1980 70hp running problem

[Cassi8u99]

I am having a hard time starting my motor and then when i do get it started it seems to be running on 2 cylinders. As i slowly accelerate (over 400 yards) to full throttle the third cylinder starts to fire and then the motor runs fine. After about 5 minutes at full throttle the motor suddenly dies. Upon restarting its running on 2 cylinders again.

I am not overheating, there is good water flow through the motor. I am getting gas. I think this is an electrical problem. Can anyone offer any tips on how to troubleshoot the problem to the faulty component. I dont just want to start trowing parts at it until it works.

thanks,
Casper

 

[tashasdaddy]

Re: 1980 70hp running problem

Welcome to Iboats. start with check the compression, and spark check on all cylinders, what do the plugs look like. black wet, light brown dry, gunky? give us these results so we have something to work with. you are the eyes and ears, for us.

 

[Cassi8u99]

Re: 1980 70hp running problem

i just changed all 3 sparkplugs... all seemed black and wet. 1 had a small amount of black gunk on it.

 

[tashasdaddy]

Re: 1980 70hp running problem

check compression, and spark.