79 80hp Merc Clean Bottom Spark Plug

[jeff_32]

Buddies pontoon will not accelerate. Checked compression all 4 are at 120, pulled plugs and found the bottom plug to be way too clean almost like it was just put there. Any suggestions as to what's going on?

 

[haventaclue]

Water ingress steam cleaning your bottom plug would be my guess. Have a look at your bottom seals.#11 in this schematic .Unfortunately you will need to remove the powerhead to look at them http://www.marineengine.com/parts/m...32900-usa/end-caps-manifold-and-exhaust-cover ,

 

[racerone]

Check for spark on the bottom cylinder.

 

[jeff_32]

Check for spark on the bottom cylinder.

Wouldn't this cause the exact opposite and be a loaded up spark plug if there were no spark?

 

[guyjg]

Wouldn't this cause the exact opposite and be a loaded up spark plug if there were no spark?

No...fuel/air charge would just pass thru the engine.

 

[racerone]

With no spark the plug would look like a new one.----This is based on many years of experience, I guess I forgot to mention that part.

 

[jeff_32]

No spark, thanks racerone.

 

[jeff_32]

Switched green and ground leads, number four coil is good. Stator maybe?