Compression Readings And Rebuilds

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Campin' Cutter

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So the journey continues on the 288 I picked up earlier this month. Compression reading is 150 with my Echo compression tester. Not real low, but not great either.

I had the muffler off tonight and when looking in the exhaust port the piston definitely had some light vertical scoring (can see it, but can't feel it with my finger), and the same light scoring can be seen on the cylinder.

At what PSI reading do you guys typically dive into a saw and rebuild it? My understanding is that a healthy 288 should be between 160 and 180.
 
So the journey continues on the 288 I picked up earlier this month. Compression reading is 150 with my Echo compression tester. Not real low, but not great either.

I had the muffler off tonight and when looking in the exhaust port the piston definitely had some light vertical scoring (can see it, but can't feel it with my finger), and the same light scoring can be seen on the cylinder.

At what PSI reading do you guys typically dive into a saw and rebuild it? My understanding is that a healthy 288 should be between 160 and 180.
You are correct. But 150 will work OK , if you run the saw a while you can decide if its low on power or not and in need of rebuilding.
 
You are correct. But 150 will work OK , if you run the saw a while you can decide if its low on power or not anxd in need of rebuilding.
Thanks for the info! I'll take her out this weekend and cut some mesquite and see how she does.

I haven't really had a chance to cut with her yet, as the first time I tried to test her out both muffler screws went missing in under a minute! Hence why I had the muffler off the saw to begin with.

Torqued em down good and used a little high temp blue loctite,so hopefully they stay put this time.
 
150 is fully serviceable.[emoji106]

130 or below is piston kit time.

Marginal cylinder after I cleaned off the aluminum transfer:

7f8b26469f33e8873debb04e24552a6d.jpg



That’s melted piston material in the exhaust port.[emoji13]

A new OE piston kit and it pumped 150 after twenty minutes of run time.
 
150 is fully serviceable.[emoji106]

130 or below is piston kit time.

Marginal cylinder after I cleaned off the aluminum transfer:

7f8b26469f33e8873debb04e24552a6d.jpg



That’s melted piston material in the exhaust port.[emoji13]

A new OE piston kit and it pumped 150 after twenty minutes of run time.
Mine does not look anywhere near that bad so I think I'll run it and see how it does before entertaining a rebuild.
 
There are factors that go along with elevation like what is the barometric pressure. Gauges read differently as most are not calibrated. To get a average figure for elevation correction use around 3% loss for every 1,000 feet gain in elevation. This is just a average quick calculation.

So you sea level equivalent might be around 155 psi. A little better.
 
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