HELP! I'm stumped...

[trooney]

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?

 

[Squareground3691]

Any idea what ur squish band is at , ?

 

[trooney]

Any idea what ur squish band is at , ?

No, but it's stock KS with an Oem gaskey

 

[trooney]

Any idea what ur squish band is at , ?

Steve is sending me a Mahle cylinder that I'll put on and try. Really weird...

 

[EFSM]

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]

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
.

 

[trooney]

Got it to spit once or twice but that's it

 

[Al Smith]

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]

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]

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.

 

[jacktheripper]

I’ve had strange results lately with compression on both a 272 and an 064. Turned out with both of them that the ring gap was too big. On new Caber rings. Check your ring gap. New rings fixed both of mine.

 

[Mastermind]

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.

 

[cus_deluxe]

ring end gap? cylinder wall glazed or something? just spitballin. i had a 181 cylinder with a groove a couple mm wide all the way to the top of the cylinder wall and it ran fine.

 

[trooney]

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...

 

[cus_deluxe]

.004” per bore inch i think? so .010-.011 is what id shoot for

 

[Al Smith]

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]

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

 

[Outback]

Pour some gas in its carb hole?

 

[Stump Shot]

Steve is sending me a Mahle cylinder that I'll put on and try. Really weird...

Check your front porch, it should be there.

 

[redline4]

If your pulling the jug back off, I'd be checking it for out of round or taper as well. Can probably use the ring at various points down the bore to get a rough measurement.