Bad ignition coils

[nolawall]

Can a Engine run with the a bad ignition coil? Will it give a indication of maybe a fuel issue but actually be the coil?

 

[Chris1956]

Gee, generally motors have 1 ignition coil for each cylinder. In this case a bad ign coil will cause 1 cylinder to miss. Some motors have only 1 ignition coil, and therefore will not run at all with a bad one.

It would help to provide year and HP of the motor you are referring to. You can normally see evidence of a missing cylinder by looking at the spark plug.

 

[racerone]

?????------What motor ?----What is your motor doing / not doing?----What trouble shooting has been done ?

 

[nolawall]

I apologize for the lack of information. The motor is a 1993 Mercury 115 4cyl 2 stroke. It ran fine then all of a sudden it just died. I can get it to idle but when I would go in gear it would just die. I have change the fuel water separator and the main fuel filter on the motor and also I just rebuild the fuel pump. I am not thinking it is the fuel system. I have pulled the gas out and looked at it and I do not se anything in the gas a far a water or debris. I am thinking in the area of a bad coil. What will I see on the plug if it is a bad coil in that cylinder? Will it be full of gas or something other than that? What kind of damage will this cause to the engine itself?

 

[racerone]

A compression test must be done first !

 

[Chris1956]

After the compression test, put the spark plugs back into their wires and ground the bases against the block and crank her. Watch for spark on each spark plug. It should be blue and make a "snap" noise.

If those two tests check out, you likely have a dirty carb issue.

 

[flyingscott]

Your motor is a 2+2 it idles on the top 2 cyl until 1800 rpm when the bottom 2 kick in do a cylinder drop test.

 

[Faztbullet]

Coils rarely go bad, In 37yr of working on motors I'll bet I changed 20 coils that where actually bad...