iDRY Vacuum Kilns

Sponsors:

372xp

Started by Knute, March 09, 2010, 08:00:44 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Knute

Can you tell me what to expect the compression to be on a new or nearly new 372xp

Rocky_J

In 30 years I've never put a compression tester on a chainsaw, but I'll take a guess and say at least 150 once the rings are seated. That usually takes 4-5 tanks of fuel (working, not idling).

Knute

Thanks. I see used saws advertised and often they will list the compression. Without knowing what the compression is on a newer saw, I don't know if it is good or not.

flushcut

  It is around 150psi and from what I've  hear.  They tell you that is has compression so that way you know that it is  not burned up. smiley_thumbsup
Husquvarna Chainsaws

joe_indi

With the switch off and the decompression valve pushed in, pull on the starter smartly.
If the decompression valve pops up, you have decent compression.
Simple eh?

Cut4fun

I wouldnt really go by de-comp pushed in and it pops open when pulled through as   good to go.  365 with 115psi pops the de-comp just fine and it was worn out. This was with switch on and it burped.

HolmenTree

On the 576XP AT s I have the button pops out when running.
Willard
Making a living with a saw since age 16.

Rocky_J

Quote from: HolmenTree on March 20, 2010, 10:51:43 AM
On the 576XP AT s I have the button pops out when running.
Willard
Isn't that what it's supposed to do?  ::)

:-\

JohnG28

I thought the same, aren't they supposed to pop back once it starts?
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

HolmenTree

Quote from: Rocky_J on March 20, 2010, 11:09:24 AM
Quote from: HolmenTree on March 20, 2010, 10:51:43 AM
On the 576XP AT s I have the button pops out when running.
Willard
Isn't that what it's supposed to do?  ::)

:-\
Easy boys, I was just relating to Joe's earlier post. Joe said with the ignition switch off crank engine over quickly and valve should pop up.
My 090 AV decomp pops up automatically, its spring loaded :D
Willard.
Making a living with a saw since age 16.

HolmenTree

Quote from: joe_indi on March 20, 2010, 08:47:36 AM
With the switch off and the decompression valve pushed in, pull on the starter smartly.
If the decompression valve pops up, you have decent compression.
Simple eh?
Thats very true Joe, my 372XP has a "loose" decomp valve too. It pops out on its own too without the engine running.
My 576s have a rubber grommet sealing the valve button in the top covers hole, so I guess thats why its a little stiffer to pop out.
There now I can rest my case :D
Willard.
Making a living with a saw since age 16.

JohnG28

I dont run a larger Husky with a decomp, just my Stihl has it, and I hadnt noticed it popping when cranking, only once it burps or turns over, thats what I meant. I wasnt trying to say that you guys werent right, just hadnt seen this before.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

Cut4fun

Quote from: JohnG28 on March 21, 2010, 10:06:16 AM
I hadnt noticed it popping when cranking, only once it burps or turns over, thats what I meant.

You got me thinking, I dont think any of mine pop the de-comp with switch off. I will have to go check and get back. I got them from 130-150-160-170-180 and up.

Rocky_J

If you have a saw that will pop the decomp button with the switch turned off, then you need a new decomp.  ::)

HolmenTree

Quote from: Rocky_J on March 21, 2010, 01:05:39 PM
If you have a saw that will pop the decomp button with the switch turned off, then you need a new decomp.  ::)
No as Joe says "switch off and crank smartly" :D ::)
Willard.
Making a living with a saw since age 16.

JohnG28

Im not trying to argue or say your not correct, but on the Stihl Ive cranked it accidentally without turning on the the switch to run position, and the decomp stayed down until I switched to run and it turned over.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

Cut4fun

Quote from: joe_indi on March 20, 2010, 08:47:36 AM
With the switch off and the decompression valve pushed in, pull on the starter smartly.
If the decompression valve pops up, you have decent compression.
Simple eh?

I just tested this theory. Switch off and on 2 saws that have 180psi and another with 190+psi. de-comps did not pop off no matter how smartly I pulled them over. 

joe_indi

The keyword here is smartly.
What I mean is more force that the usual starting force.
Ground start position is not good.
Between the thighs is better.
Okay there is another thing .
This test was what I do for Stihls.
The Husky de-compression valve has more air through flow than that on a Stihl.
Could this be the reason why its not working?

Cut4fun

I was doing Huskys. I will go try on my Stihls now too. Yes I was pulling VERY SMARTLY  ;D, alot harder as if I was checking compression.

JohnG28

That could be why we're not getting same results.  I almost always use the thigh position, and I pull pretty hard, but I dont yank on it in an attempt to pull the cord right out, dont need any avoidable repairs.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

Cut4fun

2 Stihl 084  didnt pop either , one stock psi, one with monster psi.  Yes I pulled very smartly.

066 dont have a de-comp and no longer have a 361 to test.


But I do have extra 361 and 066 de-comps I could put in my high compression Huskys to test that theory too.   ;)

JohnG28

Cut4fun, the saw I speak of is a 361, just getting nice and broke in, high compression...doesnt pop till running
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

Rocky_J

I would say that Joe Indi has a couple bad compression release buttons. The supposed technique he suggested to test compression does not work, or at least it should not work. Maybe he's using inferior mix oil and the compression release valves are plugged up with carbon?

Cut4fun

Quote from: JohnG28 on March 21, 2010, 04:40:15 PM
Cut4fun, the saw I speak of is a 361, just getting nice and broke in, high compression...doesnt pop till running

I'm just testing Joe's theory's is all.  I dont think that way he suggested works.

JohnG28

Is there any chance that the placement of Husky decomp valves could have anything to do with it, as the ones I can think of come out the side of the cylinder, as opposed to Stihls placed on the top?  Just thinking of possible scenarios that could be a variable here with the different results we seem to be getting.  I doubt that this would be the case, but just a thought.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

Thank You Sponsors!