Originally Posted by Oli
After cleaning the carbon from the pistons, installing new rings, and cleaning the cylinders; compression for both units is still 90 psi. Once again, no sign of scoring on the pistons or cylinders. Both units fire and run when gas is dribbled into the carb port.
Take a tea spoon of 2 cycle oil and pour it into the cyclinder, do not put the spark plug back in, cycle the piston a few times to get the oil around the rings and on the cylinder. It's messy, cover it with a rag or something. Now check your compression, if it hasn't come up....
Well, it's a judgement call if you want to spend more money and time on them. You could buy a new one for what the parts could add up to....