Overheating 5.0GL-E with SX-M Outdrive (2004)

[no1nhere]

Boat was fine last year. Replaced gimbal bearing over the winter. Now engine is overheating.
1) Engine runs fine when hose is hooked to flush port.
2) Overheating in the water and on Muffs
2) Assumed it was the seal on out-drive, so I removed out-drive, cleaned up and inspected seal. All looks good, no cuts, kinks, etc. Re-torqued and tested with muffs, no good.
3) While I had the out-drive off, I hooked the hose up to the flush port and checked that there was no restriction between impeller housing and the out-drive. I also put my hand over the port on the gimbal and let it build up pressure. I didn't see any leaks anywhere. Water did come out under the anode by transom which I think would be normal? (of course all of this was with engine off)
4) Went ahead and replace impeller with OEM Volvo and thermostat.

Any Ideas? Should water come out near transom under anode when the engine is not running? I have been using muffs to test after 2,3 and 4.

 

[yoster]

If you're on muffs and engine isn't running, water won't come out below at the transom. That will only happen once the engine starts and then impeller draws the water through.

When you inspected the seal on the drive, did you also check the oring on the feed hose? The hose that connects to the rear of the transom shield and then goes into the transom? (The one with the large black plastic nut on the other side). If not, I suspect that may be the issue.

 

[no1nhere]

If you're on muffs and engine isn't running, water won't come out below at the transom. That will only happen once the engine starts and then impeller draws the water through.

When you inspected the seal on the drive, did you also check the oring on the feed hose? The hose that connects to the rear of the transom shield and then goes into the transom? (The one with the large black plastic nut on the other side). If not, I suspect that may be the issue.

Thanks for the suggestion! Now that i think about it, the way I tested by plugging the feed port, it bypasses that O-ring. I will check it today.

 

[no1nhere]

Pulled outdrive, checked O-ring. It was OK, but I went ahead and cleaned up everything and replaced it. While I had the drive off, I hooked the muffs up just to check that water was making it through easily. All looks good there too. Made sure the drive seal was in good condition and put it back together. Still overheating...

 

[dubs283]

Verify that the hoses on the sea water pump are installed correctly. Check for any blockage/restrictions between the drive pickup and sea water pump along with any impeller pieces/debris between the pump outlet and thermostat housing

 

[dypcdiver]

I chased a similar problem, does it overheat only at idle or at speed?
This was my problem between the Upper and Lower gear cases.
They have replaced it now with a stainless one but I don't know when that was actioned.

 

[no1nhere]

Verify that the hoses on the sea water pump are installed correctly. Check for any blockage/restrictions between the drive pickup and sea water pump along with any impeller pieces/debris between the pump outlet and thermostat housing

Checked everything with no issues. For sanity sake, I disconnected the raw water pump and hooked up an extra hose to the inlet with the other end in a pan of water. I tried to keep the water in the pan close to the level of the pump. With no hose on the outlet, it pumped water with no issue. With the output hoses hooked up, there was no flow at all. I let it get up to temperature as well. Still not flow. I pulled the outlet hose off at the thermostat housing. At idle, there is no flow from the water pump. the small difference in elevation is too much for the pump.
I get flow at about 3k RPM.
1) I already replaced the impeller.
2) I checked the raw water pump connections for leaks and found no issues.

I plan to pull the entire pump and see if there is anything I'm missing.
After that, a new raw water pump is in order...

 

[no1nhere]

I chased a similar problem, does it overheat only at idle or at speed?
This was my problem between the Upper and Lower gear cases.
They have replaced it now with a stainless one but I don't know when that was actioned.

Thank you! I am investigating a pressure issue with the raw water pump that may or may not have been caused by me.
Also, when I had the outdrive off, attached the muffs to see if water was making it to the inlet where the outdrive attaches to the gimbal housing and it flowed with no issues. I will keep this in mind!

 

[no1nhere]

Checked everything with no issues. For sanity sake, I disconnected the raw water pump and hooked up an extra hose to the inlet with the other end in a pan of water. I tried to keep the water in the pan close to the level of the pump. With no hose on the outlet, it pumped water with no issue. With the output hoses hooked up, there was no flow at all. I let it get up to temperature as well. Still not flow. I pulled the outlet hose off at the thermostat housing. At idle, there is no flow from the water pump. the small difference in elevation is too much for the pump.
I get flow at about 3k RPM.
1) I already replaced the impeller.
2) I checked the raw water pump connections for leaks and found no issues.

I plan to pull the entire pump and see if there is anything I'm missing.
After that, a new raw water pump is in order...

Final Update: It looks like my initial thought of it being the outdrive seal to the gimbal was the actual problem here. What occurred next was a defective wrench actuator. I completely missed the o-ring on the impeller housing. From my angle, it looked like it didn't have an O-ring, so I added a second one. The second one made the gap big enough to stop the impeller from working correctly. Add this to the list of boat fails...

 

[no1nhere]

Thank you! I am investigating a pressure issue with the raw water pump that may or may not have been caused by me.
Also, when I had the outdrive off, attached the muffs to see if water was making it to the inlet where the outdrive attaches to the gimbal housing and it flowed with no issues. I will keep this in mind!

Final Update: It looks like my initial thought of it being the outdrive seal to the gimbal was the actual problem here. What occurred next was a defective wrench actuator. I completely missed the o-ring on the impeller housing. From my angle, it looked like it didn't have an O-ring, so I added a second one. The second one made the gap big enough to stop the impeller from working correctly. Add this to the list of boat fails...

 

[dypcdiver]

Been done several times before, well documented part of the learning curve.
Go and enjoy the boat now.