Here?s a heads up for those of you who may be planning a valve job on your Mercruiser 3.0. I was ready to reassemble mine when I noticed some holes in the engine block that looked to be closed up with carbon. At first I thought they were not being used and covered by the head gasket. Possibly some ports for casting purposes that had no value after. Then I placed the head gasket and noticed that there are holes over these ports. I checked the head and the ports were larger and square and also mostly blocked by rusty flakes and debris. I proceeded to clean out all four ports in the block and head. I also located one hole in the block right behind the water pump that was blocked. This looked to be the port that fed the water to these water jacket areas. I have circled these spots that became blocked to make others aware of the potential problem area.
I?m not sure if this was the only reason I had a valve tulip on my motor but I?m sure these blockages did not help matters at all. So words of the wise, if you see blocked out holes in the block make sure they are fully cleared before you start to reassemble the motor.
For those of you who are still reading my ramblings a question for you. Since my boat is raw water cooled and moored at a fresh water marina, is there anything I can do to keep this buildup from happening again? If it was a closed system a additive would be that answer.
By the way the motor runs better than new now.
Mike
I?m not sure if this was the only reason I had a valve tulip on my motor but I?m sure these blockages did not help matters at all. So words of the wise, if you see blocked out holes in the block make sure they are fully cleared before you start to reassemble the motor.
For those of you who are still reading my ramblings a question for you. Since my boat is raw water cooled and moored at a fresh water marina, is there anything I can do to keep this buildup from happening again? If it was a closed system a additive would be that answer.
By the way the motor runs better than new now.
Mike