Igneous Rock is formed when a magma cools underground and crystallizes or when it erupts unto the surface of the ground, cools and crystallizes. Magma that erupts onto the surface is called lava. When magma cools slowly underground the crystals are large enough to see.
Readings for compression tests usually vary between 175 to 250 PSI (Pounds per Square Inch). A higher reading generally indicates better engine performance; however you should check your vehicle manual to find out what the ideal reading should be for your vehicle.
On a 4 stroke, compression could be lost through the intake or exhaust valves, piston rings, or head gasket. On a 2 stroke, the piston ring(s) or the head gasket. As you can see, a compression test will simply tell you whether you have adequate compression or not, it does not indicate where the problem lies.To pinpoint the problem on a 4 stroke, a leak down test will have to be performed. JOIN OUR NEWSLETTER.n a 2 stroke, the piston ring(s) or the head gasket. As you can see, a compression test will simply tell you whether you have adequate compression or not, it does not indicate where the problem lies. To pinpoint the problem on a 4 stroke, a leak down test will have to be performed. JOIN OUR NEWSLETTER.