1 spark plug does not fire

[justin7464]

i have a 1993 8 hp johnson model # E8RETB the top spark plug fires sometimes and i can start the engine on the first pull other times i can pull all day and the plug will not fire

when i do get it started the plug stops fireing and runs on the bottom plug alone but will not get enough power to do much of course

i have cleaned the carb, replaced the spark plugs, replaced the ignition coil

neutral engine roars forward it dogs right down and have to have it full boar to get it to keep running any ideas?

 

[CATransplant]

Re: 1 spark plug does not fire

Start by checking compression on the top cylinder and compare it to the bottom cylinder. If it's low, then you could have a bad head gasket or other problems in that cylinder.

If compression is OK, put a new plug in that cylinder and try again.

If still no go, you'll need to use the factory manual to diagnose the problem with the ignition system.

A plug that looks good can still be bad. A plug wire that looks good can also be bad. Those are easy fixes. You've replaced the coil, so if it's not one of those two things, it's a problem further back in the ignition system. By following the factory manual's diagnostics, you can pin it down.

 

[mikesea]

Re: 1 spark plug does not fire

disconnect your kill switch and see if it runs,they go bad often,intermittent is a common problem

 

[justin7464]

Re: 1 spark plug does not fire

got it bad power pack was kicking in and out tapping it on the side made the spark plug fire will replace it tomorrow