1984 150 Mariner V6 Idle Issues

[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]

Re: 1984 150 Mariner V6 Help

Re: 1984 150 Mariner V6 Help

check you spark on all cylinders, and compression.

 

[Chris1956]

Re: 1984 150 Mariner V6 Help

Re: 1984 150 Mariner V6 Help

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]

Re: 1984 150 Mariner V6 Help

Re: 1984 150 Mariner V6 Help

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]

Re: 1984 150 Mariner V6 Idle Issues

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]

Re: 1984 150 Mariner V6 Idle Issues

Guy, if you want help, answer the questions.