Overheating after water pump service

[TheRussian]

Hello,

​I have just replaced my water pump housing and impeller with an OEM kit (Alpha 1 Gen 2) for my very first time. I was pretty confident that I followed the instructions very well. The only thing that I have done slightly differently is use liquid gasket sealer on the gaskets of the metal housing, but there is a service bulletin that allows for that I believe.

I have started the boat for the first time today after winter storage on the muffs. I noticed that there was no water being discharged from the transom but thought maybe the engine just needs time to warm up. However, once the temp gauge began to rise, it quickly (within 10-20 secs) reached the max temp. I was able to see this rise and quickly shut the engine off.

I removed the drain plugs from the manifolds and they were pretty much dry!? I would think that the only thing that this could mean is that water is not being circulated in the engine?

Could you please help troubleshoot? Do I need to remove the impeller to inspect now or should I try something else first?

Thanks!

 

[Rick Stephens]

Probably best to pull the outdrive and inspect the impeller. Maybe missing the key? With the drive off you should be able to turn the input shaft and feel the resistance of the impeller.

I've not been one to ever use sealants on the water pump. There is water on both sides, the oil seal under it is the only thing that can't be allowed to leak. Taking apart the pump after sealing the gaskets is a lot more labor for no benefits.

Run for 8-10 minutes dry, if the impeller was turning it is almost certainly toast.

Rick

 

[TheRussian]

Would it make any sense to take the outdrive off and run the boat with a water hose plugged into the water pick-up hole on the bellhousing? (I also had water hose replaced with the bellows but it is not kinked). I would think that this would narrow the problem down to either the engine or the outdrive. I have brand new gear oil in and don't want to drain it if it is not necessary.

 

[Newbie@boats]

If it didnt over heat BEFORE.....and now it over heats......remove drive and check the job

 

[Rick Stephens]

Would it make any sense to take the outdrive off and run the boat with a water hose plugged into the water pick-up hole on the bellhousing? (I also had water hose replaced with the bellows but it is not kinked). I would think that this would narrow the problem down to either the engine or the outdrive. I have brand new gear oil in and don't want to drain it if it is not necessary.

In my humble opinion, you cannot trust that the impeller is still intact after no water flowed into the engine.

 

[TheRussian]

I will pull the outdrive tomorrow and inspect the water pump. Hopefully I just made a mistake somewhere and a new impeller will solve the problem (I am sure that the new one that is in there now is fried but I hope that I can clean up the housing since it is brand spanking new).

 

[Rick Stephens]

That heavy stainless housing will be fine.

 

[TheRussian]

So I am a little confused. I have pulled the drive today and disassembled the gearcase. Here are the findings:​

1. The seal on top of the pump housing is intact
2. The key is in the correct place and the impeller spins with the shaft
3. The impeller is in perfect condition - no signs of any wear on it or the housing
4. The water guide tube was in place
5. The water passages in the gear case do not appear to be occluded - I can see light under the water pump housing and I was able to blow air through the upper housing passage
6. The engine ran well with water hose connected to the bellhousing. Temperature remained steady and there was lots of water discharged from the transom
7. I also changed the shift cable this year but don't see how it could effect the water pump since it is always on during engine operation, but thought I would mention it

Does anyone have any suggestions before I start the assembly? Also, am I OK to re-used the pump seals as well as the outdrive seal between the gearcase and the bellhousing? All seals were brand new this season, no boat use.

I have also misplaced the plastic piece to install the seal on top... can I just do it by hand?

Thanks.

 

[Bt Doctur]

If it runs ok on a hose and not the drive the only thing in between is the impeller assembly. When you installed the impeller did you :
insert it into the housing with your left hand rotating it CCW
place the impeller on the driveshaft and place the SS housing over the impeller turning the driveshaft CW

 

[Rick Stephens]

Only other thing I can think of is something plugged up.

Your seals should be fine for many seasons.

 

[TheRussian]

I have reassembled the outdrive and installed it back on the boat. The impeller appears to have been installed the correct way the first time Doctur. The only thing that I have noticed is that I installed the outdrive-bellhousing seal backwards, but that would not block the water passage.​

Now everything seems to be working! Not sure why, but I can't complain. I will run the boat some more tomorrow and hopefully do a water test soon.

Thanks for all your wisdom.