johnson 150 ois 2000 runs rough

[Looney2002]

My johnson 150 was running rough and a mechanic said I needed a new power pack. So I replaced it and the optical sensor. Took back to get the carbs synced and they said it wasn't getting spark on the port bank. So I brought it home to check it out. I hooked up a spark tester and saw spark on all 6 cylinders. Not sure what to check for next. I just want to get it running right.

 

[racerone]

I would check the shift interrupt switch on this motor.

 

[Docksidemarineservices]

I would check the shift interrupt switch on this motor.

So would I.

 

[Boobie]

The shift interrupter was always on the starboard bank unless OMC changed it.

 

[Looney2002]

I have check that and it seems to be fine. Could it be the quick start or temp switch

 

[Boobie]

Do a cylinder drop test on it when running and see which cylinders aren't firing.

 

[Looney2002]

How do I do a cylinder drop test

 

[leaky]

How do I do a cylinder drop test

Usually that means to take a pair of insulated pliers (so you don't get zapped) and pull the spark plug wires off with the engine running. The idea is if it doesn't change anything then it wasn't firing on that cylinder.

With some engines it's more obvious than others when dropping a cylinder at idle; I'd think you should be able to hear the difference though.

Jon

 

[Looney2002]

I guess I will do that tomorrow. What is weird to is I checked spark today and got spark on all six cylinders. When it is running the rpm is jumping from 650 to 800.

 

[Boobie]

Run it about 2000 rpm when doing the cylinder drop test.