"My problem it's that my engine not allow me to accelerate normally."
Sven, the usual cause of poor acceleration is lack of fuel. (Although at current prices that may be a good thing!)
Assuming the problem occurs when the engine is no longer cold, some possibilities to check:
Dirty fuel filter or filters.
Dirty engine air filter element.
Weak fuel pump - insufficient fuel pressure.
Dirty carburetor - dirt in the bowl so the float cannot move sufficiently to open the fuel inlet valve.
Another possibility is that the ignition timing is incorrect - badly retarded.
If the problem occurs only when the engine is cold, the carburetor's choke is not working - stuck open. Or the engine's thermostat is stuck open so the engine is running below its 80 degree C operating temperature.
Of, course if someone has recently worked on this motor he may have done something to cause the problem. Or, if the problem occurred suddenly, it could be due to bad fuel.
Finally, Haynes manuals attempt to describe too many models, in my opinion, and so do a poor job when an owner needs information on HIS car!
I hope these suggestions help you find and fix the problem.
Tom I