Hello,
I recently bought a 1993 Johnson 9.9 2 stroke outboard. It was sitting for close to 20 years but the previous owner ran it out of gas before putting it away in a barn. He claims that it was only ran 3 times and it looks brand new under the cover. When I hooked up a fresh tank of gas it ran flawlessly. After that I had it out around 5 days and it was running perfectly. Last week when I had it out it started running very rough throughout the entire RPM range. I got home and took the spark plugs out. The top plug looked perfect but the bottom was very wet. I checked compression and I have 110 PSI in both cylinders. I checked my spark with an inline spark tester and the spark is extremely strong. The carburetor is very clean and fuel pump is working as it should. I replaced my spark plugs just to be sure and had no changes but when I unplug the bottom spark plug wire it doesn’t change how it runs but when I unplug the top plug the motor stops so it is only running on the top cylinder. Any pointers or advice would be very helpful and appreciated.
Thanks.
I recently bought a 1993 Johnson 9.9 2 stroke outboard. It was sitting for close to 20 years but the previous owner ran it out of gas before putting it away in a barn. He claims that it was only ran 3 times and it looks brand new under the cover. When I hooked up a fresh tank of gas it ran flawlessly. After that I had it out around 5 days and it was running perfectly. Last week when I had it out it started running very rough throughout the entire RPM range. I got home and took the spark plugs out. The top plug looked perfect but the bottom was very wet. I checked compression and I have 110 PSI in both cylinders. I checked my spark with an inline spark tester and the spark is extremely strong. The carburetor is very clean and fuel pump is working as it should. I replaced my spark plugs just to be sure and had no changes but when I unplug the bottom spark plug wire it doesn’t change how it runs but when I unplug the top plug the motor stops so it is only running on the top cylinder. Any pointers or advice would be very helpful and appreciated.
Thanks.