Funny one of my clone saws is pushing 190 lol. my old husqvarna 61 is a little under 150.
Two-Stroke Oils: All the Same?
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Lots of variables for compression ranges....
My craftsman S145 is pushing 190 and the performance for a stock saw is pretty good compared to other box store wonders.
I did a fuel line service on an old Echo SRM225 with 82# compression.... it still started and ran "decent"... LOL. The owner was tickled pink that his $35 unit investment runs. Still running to this day.....
Absolutely Sean , testing variables with or without a Schrader valve , type of test conditions etc .
I was thinking more along the lines of combustion chamber size, carbon build up, ring wear ect. But yes. Test equipment and testing conditions defintaly make a difference too.
Well that's quite correct . That is why i initially mentioned stock saws , where the variables are less with higher squish area & lower relative compression ratios . I was also assuming engines in "good state of repair " , apples to apples as much as possible . Secondarily is the accuracy of the testing equipment & the testing protocols as mentioned . I have witnessed testing results all over the board , with very inaccurate readings due to improper testing equipment . However , the contributing factors you have highlighted most definately affect the testing readings accordingly lol.
Yes sir cold readings
Husky77
ArboristSite Operative
I got a husqvarna 550xp starts great runs great and cuts perfect, like a new saw.... yet after testing with three gauges its showing cold, wait for it....
115psi. Work that out because I'm mystified, piston, ring and cylinder all perfect.
115psi. Work that out because I'm mystified, piston, ring and cylinder all perfect.
If you don't have a schrader valve or too long of a hose , etc readings will be inconsistant . Also i run my saw 1st to warm the bore & piston & lube the rings prior to 5 good pulls with tester . I have seen + or - 5 # difference routinely with various guages . I have seen many saws hardly want to start at 100 # or less . I would assume your saw is probably much higher that 115 # .
The Shooters Apprentice
Addicted to ArboristSite
What are you guys running for compression testers? I have a harbor freight one and a Amazon one, burn with about 1’ hoses and they always read way lower then that I would like to see.
This... but of course it's no longer made I think.... Got mine of eBay 3 yrs ago.
Found the equivalent to mine but damn that a premium price! Think I only paid $38.00 at the time...
https://www.ebay.com/itm/2931247571...KKvJMpa2lIounTv1nocQJ+Ko8=|tkp:Bk9SR5DM84yCYQ
https://www.ebay.com/itm/2931247571...KKvJMpa2lIounTv1nocQJ+Ko8=|tkp:Bk9SR5DM84yCYQ
I have a Snap on unit for my Snowmobiles & Dirt bikes , also a Mityvac for my saws & trimmers & blowers .
I too have the Mityvac kit for automotive.
For Automobile / Diesel application I have a Lang Industries tester . It is a multi tester for compression / vacuum & refrigeration & cooling testing requirements . The Mityvac though is a very fine unit for small engine usage with a great price point .
Snap on, gas and diesel compression testers. Well I have 2 or 3 sets of the gas testers. Someone borrows it, I forget who has it and buy a new set then the old set come back. No one gets to use my diesel set.
I believe the 550 uses the smaller spark plug? If so, you’ll have an adapter that screws onto the end of your compression tester to fit the smaller spark plug hole. Most of these adapters don’t have a Schrader valve in the end of it and you will get low readings with them
Tomos770
ArboristSite Guru
Yes.....it has CMR6H sparkplug...
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