Problem with RPM

[Primoz Rojc]

Hello guys, I have a problem with the carburettor or negative pressure, otherwise I don't reach more than 4500 RPM, or at these RPM it happens as if there is too much or not enough fuel, because the engine starts to squeak, and when the gas is lowered, there are explosions in the exhaust. I only have one connected vacuum from the valve cover. Is it possible that I should also have connected the vacuum that is in the front, lower right?
thanks for the answers.
169229

[Gordon Levy]

Cap it