[gvarney13]

Good evening,

I am in need of some guidance. I just purchased a new bass boat(new to me). It has a 1984 150 Mariner V-6. It starts up great, but when idling it jumps from anywhere around 800 rpm's to 1100 rpm's. I just ordered a book on it. Where should I start fixing these issues? Thanks in advance.

[tashasdaddy]

check you spark on all cylinders, and compression.

[Chris1956]

Guy, Is it just the tach that jumps, or does the motor speed up and down? If it si just the tack check the input signal at the tach. if it is the motor, check the spark plugs for color and water. if they are fouled or shiny clean, you have a fouling problem or a water intrusion problem, respectively

[gvarney13]

Thanks Chris1956

I pulled the plugs and they were black on all 6 cylinders. They are brand new so I cleaned them up and put them back in and there was no difference in the idle.

[Chris1956]

Guy, Does it now idle properly, or still surge? If it still surges, I would put a timing light on it and see if you have consistant spark on all six.

[j_martin]

Guy, if you want help, answer the questions.