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trooney

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This has been the most frustrating build I think I've ever done. It's a Husky 262. This is the problem. It's got low compression. New meteor piston, p&v fine, flywheel key intact, carb is holding pressure. This is the second piston I've put in it because I thought there might be something wrong with the first. That was a new piston too. I can't get it to go over 110 psi. It's got a little chunk taken out above the exhaust port, but I smoothed that out. Would that make it lose compression? What would make a saw have low compression when the basics are good?
 

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It's got a little chunk taken out above the exhaust port, but I smoothed that out. Would that make it lose compression?
Yes, that will reduce the compression. Does it have a base gasket in? The next question is what compression gauge are you using? One with the valve at the threaded end of the hose?
 

trooney

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Yes, that will reduce the compression. Does it have a base gasket in? The next question is what compression gauge are you using? One with the valve at the threaded end of the hose?
Has the gasket, and yes. It's the one I've been using for a long time. It's pretty accurate
.
 

Al Smith

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Two things .One it takes a bit of run time to get the rings fully seated .Two,according to Stihl which should apply to just about any brand is anything over 100 PSI should be good to go .
 

trooney

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Two things .One it takes a bit of run time to get the rings fully seated .Two,according to Stihl which should apply to just about any brand is anything over 100 PSI should be good to go .
Well, I can certainly say that for a new piston and everything checking out alright 110 is really low. If it was a really used piston then maybe. Usually around 150. So somethings wrong, just can't figure out what. You've got to get the saw to run to get some run time on it...
 

Outback

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Does it feel like 110? If so try the tester on another saw. I've had the shrader valves get sticky/dirty. When that is the case they read around 100-110. If that happens I'll wash it in mix gas and put it back in and it works.

You could pour a little oil in the cylinder via the plug hole to see if it is poor ring seal. With oil the compression should go up. Could be enough to get it started.
 

trooney

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I'm gonna suggest a vacuum\pressure test Tom. If this saw ain't got a strong impulse signal, it ain't gonna run. That divot at the port will make cranking compression lower than normal....but once running shouldn't be a issue.
Yeah, I did a p&v on it and it was fine. Maybe the ring? How much gap should I have. I've got the feeling it's with the cylinder somewhere. It's a head scratcher for sure...
 

Al Smith

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I thought of another problem that could cause no start .I experanced this very same thing on first a 2100 Husky and I think recently on 281 .The damned fuel lines collapsed pinching off the fuel .Those designs of fuel lines are limber as a wet noodle .Then because of the time period before ethanol gas the rubber might not have been formulated for it .100 psi static should be enough to get it started I would certainly think .
 

Mastermind

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Yeah, I did a p&v on it and it was fine. Maybe the ring? How much gap should I have. I've got the feeling it's with the cylinder somewhere. It's a head scratcher for sure...
Weird one for sure my friend. Like was mentioned. About .010 - .011
 
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