# johnson 15 horse water exit?



## doc1976 (Mar 19, 2017)

where exactly is the water supposed to exit on an 85 johnson 15 horse? Im not sure if mine is pumping water correctly.


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## stinkfoot (Mar 19, 2017)

My '76 one doesn't have a tell-tale. Does yours have a pee-hole? Underneath the powerhead casing usually.


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## doc1976 (Mar 19, 2017)

yes it has the pee hole, coming out there fine, cold water. It also comes out in the two places the picture shows. the small hole stays cold and flows solid, the second spot has only a little water coming out it seems but is warm.


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## wmk0002 (Mar 20, 2017)

The small hole is simply a drain hole for the entire leg for when you trailer the boat to keep from having any freeze in there.

The series of holes above the anti-ventilation plate are exhaust gas holes, however, cooling water also exits there too when you are running it on muffs. It is warm because it has passed through the thermostat and powerhead where as the pee hole that comes out the side is tapped into the the cooling water prior to the thermostat . Same happens through the prop as well as the exhaust port on the upper rear of the leg just under the cowling in terms of outputting warm water with the exhaust.


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## doc1976 (Mar 20, 2017)

wmk0002 said:


> The small hole is simply a drain hole for the entire leg for when you trailer the boat to keep from having any freeze in there.
> 
> The series of holes above the anti-ventilation plate are exhaust gas holes, however, cooling water also exits there too when you are running it on muffs. It is warm because it has passed through the thermostat and powerhead where as the pee hole that comes out the side is tapped into the the cooling water prior to the thermostat . Same happens through the prop as well as the exhaust port on the upper rear of the leg just under the cowling in terms of outputting warm water with the exhaust.



well I have something not quite right then. I have only a tiny bit of water coming out of the holes above the anti-ventilation plate, no water from the prop or the exhaust port, a good stream from the pee hole, and a stream with enough pressure to shoot 2 or 3 feet from the drain hole. this is the case when the muffs are on, cant figure out a way to see where water is exiting if i run it in a tub.


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## Crazyboat (Mar 20, 2017)

On my old 74' The pee water as it were came out on the rear of the shaft just under (maybe 6") where the hood met the leg. It would spit or spray water out, never a tell tale stream.

Hope I'm explaining this in a way you can visualize.


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## doc1976 (Mar 20, 2017)

starting to sound like Ive got a restriction somewhere. guess I will start at the bottom and work my way up. I will start by pulling the t stat and force water/air through the water pickup tube from the pump and see if there is flow.


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## stinkfoot (Mar 20, 2017)

Crazyboat said:


> On my old 74' The pee water as it were came out on the rear of the shaft just under (maybe 6") where the hood met the leg. It would spit or spray water out, never a tell tale stream.
> 
> Hope I'm explaining this in a way you can visualize.


 Yeah, that's the exhaust, same with mine. I'd pull the lower unit off and check there are no busted up impeller pieces in the water tube. Did you change the impeller already?


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## Pappy (Mar 20, 2017)

On a 1985 you have an overboard indicator. Located on the stbd side of the lower cowling just about even with the spark plugs. Take a toothpick or something and shove up in there or use compressed air to blow it out before someone has you disassembling your engine. If you have a set of muffs that have the plastic arms throw them as far as you can throw them. Get a set with the steel arms.


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## stinkfoot (Mar 20, 2017)

He already said it is peeing well, Pappy.


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## Pappy (Mar 20, 2017)

I see where he said that now. 
The small hole in the front above your cav plate is simply there to prevent freeze damage. The other holes are there to vent water when the thermostat opens. 
From the sound of what you are seeing I would say you have a good cooling system. The cylinder head at the top should be running around 135f at idle and slightly above. No way to check? place your hand on it once warmed up. You should be able to hold your hand on it for around 5-6 seconds before it becomes uncomfortable. Once on plane the engine should cool down from there. No number because it varies with water temp in the body of water you are in. 
Edit: If the engine has never been serviced or had an impeller or a pump by all means do it. Way beyond overdue at this point.


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## doc1976 (Mar 20, 2017)

I put in a new water pump, and had to clean the overboard indicator outlet and hose due to being clogged. I ran the motor with muffs for a good 15 minutes maybe a few more more, and the motor never even got warm enough to be uncomfortable. that is what has me puzzled. essentially there are 3 places that should normally allow exhaust and water to exit, and I'm not really getting water out of any of them.


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## doc1976 (Mar 20, 2017)

so just for the sake of conversation, how/why would water be coming out the drain hole with such force only when running?


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## Sinkingfast (Mar 20, 2017)

doc1976 said:


> so just for the sake of conversation, how/why would water be coming out the drain hole with such force only when running?



So..when the motor is not running there is no water being pumped..with muffs and not running I dont think water will make it there. 

I didnt read all the post but I think that hole on the front of the lower drains the shift shaft chamber and the lower. Some water makes its way to the drain hole when motor is running. none when motor is not running. The holes on the back of the lower is where most of the water leaves the motor..so same reason here.

If that is what you are referring to.

Edit..I think I might have read your post wrong but anyway..The water tube has a hole in it that sprays water into the mid all the time when its running. Cold or hot.


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## Pappy (Mar 20, 2017)

There is not a lot of water going through your engine at idle. There is no reason other than exhaust pressure from the tuner for the front hole to have pressure. Worry more if that hole does not flow water. If your engine is cooling at idle and has run that long on the hose you should be good to go. Sinkingfast has it right on the water supply tube hole. Its spraying water in the inside of the exhaust housing all the time. You may not like the answer but I really think you are looking for a problem when none exists. I gave you the temps to look for, why not just go and run it and check.


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## Sinkingfast (Mar 20, 2017)

Check out leeroy's outboard site. There is a cooling system diagram somewhere there. If you hadn't yet that is...


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## doc1976 (Mar 20, 2017)

yeah found leeroys site, lots of good info there. I would not be nearly as concerned about things if I was getting water out of the correct places(prop, exhaust relief. etc) which I should be getting. the boat is not quite ready for the water yet, so It will have to wait for a test on the water. I guess I will just wait and see.


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## Pappy (Mar 20, 2017)

There are youtube videos of other 15hp engines running on the hose. Don't see much coming out the prop on either of these and for all of the engines I have run over the years there simply is not much coming out there on a 15hp. 

https://www.youtube.com/watch?v=rjlxAanNl6Q

https://www.youtube.com/watch?v=Dr3yqLpIo10


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## stinkfoot (Mar 20, 2017)

I think Pappy has it right. If you have a blockage the head will be too hot to touch in short order once you run it on the lake.


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## timsmcm (Mar 21, 2017)

Did you actually look to see if there was a thermostat in the motor? It is hard to get to. I know some people take them out and run without them and they will never warm up. You can get away without running a thermostat in the summer with hot water in the lakes but when it gets colder you need the thermostat. I have an 85 15hp evinrude. No water comes out the hole under the cowling in the rear. Big huge stream out the small round hole in the rear of the foot, a little comes out the holes above and the prop. Sounds like you have a motor with no thermostat in it.


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## doc1976 (Mar 21, 2017)

I was wondering about a PO removing the t stat because it was not getting warm at all plus a little rough at idle to suggest not getting up to temp. I am used to a much bigger motor and when you hook the hose up you get water out the prop and other relief areas in a hurry and with some noticeable flow. may just be expecting too much from this little guy. I plan to get a no contact thermometer and run in a tank in the next couple days to get a more accurate idea of what is happening. If it doesn't warm up or gets too hot then I will know better where to go next. thanks everyone for all the help its greatly appreciated. will post results soon


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## Pappy (Mar 21, 2017)

Thermostat is needed for three reasons. 
First reason is for a good smooth idle (compared to no thermo).
Second reason is to keep from making water inside the engine while in colder water. 
Third reason is premature wear of the pistons. Hot piston/cold sleeve equals an increased rate of wear. 
The information listed in another post is the old wives tale stuff left over from a bygone era.


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## wmk0002 (Mar 21, 2017)

doc1976 said:


> wmk0002 said:
> 
> 
> > The small hole is simply a drain hole for the entire leg for when you trailer the boat to keep from having any freeze in there.
> ...



FWIW, you may actually not see water out of the exhaust hole on the leg. I have a 1982 9.9hp and 15hp and the 9.9 will spray water from that port when the thermostat opens, however, the 15hp won't. This is because the 15hp has a longer exhaust water tube coming out of the powerhead than the 9.9 does for whatever reason....long enough that it extends past the opening. Now, I'm not sure if all 15hp ones are like this or maybe a previous owner used the wrong part or what but wanted to mention it anyways.


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## Pappy (Mar 21, 2017)

Take a look at parts diagrams again.....
The 9.9 has a full length exhaust tube. The 15hp for most of the model years has a short exhaust tuner.


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## wmk0002 (Mar 21, 2017)

Pappy said:


> Take a look at parts diagrams again.....
> The 9.9 has a full length exhaust tube. The 15hp for most of the model years has a short exhaust tuner.



I was just referring to the outlet water tube.


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## Sinkingfast (Mar 21, 2017)

The 9.9 had a wet leg...the mid fills with water and spills over the passage inside the rear of the mid. No hole in water tube from pump. Tuned length exhaust.
The 15 used what I call a folded horn exhaust like on my 550sx standup ski. The mid does not fill up with water. Most dumps down the rear passage with a short tube. Has hole in water tube from pump to cool the mid. Tuned to a narrow rpm range since there is no reverse cone, just a target piece at the end of the megaphone.


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## doc1976 (Mar 21, 2017)

okay so I got the motor running in a drum today used a 55 gal drum so it would hold plenty of water and not let the water warm up much. ran the motor for 40 minutes mostly at idle with a few revs here and there. the hottest the head got at the top was 99.5 degrees. the head by the plugs saw 104, the water cover over the t stat got to 98, and the side of the crankcase right at the seam got to 106. So i am led to believe either the thermostat is stuck in the open position or there is no thermostat at all. 

on a side note, the exhaust relief hole under the cowl latch was spitting out water and exhaust just like the ones in the videos so I guess the motor is pumping water fine.


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## doc1976 (Mar 22, 2017)

thanks everyone for your help and suggestions.


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## CMOS (Mar 24, 2017)

Pappy says, "why not just go and run it and check?"


Gotta love words of wisdom from an expert. :mrgreen: 


CMOS


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## doc1976 (Apr 23, 2017)

so to follow up with this post, if anyone cares or can learn from it, I got the motor repaired. The issue with the motor not warming up was due to the spring that holds the T-stat in place being extremely weak. It did not appear to be holding the stat down so water was getting past without it opening. plus the stat was opening way too early. Also found the wrong grommet was used for the water tube at the pump, as well as the exit water tube being the wrong part, someone replaced it with a pre-85 part. the head came off and was cleaned and surfaced, as was the water cover. replaced seals and o ring on the lower crankshaft head, as well as all gaskets and seals that were removed. Got it running in the tub the other day, and it warmed right up to temp and maintained temp just like it should. so It seems as though all is well with it and as soon as my transom is finished, I can get it out and see how she runs. thanks again for all the help.


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## CMOS (Apr 24, 2017)

Thanks for the update.


CMOS


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