Engine overheating

[nateo]

Well just put in about 50 hours of work replacing water pump impeller and housing, motor mount, and engine coupler. Not a good father so far. I put it on mufs, drive shaft is spinning properly now. However doesn't seem to be circulating water very well. It seemed to spit water out of impeller ok but nothing out of bell housing. Let engine run for a minute and finally got water coming out of bell housing but only one side. Temp seemed a little high still but stopped rising. Now it didn't even seem like it sucking water in anymore. Anything I can try before removing outdrive and trying to run on hose?

 

[nateo]

well I did a little test. I removed water inlet hose from transom and put garden hose in there. Boat drank it and spit out of bell housing. Didn't run very long at all like this. So I guess that leaves something with outdrive or water inlet tube plugged up? Any other ideas. Heck I replaced the water pump housing and impeller. Put all new gaskets in water pump. Make sure key was inserted correct as I turned the prop a little and made sure impeller was spinning before I closed everything up.

 

[beech2000]

Is the water line kinked or restricted from Drive to transom / transom to power steering cooler? good water flow from outlet of power steering cooler?
How about the exhaust risers or riser gaskets? Have you inspected for cracks? Spark plugs read normal?

 

[Bondo]

Heck I replaced the water pump housing and impeller.

Ayuh,.... Were there any missin' pieces of the old impeller,..??

Did ya find All of 'em,..??

 

[nateo]

Ok, so I think I might have found the smoking gun. I found a rubber o-ring in driveway near where I reinstalled outdrive. Cracked the outdrive loose and sure enough, the water inlet o-ring fell out when I was putting drive back on. Reinstalled o-ring but still same results. Thinking I probably burned up impeller during troubleshooting. During t-shooting temp got up to 200 but I haven't ran the boat or anything, just idle speed. Am I likely going to need to replace water pump housing again? Just wondering how long does it take to warp it in a high temp overheating situation?

 

[beech2000]

Ok, so I think I might have found the smoking gun. I found a rubber o-ring in driveway near where I reinstalled outdrive. Cracked the outdrive loose and sure enough, the water inlet o-ring fell out when I was putting drive back on. Reinstalled o-ring but still same results. Thinking I probably burned up impeller during troubleshooting. During t-shooting temp got up to 200 but I haven't ran the boat or anything, just idle speed. Am I likely going to need to replace water pump housing again? Just wondering how long does it take to warp it in a high temp overheating situation?

lack of water to impeller is usually what melts it. Not engine heat. There is a thick rubber seal in the lower drive exhaust path. Did you make sure this piece was installed? Also what about the upper drive tubes from the water pump outlet? Did you inspect and replace the o-rings in the coupler?