[billcallahan3089]

I have a Yamaha F100 2000 4 stroke. When accelerating it sputters, otherwise it runs smooth. Have check the vacuum line going to the vacuum advance and there is no vacuum. Cannot find where the other end is connected without removing components. Could the hose be pinched or disconnected?

[bamafan]

The advance is controlled by the computer. It utilizes a throttle position sensor. The sensor tells the computer where to set the advance.

[rodbolt]

hello find a service manual. then check the accelerator pump circuits. it does have a provision to enrich the fuel mix on rapid throttle opening. good luck and keep posting