PontoonDIYFixer2B
New member
Hello. Newbe here looking for help please. I have a 2000 90hp Mercury 2 stroke outboard 3 cylinder outboard.
Last week, the top cylinder was not firing. I know because I did not get shocked when pulling off the spark plug boot while motor was running, like when pulling off the other 2 spark plug wires and also verified no spark by putting another spark plug in the boot and verified no spark gapping to ground.
I took the wire harness connector off the middle CDM and put it on the top CDM and had no spark still. Then I took the top CDM connecter and plugged it into the middle CDM and moved the plug wire to the top plug and verified I was getting a spark at the top cylinder. Sure looked to me like the top CDM was bad.
Today, I replaced the top CDM with a new one from the Mercury dealer, and the motor started right up. I thought my issues were over and went for a test spin. To my surprise, I was only running on 2 cylinders still. Top RPM was still only 4200. I took the motor cover off and pulled the spark plug wire and got no shock, so I ending the test spin.
At the dock I verified no spark coming from the top brand new CDM module. I did some searching on this site and then took the new module and put it in the middle, taking the middle module and putting it in the top. The top cylinder now fires and the middle does not. I tried the older CDM in the middle and same result. I tried using the wire connector from the bottom CDM and plugging it into the new and the older top CMD…
Anyway, now only the top cylinder is firing and the middle and lower CDMs are not. The engine will start on 1 cylinder and run. I have experience with Cars, but not boat engines. Guess after 15 years of owning this Outboard, it's time for things to start failing… Thank you
Oh; is the top clinker #1, and middle #2 and bottom #3? Could the voltage regulator be bad - i tried making sure the connections to it were good and it looked like one of the yellow connections was slightly melted/black…
Last week, the top cylinder was not firing. I know because I did not get shocked when pulling off the spark plug boot while motor was running, like when pulling off the other 2 spark plug wires and also verified no spark by putting another spark plug in the boot and verified no spark gapping to ground.
I took the wire harness connector off the middle CDM and put it on the top CDM and had no spark still. Then I took the top CDM connecter and plugged it into the middle CDM and moved the plug wire to the top plug and verified I was getting a spark at the top cylinder. Sure looked to me like the top CDM was bad.
Today, I replaced the top CDM with a new one from the Mercury dealer, and the motor started right up. I thought my issues were over and went for a test spin. To my surprise, I was only running on 2 cylinders still. Top RPM was still only 4200. I took the motor cover off and pulled the spark plug wire and got no shock, so I ending the test spin.
At the dock I verified no spark coming from the top brand new CDM module. I did some searching on this site and then took the new module and put it in the middle, taking the middle module and putting it in the top. The top cylinder now fires and the middle does not. I tried the older CDM in the middle and same result. I tried using the wire connector from the bottom CDM and plugging it into the new and the older top CMD…
Anyway, now only the top cylinder is firing and the middle and lower CDMs are not. The engine will start on 1 cylinder and run. I have experience with Cars, but not boat engines. Guess after 15 years of owning this Outboard, it's time for things to start failing… Thank you
Oh; is the top clinker #1, and middle #2 and bottom #3? Could the voltage regulator be bad - i tried making sure the connections to it were good and it looked like one of the yellow connections was slightly melted/black…
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