You are in the right place, Gerson, it is a Powertorque-doesn't-start-easily issue.
The usual way to check whether the decompressor is keeping your engine from starting, is to remove it. Just unscrew it from the cylinder head, temporarily put an ordinary spark plug in the threaded hole, and block the hose that leads to the decompressor with a screw of the right size. Then try to start the engine. Of course you'll have to pull a lot harder than usual. If it still doesn't start the problem was not primarily with the decompressor (though it still might have problems).
How does the engine run once it starts? If it has full power and responds well to speed changes, you have a starting problem rather than a fueling problem. A starting problem without a fueling problem is most likely to be that your primer isn't working, and you may be able to see if that is the case by the way it feels when you push the bulb. You could also see if it starts easily when you prime it with a spoonful of fuel through the spark plug hole. If your primer feels right, and fuel through the spark plug hole doesn't help, and since your spark is OK, the next question is whether your compression feels pretty strong with the decompressor removed. Because you aren't used to feeling it without the decompressor this might be unclear. The next step then would be to remove the muffler and have a look at the side of the piston and the piston rings, through the exhaust port. If the rings are stuck and/or you can see rough stripes/gouges running up the side of the piston, that will be the problem. Post a picture of what you see through the port, and we can comment on whether it looks good or bad.
