My family has a place up in northern Wisconsin on a lake. We have a couple boats. One is a older pontoon boat with a mercury 25hp outboard motor on it.
It has been running like crap. It would run fine for a while, then it would just go south and barely run. My inlaws and I were getting sick of dealing with it.
I tore into it and started troubleshooting. The boat was at the pier in the water so it was a fun balancing act trying my best not to fall in the water.
I pulled the plugs after running it briefly and noticed one was cold, the other was hot. The cold one was also very fouled out. I put new plugs in it and the same thing happenned. One was cold, the other warm. So it was running on one cylinder (the top one) and the problem was not the plugs. So, next I swapped the coils and plug wires from top to bottom. The problem didn't change, the bottom cylinder was still cold.
Conclusion: the ICM was not firing the bottom cylinder. I know the coil is good, the plug and wire are good and it is getting fuel. I also know it has good compression because I stuck my thumb over the hole and gave the rope a pull.
I yanked the ICM off, gave it to my brother in law and showed him how to reinstall the new one, when he gets it.
He picked up a new ICM, installed it and the boat runs perfectly now. Gosh, I'm good! The new (used actually because brand new ones are over $200) ICM was $80, so he called me before he bought it asking me if I was absolutely sure that was the problem. I told him I was sure, man was he impressed when it turned out I was right.
It has been running like crap. It would run fine for a while, then it would just go south and barely run. My inlaws and I were getting sick of dealing with it.
I tore into it and started troubleshooting. The boat was at the pier in the water so it was a fun balancing act trying my best not to fall in the water.
I pulled the plugs after running it briefly and noticed one was cold, the other was hot. The cold one was also very fouled out. I put new plugs in it and the same thing happenned. One was cold, the other warm. So it was running on one cylinder (the top one) and the problem was not the plugs. So, next I swapped the coils and plug wires from top to bottom. The problem didn't change, the bottom cylinder was still cold.
Conclusion: the ICM was not firing the bottom cylinder. I know the coil is good, the plug and wire are good and it is getting fuel. I also know it has good compression because I stuck my thumb over the hole and gave the rope a pull.
I yanked the ICM off, gave it to my brother in law and showed him how to reinstall the new one, when he gets it.
He picked up a new ICM, installed it and the boat runs perfectly now. Gosh, I'm good! The new (used actually because brand new ones are over $200) ICM was $80, so he called me before he bought it asking me if I was absolutely sure that was the problem. I told him I was sure, man was he impressed when it turned out I was right.
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