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Old 08-03-2020, 01:01 PM
Senior Member
Join Date: Sep 2019
Location: York, ME
Posts: 118
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Default Johnson 90hp (J90PLEEB) issues

Last season I had purchased a boat and up to last past Friday, the motor Johnson 90hp (J90PLEEB) has run very smoothly and strong. On Friday, I was about 7 miles out, had stopped to do some fishing off the Island of Sholes and the motor did not want to start and when it did, the motor ran very rough, sounded like 1 to 2 cylinders were not firing. I should mention that on my way out, the ocean was glass and I was able to maintain ~22mph for the whole 7 miles.

Before pulling the boat from the water, I shot some decarb spray in each intake and you could hear the motor rev higher and the excess smoke. However, when flushing the motor, it continued to sound like 1 to 2 cylinders were not firing.

Yesterday, I had started up the motor, let it warm up and then pulled the plugs and tested the compression. All cylinders were right around 90 psi, which is the same as when I had purchased the boat last season. I then reconnected the plugs and started to pull 1 plug at a time to see how the motor responded.

Pulled bottom right cylinder plug and the motor had no change. However, you could hear there is a spark.
Pulled the top right cylinder plug and the motor would die.
Pulled the top left cylinder plug and the motor idle lowered.
Pulled the bottom left cylinder plug and the motor idle lowered.

While I ordered the carb rebuild kits and 4 new bowls, will clean/rebuild when they arrive.

Should I be looking at the power packs or something else?

I have added photos of the spark plugs, how do they look? These were installed in June and the boat has been used 12 times.

Video of the motor running

Last edited by TopherMichael; 08-03-2020 at 01:17 PM.