Water only coming out of starboard side exhaust causing over heating

[dubman]

Hey guys, I have an old omc stringer drive, electric shift outdrive with a Chevy 350 engine. Usually the cooling system blows water out of two exhausts at the back of the boat. Recently I noticed a leak at the gasket on the port side of the outdrive where the fresh water flush system is mounted. The starboard side where the hose attaches had no leak). The water flow from the port side exhaust seemed a lot lighter then from the starboard side but it was not overheating.
I removed the leaking side and used rtv gasket repair to repair the leak. After I had finished the job I started the engine with the outdrive in a barrel of water (in other words taking in water as it would at sea) The leak seemed to have stopped but now there was NO water coming out of the port side exhaust and it started to overheat the engine.
The question I am asking is where might there be a blockage that would prevent water from flowing through the port side and out that exhaust as it is still flowing through the starboard side as normal, and, might the so called "repair" I thought I made have something to do with it.

Thanks for any help/ suggestions you might have. I have attached a pic of the engine so you can see some of the hoses. The engine has been deemed a "frankenstein" on this forum before so I am aware of it's strange appearance but it has run extremely well for four years like this.

 

[southkogs]

Typically with a Stringer, you can't simulate a true water environment with a barrel. The Stringer is designed to run submerged, so you have to force water into it with a hose or actually dunk it in the drink. With the drive in just a barrel, there's a good chance you weren't getting water up to the engine.

 

[VE8EV]

+1 to what southkogs said about not being able to run it in a barrel of water.

I'm kind of curious as to where this leak was that you fixed. Can you post a picture with an arrow to show where the water was coming out?

 

[dubman]

I'll get pics asap. As to the barrel, it's a 55 gallon container and the prop and water intake are totally submerged with a hose maintaining the level. In the past it has worked very well and as much water shoots out the exhaust as does when in the ocean. Nonetheless I believe you could be right and maybe it's just not getting enough this way all the time.

I'll get those pics and post again very soon. Thx a mill for help so far.

 

[dubman]

No Title

Here are the photos. The first is where I did the repair. You can see the blue rtv silicon coming out where the original leak was. The second is the other side of that flush unit. It's almost a mirror image of the leaking side except it has the hose connection. Once I thought the repair was complete I connected a hose and put the prop and intake under water in the drum. Even with both forms of water intake running there was still no water form the port side exhaust and it began to overheat when I started the engine.

My gut tells me the port side has a block somewhere but I haven't a clue how to trouble shoot it other then removing hoses and making sure nothing is caught in there.

 

[bruceb58]

The water has to at least be to the level of where the water pump impeller sits in the drive. If it isn't that high, you run the risk of ruining the impeller. You may have already wiped it out assuming you have been doing the barrel thing for awhile.

I would pull the hose going from the thermostat housing to the port manifold and see if you have any flow. If that looks good, I would be pulling the port riser to see how much corrosion you have in your riser and manifold.

 

[VE8EV]

Re-check that you put everything back together properly. The stainless steel plate goes on first, then the gasket, then the cap. Make sure none of the pieces got mixed up left/right or on upside down. Also check the o-rings on the pivots when you have the trunnion caps off. And of course keep your eyes peeled for a blob of silcone that got away. New trunnion gaskets are cheap and available, Sierra 18-0949

 

[dubman]

Thanks very much guys. I will start by checking the work I did again. The steel plate had a "top" notched into it so I made that the top but I'll deffo look for silicon that might have blocked something.
The thermostat idea is great too as it will at least tell me if I have any water making it from the sterndrive to that post side.

I did not realize that about the water level needing to be higher then the impeller but I will say the flow from the starboard side is as strong as ever. Would that be possible if the impeller was shot?

I'll try all of this and get back on here. I truly appreciate the help

 

[VE8EV]

I wish I could offer some better suggestions for troubleshooting but like you mentioned before, it's somewhat of a "Frankendrive" and I can't really tell from your pictures what the water flow path is to the manifolds. The original OMC had one supply hose coming from the drive to the thermostat housing and a hose from there to each manifold but I suspect yours once had (or has) a closed-cooling system which is much more complicated. Like Bruce suggested, start pulling hoses off and see where water is or isn't going.

 

[bruceb58]

Not sure why I never looked at your picture in the first post but VE8EV's post got me to look. Very weird that your manifolds are getting their water from a place other than the thermostat housing. I wonder if updating the thermostat housing to a more recent version would solve your problems.

 

[southkogs]

Is that thru-hull exhaust?

 

[dubman]

sorry Southkogs, not sure what you mean

 

[dubman]

I'm going to take a few more detailed pics of the hose set up tomorrow which will hopefully make the situation more clear. I will also try to determine where the water flow is stopping on the port side. I can only imagine it must me making it to the thermostat as the starboard side is getting water but I'll pull the hose from there first to be sure. Thx guys

 

[southkogs]

sorry Southkogs, not sure what you mean

I may not be seeing things right, but do the exhaust manifolds go straight out the back of the hull, as opposed to routing down through the sterndrive?

 

[dubman]

ahh yes. There are literally two holes in the hull with rubber flaps over them that exhaust and water sprays out of when running. Not thru the sterndrive.

 

[dubman]

No Title

UPDATE
I am attaching some pics of the hose set up on the port side. I connected the garden hose to the stern and without starting the engine I disconnected each hose from one end and saw that water was indeed flowing in each hose. Water was still coming out of the starboard exhaust with just the garden hose and no engine running but only very slight dribble from the port side. After reattaching everything I started the engine with the hose still connected but it was the same story. Light sorry from port side, full power blasting out of the starboard exhaust. The engine began to overheat and I shut it off.

 

[dubman]

And a final Update.
Realized the repair I had (thought I) made on the port side flush kit was not working and water was still leaking out. Turned out it was a stripped screw that was preventing it from tightening all the way and making the seal. This meant there was not enough pressure to push the water through the port side hoses and exhaust manifold. Took it all part and redid the repair with new screws and no RTV this time. Seems to have worked and the boat is operating normally again and not over heating. $4 fix thank goodness.

 

[VE8EV]

I'm still scratching my head about what the water flow path is through the manifolds and the block but glad to hear you're back in business.
Happy boating!