Accepable Saw Compression

[Duncan Tipton]

Accepable Husqvarna Saw Compression

I was checking the compression on a "new to me" mid 90'S Husky 51 (150 psi)and decided to compare it to my 2008 365 Special I bought new last year. It my horror it had a shade over 120 psi, tested cold. The saw has always run well and I have never had problems. I have used Husky oil mixed 50:1 from day one. Is this acceptable? Does anyone know what the Husky specs on compression for this saw are? Thanks for your help. Duncan

 

[litefoot]

120 sounds low. 150 sounds good. How many times did you pull on the 365? Sometimes you have to pull quite a few times to get your highest reading. Also your compression tester should have a Schrader valve tip.

 

[blsnelling]

120 PSI is way low and indicates something is definately worn or broken. Might be time for a new piston and rings. Check your ring end gap.

 

[Duncan Tipton]

I have re-checked my testing method and I get the same results. I don't thinks that is the problem because my other saws test over 150 psi with the same testing method. Does anyone out there have any more specific information on Husky's compression specs for the 365 Special? Thanks D

 

[blsnelling]

It should have 150-160 PSI.

 

[Evan]

ill give you 100 bucks for it

 

[litefoot]

I have re-checked my testing method and I get the same results. I don't thinks that is the problem because my other saws test over 150 psi with the same testing method. Does anyone out there have any more specific information on Husky's compression specs for the 365 Special? Thanks D

DT,
Pull the muffler and check the piston and cylinder for vertical scoring/scratches. Does the saw have a compression release? Make sure it's tight or replace it with a plug and test again.

 

[thomas72]

When is the last time you have run the 365? I would run it for about ten minutes then let it cool down and take a compression test. How many hours would you say it has? More than likely your piston is scored.

 

[spacemule]

The saw has always run well and I have never had problems.

That's the only test you need. Ignore the #######s who think a number is more important than real world use.

 

[spacemule]

120 PSI is way low and indicates something is definately worn or broken.

:bang:

 

[blsnelling]

Then prove me wrong. If his compression is truely only 120 PSI, then it's a matter of fact that his compression is way low.

 

[Duncan Tipton]

When is the last time you have run the 365? I would run it for about ten minutes then let it cool down and take a compression test. How many hours would you say it has? More than likely your piston is scored.

Thanks for the tip, I haven't run it in a month or so. It has 6 gallons of fuel or so thru it. I will also check the piston though the exhaust port. Checking the compression release is a good idea as well. Thanks for all the help. I'll let you know what happens D

 

[blsnelling]

120 PSI is about what you could expect with the decomp open. Don't ask how I know

 

[Norwegian Wood]

120 PSI is about what you could expect with the decomp open. Don't ask how I know

LOL

Should'nt low compression affect the saws preformance?

 

[blsnelling]

LOL

Should'nt low compression affect the saws preformance?

That's why I said "if". And who knows what the OPs perception of good performance is? Bottom line, 120 PSI is poor compression on a 365. Maybe he had the decomp open.

 

[yo2001]

I always like to see 140-150psi on a saw but I do have husky that only reads 120ish cold with new ring on it. I guess the exhuast port could be slightly too high could cause the saw to have lower compression. I might map it and see. The saw crank and runs fine so I'm not too worried about it.

 

[woodyman]

About a month ago my brother came over with his 361 and he's got abot 20 tanks on it so I said lets check the compression and compared it to my Snellerized 359 by pulling them over.I pulled his over and it felt very good then he pulled mine over and said it hasn't got alot of compression.Well I guess I had pushed in the decompression valve by mistake and didn't notice it(I NEVER USE IT).It had me going for a second

 

[Duncan Tipton]

I pulled the muffler off. The piston looks brand new with the exception of some carbon staining about 3/16 of an inch down from the top.

I also pulled the compression release and cleaned the mating surfaces of the valve. I reinstalled and checked the compression again. I got 130 psi. I have a feeling the compression release is just another pace to lose psi. I think i will just take it out and plug it.

I haven't run it up, let it cool, and tested again yet. I'm starting to think I'm just being fussy. Thanks again for your knowledge. D

 

[spacemule]

I'm starting to think I'm just being fussy. Thanks again for your knowledge. D

People who need a gauge to tell them their good running saw isn't running good are the same people that need a scale to tell them their fat ass is fat.

 

[mountainlake]

When is the last time you have run the 365? I would run it for about ten minutes then let it cool down and take a compression test. How many hours would you say it has? More than likely your piston is scored.

Right, if it's sat around quite a while it will show way low. Steve