1 black spark plug, whats that mean?

[brian769]

1988 Mer Black Max 175

runs rough

replaced all brand new spark plugs.., i let her run for a bit..., pulled all the plugs and found one of them was black and dry looking and all the others are wet and shinny.?

What does that mean?

(engine has 2 new switch boxes, rebuilt fuel pump and cleaned carbs/new gaskets)

Any help would be greatly appreciated!!

 

[ondarvr]

Re: 1 black spark plug, whats that mean?

Check for spark on the cylinder.

 

[brian769]

Re: 1 black spark plug, whats that mean?

Check for spark on the cylinder.

yeah I got plenty of spark.. (2 new switch boxes @ $250. each)

i also checked the compression.. all checked out okay...

I can only assume that, that one cylinder is not getting fuel.?? All the others are wet and shinny when i pull em.

I just took the carbs apart and cleaned them... Looks like I'm gonna have to do it again.???