the adapter volume is added in to your combustion chamber. You will always get a low reading using that adapter, especially on a 2511 that has a small piston and combustion chamber anyway.

 

[Chevboy0167]

This...... all bullsh!t aside......

https://www.ebay.com/itm/185806939630
https://www.stens.com/search?keywords=752-311

 

[Chevboy0167]

And will it run with less than 100psi???? No.... but maybe! I worked on an Echo trimmer one time that ran "decent" with 85psi on the dot. Never say never!

 

[MAWoodsman]

This...... all bullsh!t aside......

https://www.ebay.com/itm/185806939630
https://www.stens.com/search?keywords=752-311

This says it fit 14/18mm plugs. The 2511 threads are about 9.8mm.

 

[Chevboy0167]

Well sh!t... I have been slacking as of late! Guess my mind is still on refurbishing older Cobra CB radios still..... damn the bad luck!

Anyways.... perhaps an adapter? I do believe I have that size in my Mityvac gauge kit... hmmmmm... I best look.

All I can say is the gauge I linked to is for small engine. I have 1.... for now... might grab another for backup sake. Short hose, light spring Schrader valve in the adapter tip and the like.

 

[MAWoodsman]

Well sh!t... I have been slacking as of late! Guess my mind is still on refurbishing older Cobra CB radios still..... damn the bad luck!

Anyways.... perhaps an adapter? I do believe I have that size in my Mityvac gauge kit... hmmmmm... I best look.

All I can say is the gauge I linked to is for small engine. I have 1.... for now... might grab another for backup sake. Short hose, light spring Schrader valve in the adapter tip and the like.

I thought using an adapter was bad because it increases the compression chamber, resulting in low compression readings on the gauge.

 

[Chevboy0167]

Well.... they sell it! LOL

https://www.ebay.com/itm/1756728947...nh6J1uIslLs+nTkrbhz6o2uMHw==|tkp:BFBMxI2uru5h

 

[huskihl]

Echo 91151 ^ has a schraeder valve in it, which is what’s required

 

[MAWoodsman]

Echo 91151 ^ has a schraeder valve in it, which is what’s required

30$ for a 1inch adapter...bastards...

 

[mountainlake]

If the saw runs good and cuts good don't worry what the compression is. Steve

 

[MAWoodsman]

I got the Stens gauge in. On my 4910, which it fits without an adapter its hitting 190psi. Thats 60 more than the other gauge i was using on my 4910/2511.
If i figure the first gauge was 40-60psi off on my 2511, it would be around 140-150psi.

Thx all for your feedback and guidance on this.

 

[numnutz6383]

I got the Stens gauge in. On my 4910, which it fits without an adapter its hitting 190psi. Thats 60 more than the other gauge i was using on my 4910/2511.
If i figure the first gauge was 40-60psi off on my 2511, it would be around 140-150psi.

Thx all for your feedback and guidance on this.

I got this gauge based on budget and reading a number of threads on here. Yet to use it though.

 

[MAWoodsman]

I got this gauge based on budget and reading a number of threads on here. Yet to use it though.

Got a link?

 

[numnutz6383]

I got it for $23, apparently things have changed at $52. Search the forum for the make and model to determine if this is what you want.
Actron CP7828A Professional Compression Tester Kit with 10mm, 12mm, 14mm, 14mm Long Reach, and 18mm Adapters, Black https://a.co/d/4WlVHuc

 

[paperclips43@]

I got the Stens gauge in. On my 4910, which it fits without an adapter its hitting 190psi. Thats 60 more than the other gauge i was using on my 4910/2511.
If i figure the first gauge was 40-60psi off on my 2511, it would be around 140-150psi.

Thx all for your feedback and guidance on this.

Are you saying you got the right compression tester for small engine chainsaws and you tested it on your 4910? Your logic seems sound enough that the 2511t would be around 60 more psi but I’m just wondering why you didn’t test it..
I also got 90/95 psi on my 2511t using my mityvac comp tester with adapters I bought claiming to be for small 2strokes but the saw runs great for the most part so it’s likely 150psi ish, if had had the right valve/adapter set up, which makes sense. I bought it used and it had some scoring that was visible from the exhaust port when I took the muffler off to gut it.
It’s a bit finicky but has been a great first saw although I’m now getting ready to buy a new short block to replace it and try my hand at my first port on the old one.

 

[Chevboy0167]

The key here is you are looking for the SHORTEST distance from gauge to threaded fitting for the cylinder. Cylinder volume is small for a saw or similar outdoor power equip. Plus the low pop off pressure of the schrader.

If you have a long hose or extension, that adds extra volume to fill.



https://schrader-pacific.com/wp-content/uploads/Valve-Core.pdf

 

[huskihl]

The longer hose takes more pulls to get to the max reading but that max reading will be the same whether it’s a long hose or a short one. In order get an accurate compression reading you need a Schrader valve right down inside the adapter that threads into the combustion chamber.

 

[Vintage Engine Repairs]

The longer hose takes more pulls to get to the max reading but that max reading will be the same whether it’s a long hose or a short one. In order get an accurate compression reading you need a Schrader valve right down inside the adapter that threads into the combustion chamber.

Spot on, and one that is designed for small engines, as they have much less spring pressure than automotive shrader valves

 

[pro94lt]

I checked 2 of my 2511's with an adapter with no valve and they both only showed 60psi lol