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Cooling water coming out of mid section

Jupiter Dinghy

Jupiter Dinghy

Regular Contributor
I took the 1979 Evinrude 9.9hp with a new water pump/impeller out for a spin today and I noticed something strange: The cooling water coming out of the exhaust hole underneath the power head at the back, was coming out nicely (very hot but a wide and thick spray as it is supposed to be) and as soon as I was opening the throttle wide to get on plane, the water stream would stop. I roll the throttle back and the water starts spraying again as it should.

If I had not just replaced the water pump, I would think it might be a pump or impeller issue, but here is what I found out when I got home and hooked up the ears to flush the motor: You will see on the pics below the black arrows pointing out where the water is coming out.
Weak at low RPM (first pic) and getting much stronger when revving up the motor (second pic), which would explain why the water stopped coming out of the exhaust hole at high RPM as it is "diverted" through this area of the mid section, instead of following its route through the power head.




Anyone has seen / encountered this before? And any suggestion as to what needs to be done to fix this?

Thanks
 
Water is supposed to come out there. You may be getting more than normal because of water pressure from the hose.
 
I think you will find it is coming from where the shift rod passes from the swivel tube into the "foot". There should be a grommet there. it is probably missing.

Marked up in red on the parts diagram

n6f514.jpg
 
fdrgator said:
Water is supposed to come out there. You may be getting more than normal because of water pressure from the hose.
Click to expand...

Well, that's good news, thanks.
I thought it was weird because there is no water coming out on the other side (starboard).
Any idea what may cause the exhaust stream to stop when going full throttle?
 
vics said:
I think you will find it is coming from where the shift rod passes from the swivel tube into the "foot". There should be a grommet there. it is probably missing.
Marked up in red on the parts diagram
Click to expand...

Thanks Vics. Sounds about right, but then is water supposed to come out of here or not?
Looks like a fun party trying to access this grommet (or lack thereof) for replacement/instal!.....:(

And just to confirm:The water coming out of this exhaust hole IS supposed to be burning hot right?
Thermostat opens around 140 degrees (Farenheit) if I recall correctly, so does this mean it is what the exhaust water temp should be approximately?
 
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Jupiter Dinghy said:
Thanks Vics. Sounds about right, but then is water supposed to come out of here or not?
Looks like a fun party trying to access this grommet (or lack thereof) for replacement/instal!.....:(

And just to confirm:The water coming out of this exhaust hole IS supposed to be burning hot right?
Thermostat opens around 140 degrees (Farenheit) if I recall correctly, so does this mean it is what the exhaust water temp should be approximately?
Click to expand...

I don't think it matters that water is coming out of there. I am not even sure that the grommet makes a watertight seal around the shift rod.

I not like to comment on the rest of your post by I feel something is not quite right. "Burning hot" water I'm sure is not right and I don't understand the other things you observe but the increase in the flow in your pictures may be because at higher speed the pump pumps more water.

Checking the thermostat may be a good idea.

Id also be suspecting that cooling water may be leaking from the pump discharge. Bad water tube grommets or even a perforated water tube????

You '79 engine should have a telltale ?? Are you getting a good flow from that ?

There is a lot of info on LeeRoys Ramblings that may be relevant.

http://leeroysramblings.com/Outboard Motor Related/OMC outboard related articles.html
 
Water is supposed to come out there. It is water that has escaped the water pump via the hole in the pump housing that the drive shaft passes through. There are one or two large drain holes for the water to get out after it has escaped from the pump. If it did not drain off, it would fill up the drive shaft isolation tube and cause severe damage up above.

This is not to deny there might be additional water leakage adding to the intentional water drainage. I wouldn't worry about it without more evidence. As I suggested, it may simply be because it is running on a hose.

If you are trying to diagnose an overheat situation by running on a hose, you are wasting your time. A water pump does not "pump" while running on muffs, it only allows hose water to pass through.
 
vics said:
I don't think it matters that water is coming out of there. I am not even sure that the grommet makes a watertight seal around the shift rod.

I not like to comment on the rest of your post by I feel something is not quite right. "Burning hot" water I'm sure is not right and I don't understand the other things you observe but the increase in the flow in your pictures may be because at higher speed the pump pumps more water.

Checking the thermostat may be a good idea.

Id also be suspecting that cooling water may be leaking from the pump discharge. Bad water tube grommets or even a perforated water tube????

You '79 engine should have a telltale ?? Are you getting a good flow from that ?

There is a lot of info on LeeRoys Ramblings that may be relevant.

http://leeroysramblings.com/Outboard Motor Related/OMC outboard related articles.html
Click to expand...

Yes, very familiar with Leeroy, and I forgot to mention I also replaced the thermostat on this motor.
I agree with your leak assessment. I think I'm losing water along the way, possibly at the pump/water tube junction. I will inspect.
Thanks again for chiming in.
 
fdrgator said:
Water is supposed to come out there. It is water that has escaped the water pump via the hole in the pump housing that the drive shaft passes through. There are one or two large drain holes for the water to get out after it has escaped from the pump. If it did not drain off, it would fill up the drive shaft isolation tube and cause severe damage up above.

This is not to deny there might be additional water leakage adding to the intentional water drainage. I wouldn't worry about it without more evidence. As I suggested, it may simply be because it is running on a hose.

If you are trying to diagnose an overheat situation by running on a hose, you are wasting your time. A water pump does not "pump" while running on muffs, it only allows hose water to pass through.
Click to expand...

Understood and agreed about the muffs, I usually flush the motor in a test tank but just wanted a visual on the water circulation (that you don't get with motor submerged). As far as the water coming out of the exhaust hole behind the motor, am I wrong in assuming it should be at about 140/150 which is thermostat opening temp?
 
Yes the water should be hot as it drips off your fingers. If it stays cool you thermostat is either stuck open or not present. Some guys (idiots) will pull the thermostat thinking it will help. If the engine does not reach temp you will shorten the life of the motor.
 
fdrgator said:
Water is supposed to come out there. It is water that has escaped the water pump via the hole in the pump housing that the drive shaft passes through. There are one or two large drain holes for the water to get out after it has escaped from the pump. If it did not drain off, it would fill up the drive shaft isolation tube and cause severe damage up above.

This is not to deny there might be additional water leakage adding to the intentional water drainage. I wouldn't worry about it without more evidence. As I suggested, it may simply be because it is running on a hose.

If you are trying to diagnose an overheat situation by running on a hose, you are wasting your time. A water pump does not "pump" while running on muffs, it only allows hose water to pass through.
Click to expand...

The drive shaft passes through a seal in the top of the water pump #39 in the parts diagram. The purpose of this seal is to prevent air being drawn in if the pump is not fully submerged although on a hose water may well be forced out past it if it is worn ( or missing). Hopefully Jupiter Dinghy renewed this seal when he replaced the impeller, if it was defective. It is included in the water pump kit.

convert
 
Happy update: I found the culprit, and the issue is resolved!
So I took the foot off again and started to inspect the pump for the aforementioned seals and o ring, and everything was where it was supposed to be, but since I had a strong feeling that I was losing water at the pump/water tube junction, I pulled the rubber boot from the pump to check how the fitting was on the water tube (and yes, I should have done that BEFORE putting everything back together), and sure enough, I realized I had used the wrong boot (the water pump assembly comes with several), it had about one millimeter play on each side of the tube.... so no wonder where my water was going.
I found the one with the right fit, put everything back together, and like magic, water came out of the exhaust hole on the muffs, and MUCH cooler than it used to be before.
Just to make sure everything was back to normal, I took the dinghy out for a spin on the water, and now not only do I have water coming out the exhaust hole when picking up RPM's, but I could feel the temperature actually going down when going full throttle, as it should, given the increased amount of water getting pumped and pushed up by the impeller at higher RPM.
Color me happy, and thanks to all for your inputs. :D
 
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Jupiter Dinghy said:
Happy update: I found the culprit, and the issue is resolved!
So I took the foot off again and started to inspect the pump for the aforementioned seals and o ring, and everything was where it was supposed to be, but since I had a strong feeling that I was losing water at the pump/water tube junction, I pulled the rubber boot from the pump to check how the fitting was on the water tube (and yes, I should have done that BEFORE putting everything back together), and sure enough, I realized I had used the wrong boot (the water pump assembly comes with several), it had about one millimeter play on each side of the tube.... so no wonder where my water was going.
I found the one with the right fit, put everything back together, and like magic, water came out of the exhaust hole on the muffs, and MUCH cooler than it used to be before.
Just to make sure everything was back to normal, I took the dinghy out for a spin on the water, and now not only do I have water coming out the exhaust hole when picking up RPM's, but I could feel the temperature actually going down when going full throttle, as it should, given the increased amount of water getting pumped and pushed up by the impeller at higher RPM.
Color me happy, and thanks to all for your inputs. :D
Click to expand...

Thanks for the feed back.

Its always nice to know what the trouble really was , and that it has been sorted successfully.
 
Jupiter Dinghy said:
Happy update: I found the culprit, and the issue is resolved!
So I took the foot off again and started to inspect the pump for the aforementioned seals and o ring, and everything was where it was supposed to be, but since I had a strong feeling that I was losing water at the pump/water tube junction, I pulled the rubber boot from the pump to check how the fitting was on the water tube (and yes, I should have done that BEFORE putting everything back together), and sure enough, I realized I had used the wrong boot (the water pump assembly comes with several), it had about one millimeter play on each side of the tube.... so no wonder where my water was going.
I found the one with the right fit, put everything back together, and like magic, water came out of the exhaust hole on the muffs, and MUCH cooler than it used to be before.
Just to make sure everything was back to normal, I took the dinghy out for a spin on the water, and now not only do I have water coming out the exhaust hole when picking up RPM's, but I could feel the temperature actually going down when going full throttle, as it should, given the increased amount of water getting pumped and pushed up by the impeller at higher RPM.
Color me happy, and thanks to all for your inputs. :D
Click to expand...
 
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