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Water leak in housing on Honda 8 hp four stroke

Crossthread

New member
Good morning. I have a Honda 8 HP four stroke long shaft on my sailboat. I recently started it up and noticed water flowing from an area I had not noticed before. It is coming from between I think they call it the exhaust cover and the lower unit. The engine runs great and no overheating. Is this normal and I just haven't noticed it before? Thanks very much.

leak.jpg
 
Hi,
It seems to be coming from the seam between the side cover and the extension case. There is a molded black seal for this seam on the bottom of the side covers but yours appears to be missing. However, the seal wasn't designed to keep water in but to keep water out I believe.

While it's not normal for cooling water (if that's what it is) to exit there,
it doesn't mean anything is majorly amiss. Exhaust and water are intended to be inside the extension case but should exit, for the most part, around the prop. Is the water that's flowing there hot?

If the water is warm or hot, it is exhaust. But if the engine is warm and the water coming out of the seam isn't, then it could be coming from the water tube that tranfers water from the pump up to the engine. This may be because the rubber grommet the tube connects to, up inside the extension case, has failed in some way. If that's the case, it could, at some point, cause your engine to overheat.

Removing the side cover and, ultimately, the gearcase to inspect may be necessary to find out what's happening.
 
jgmo...Thanks so much for the reply. I don't know if the water is hot because I didn't check it. Are you saying that there should be a gasket/seal where the arrow is pointing? I'm not sure what those parts are called. I have always referred to the very bottom section where the gears and water pump are as the lower unit. Not sure what the upper section is called. I think I saw it called an exhaust cover but not sure. I know there is a skirt that attaches to the engine proper that I have to remove to service the engine. It goes down to what I guess is the lower unit and that junction is where the leak is occurring. Thanks again.
 
jgmo...Thanks so much for the reply. I don't know if the water is hot because I didn't check it. Are you saying that there should be a gasket/seal where the arrow is pointing? I'm not sure what those parts are called. I have always referred to the very bottom section where the gears and water pump are as the lower unit. Not sure what the upper section is called. I think I saw it called an exhaust cover but not sure. I know there is a skirt that attaches to the engine proper that I have to remove to service the engine. It goes down to what I guess is the lower unit and that junction is where the leak is occurring. Thanks again.
 
Lower unit = gear case or transmission assembly. Everyone has a different name for it.

Exhaust cover?....I'm not sure about that. I haven't come across that term yet.

The gearcase is bolted up to the extension case and the extension case is bolted to the oil case.
The engine sits atop and is bolted to the oil case.
Two removeable "side covers" and the hood or engine cover completes the "body" of the outboard.

The side covers, particularly the right side one, must be removed for regular maintenance. The right cover contains the nozzles for draining the carburetor and the water pump tell tale. It also has to be removed to drain the engine oil and replace the oil filter.
 
Thanks again. Going forward I will refer to it as the extension case. So there is supposed to be a gasket/seal between the extension case and the lower unit is that correct? I sent an email to Honda with the picture of the issue and they were extremely unhelpful in that they said take it to a dealer. I can't imagine this is a huge problem because it runs so well. As you pointed out to me the side covers need to come off to service the engine. It is entirely possible that the last time I serviced it I did not put the gasket/seal in the proper place. I guess the bottom line is that I need to pull off those covers and check. My original question was "is this normal"? You say it is not so I will dig further. Thank you so much for your help.
 
There is a molded seal that sits on top of of the perimeter of the extension case. They can deteriorate over time.

Yes, take the starboard (right) side cover off and make sure your tell tale hose is routed properly. Most "newbies" install those wrong after having the cover off. It has to be routed in such a way that it goes down through the hole in the splash plate and is not pinched against the edge of the plate when the side cover is put back on. It's one of those items that only goes on one way to be correctly placed but it will go on incorrectly very easily.

If you don't find the reason for your leak on that side, then pull the port (left) side cover and look for anything wrong on that side. The thermostat housing is there and it has a flush valve that can leak profusely when it doesn't seal. Sometimes it can simply cleaned up and it will seal but the spring and little valve aren't expensive if they need replacement.

Good luck and let us know what you find.

P.S. a good quality impact driver makes getting the screws on these covers loose much easier without ruining the heads.
 
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Ok, no hurry on my part. I will be standing by.

And a very Merry Christmas to you too Crossthread!
 
Well jgmo I found the leak. After an exhaustive investigation and forming a task force to study the data I noticed that the engine was peeing on my foot. DUH. The picture is of the telltale hose coming from the block to the cowl. Good thing is nothing was really that wrong and I suspected that because it ran so well. I stuck a business card up in the tube to give it a little contrast. Now the next problem is replacing it since Honda in all their eminent wisdom made the tube 3/8 on one end and 1/4 on the other. Can't find it in stock anywhere. Thanks so much for your help.

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See item 35 in part page link below.

91402-ZW9-000 Tube, water check

https://www.boats.net/catalog/honda...8d4-lha-2004/shift-shaft-handle-specification

Why they make parts so hard to find is a mystery to me. But it's a Honda thing not boats.net. I got used to looking EVERYWHERE on the pages when I worked for a dealer. That hose is under the shift handle heading when it probably should be with the engine cover parts.

Anyway, glad you found the problem. That hose should only be routed a specific way or it will tear like that or get pinched closed and possibly burst after installing the side cover. It MUST go from block then through the hole in the splash tray and out to the cover. Proper routing will let it work as it should.

The hose needs to be refreshed every few seasons as it hardens and will start trapping small debris and make you think you have cooling flow problems.

Good luck!
 
Fogot to say the tube is in stock at boats.net and is $3.12 + shipping and tax (I think)
The info is in the link I sent.
Cheers!
 
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