28 hp Johnson misfire when cold

[MNSubbie]

My motor is a 1994, and for the first few minutes of running will not fire one cylinder. Will occasionally fire that cylinder giving you a little "jerk" but mostly it does not fire until the motor has been running for about 5 minutes. After it warms up a little and both cylinders are firing, it will run great all day. (not sure which cylinder it is)

I have replaced both coils and the plugs, with no change in symptom.

I am thinking this is an issue with the Power Pack, but wanted to ask the forum if I am in the right track. Any and all ideas would be helpful. Thx

 

[Bosunsmate]

Re: 28 hp Johnson misfire when cold

It is suggesting powerpack, but before buying on a guess you also need to confirm its a spark problem and not a fuel one by doing a spark test. You should also check the timing too.
Run the tests for your motor, you will find it listed in here, a multimeter for $10 is handy to have around and a lot cheaper than an unneeded powerpack
ISSUU - CDI Electronics Practical Outboard Ignition Troubleshooting by CDI Electronics