When I opened up the powerhead of my 115 Johnson I discovered definite evidence of some overheating on the left side. Before putting it back together I want to be sure everything is right with the water passages. I have spent the better part of the morning studying the powerhead and trying to understand the water passages and have acomplished nothing but confusing myself. I would like to ask a few questions to help shed light on the subject.
1. I removed the lower unit and connected a water hose to the water tube to locate where water enters the powerhead. When I turned on the water it flowed out of a small rectangular hole on the right side of the midsection to powerhead mating surface. I then set the gasket on top of the midsection and located the hole for the above mentioned rectangle in the gasket. Then I took the gasket in and laid it on the bottom of the powerhead to locate the intake hole. No hole lined up with this rectangular shaped hole. Further inspection revealed a small channel in the midsection of the motor that lead to a tiny hole in the gasket about the diameter of an 8d nail. This hole lined up with a hole in the bottom of the powerhead. Does the powerhead really get all it's cooling water through this tiny hole or am I missing something?
2. The above mentioned hole apears to me to lead into the large cavity in the middle of the block that you can see into by removing the inspection port under the flywheel. It apears to me that hole fills the cavity then water spills over into the space between the inner and outer exhaust cover. Am I correct?
3. At the bottom of the large cavity there apears to be one hole on each side that leads to the passages around the cylenders. I assume that those holes fill the passages then water flows out the holes at top of the cylender heads to the thermostats. I would assume when the thermostats open it lets more water flow out increasing the flow?
If this is correct I just have a couple more questions.
1. My manual has a diagram showing the direction of water flow through the cylender heads. It shows arrows pointing up one side of the head, over the top and down the other side. This makes no sense to me if my earlier assesment is correct and the exit ports are at the top, wouldn't water flow up both sides of the cylender and out the top?
2. There is a small hole (almost a pinhole) at the rubber diverter in the passages between cylender 1&3 and 2&4. What is this hole for and should it be cleaned out and how would I clean it if needed?
Thanks
1. I removed the lower unit and connected a water hose to the water tube to locate where water enters the powerhead. When I turned on the water it flowed out of a small rectangular hole on the right side of the midsection to powerhead mating surface. I then set the gasket on top of the midsection and located the hole for the above mentioned rectangle in the gasket. Then I took the gasket in and laid it on the bottom of the powerhead to locate the intake hole. No hole lined up with this rectangular shaped hole. Further inspection revealed a small channel in the midsection of the motor that lead to a tiny hole in the gasket about the diameter of an 8d nail. This hole lined up with a hole in the bottom of the powerhead. Does the powerhead really get all it's cooling water through this tiny hole or am I missing something?
2. The above mentioned hole apears to me to lead into the large cavity in the middle of the block that you can see into by removing the inspection port under the flywheel. It apears to me that hole fills the cavity then water spills over into the space between the inner and outer exhaust cover. Am I correct?
3. At the bottom of the large cavity there apears to be one hole on each side that leads to the passages around the cylenders. I assume that those holes fill the passages then water flows out the holes at top of the cylender heads to the thermostats. I would assume when the thermostats open it lets more water flow out increasing the flow?
If this is correct I just have a couple more questions.
1. My manual has a diagram showing the direction of water flow through the cylender heads. It shows arrows pointing up one side of the head, over the top and down the other side. This makes no sense to me if my earlier assesment is correct and the exit ports are at the top, wouldn't water flow up both sides of the cylender and out the top?
2. There is a small hole (almost a pinhole) at the rubber diverter in the passages between cylender 1&3 and 2&4. What is this hole for and should it be cleaned out and how would I clean it if needed?
Thanks