New to me, older Johnson 15hp

[Busbey]

Re: New to me, older Johnson 15hp

here are the pics i guess that didnt work earlier in the post.

jrs_diesel, please confirm we/you are on the same page. i am intertested in looking for a few things locally and want to be sure i get the proper parts. . .

see this metal plate? shouldnt a thermostat or something go here? when it was running there was a little bit of water coming out of this, the RTV seal the guy put on i guess isnt holding anymore. . please help me identify this.

 

[bob johnson]

Re: New to me, older Johnson 15hp

So, definitely a late 86 (like mine) or newer. Sounds like it in the range of late 86 to 89. 90 is about when they changed the kill switch to the side of the tiller handle instead of the very end.

That 1 inch circle is where the kill switch used to be on motors early 86 and older. Mine has the hole too, just with a factory plug closing it off.

I'd get a new knob for your low speed mixture and soon. Otherwise the only way to adjust the idle mixture is to remove the top of the air box (silencer) and adjust the screw either by hand or with a set of pliers.

Seems like someone installed an aftermarket kill switch on yours.

I have a 1990 johnson 2 stroke 15 hp and my kill switch is on the very end of the tiller handle, not the side...and i can easily read my model number so i KNOW its a 1990.
bob

 

[Busbey]

Re: New to me, older Johnson 15hp

Guys, if there is no model number on the Welsh Plug or the side of the Transom mount, is there no way to ever know for sure?

Also, look closely at my Welsh plug and this picture above. its almost like i am missing the actual piece. mine sits much lower..??

one more thing, see the piece that is all the way to the back, with 3 bolts holding it on... whats that piece? thats where mind has a piece of metal there with only 1 screw

 

[jrs_diesel]

Re: New to me, older Johnson 15hp

That plate should not be there. That looks like its holding the thermostat in. Since your thermostat is on the upper part of the cylinder head, it's an 87-90. 86 and older had the thermostat lower in the head and more difficult to replace.

Looks like someone before you lost or broke the thermostat cover and stuck that plate there. The proper cover has three bolts holding it on.

That kill switch isn't factory either. It also appears that your welch plug was damaged somehow.

 

[bob johnson]

Re: New to me, older Johnson 15hp

Guys, if there is no model number on the Welsh Plug or the side of the Transom mount, is there no way to ever know for sure?

Also, look closely at my Welsh plug and this picture above. its almost like i am missing the actual piece. mine sits much lower..??

one more thing, see the piece that is all the way to the back, with 3 bolts holding it on... whats that piece? thats where mind has a piece of metal there with only 1 screw

it is highly likely that motor has been apart before, maybe rebuilt maybe not thus the aluminum plugg has been replaced....the three bolt cover is the thermostat cover...you should get one...they may have stripped the threads in the upper two holes thus they made up a replacement cover out of aluminum....if it doesnt leak its no big deal..

why cant you read the tag on the stern bracket that mounts to the boat for the model number????

what is the problem you are having with the motor??? if any??

bob

 

[jrs_diesel]

Re: New to me, older Johnson 15hp

Here's what you are looking for on the tag (if there is one). It's usually on the transom bracket on the tiller handle side.


Here's what the welch plug should look like:


I'd hate to give some more bad news, but you may have a 9.9 HP. They were the same engine but with different carbs (and some other parts depending on year). No way of knowing without a model or serial number what it was built as.

One way to find out is to pull the carb and look down the bore. Get a 5/8" and a 7/8" socket. You can use the socket to compare the bore size. The 9.9 HP carb has a 5/8 bore (.625 inch), and the 15 HP has a 7/8" bore (.875 inch).

The reason I mention that is that my engine (an 86 9.9 Johnson), has a 15 HP hood on it. But the model numbers and carb bore indicate that mine is a 9.9 HP.

Let us know what you find.

 

[Busbey]

Re: New to me, older Johnson 15hp

referring to this picture, the cord rewind piece is bent and popped out twice trying to start it. you can see in this pic how it sits. the clip also comes off when cranking. the one to the left (dead center of this picture) it sat for a year and i may need a carb rebuilt kit, not sure yet. the kill switch i am ok with. the knob for the low idle mixture and the thermostat cover are needed. also i need to get 2 new knobs that screw this onto the transom. want to make sure i get the proper size or whatever.

i cant just order something and hope it fits, this is why i need to find out what i need to order for

in this second picture, to the right of the blue square, there is a plastic box. this isnt on mine, but i have it. i guess i just need some screws to put it on. what is this box called?

 

[Busbey]

Re: New to me, older Johnson 15hp

Here's what you are looking for on the tag (if there is one). It's usually on the transom bracket on the tiller handle side.
View attachment 99668

Here's what the welch plug should look like:
View attachment 99669


I'd hate to give some more bad news, but you may have a 9.9 HP. They were the same engine but with different carbs (and some other parts depending on year). No way of knowing without a model or serial number what it was built as.

One way to find out is to pull the carb and look down the bore. Get a 5/8" and a 7/8" socket. You can use the socket to compare the bore size. The 9.9 HP carb has a 5/8 bore (.625 inch), and the 15 HP has a 7/8" bore (.875 inch).

The reason I mention that is that my engine (an 86 9.9 Johnson), has a 15 HP hood on it. But the model numbers and carb bore indicate that mine is a 9.9 HP.

Let us know what you find.

both of those are missing. on the back of the motor, i can see a 15 stamped on something. i think it is on the tiller side of where the thermostat is. i hope this means i have a 15hp.... ...

 

[jrs_diesel]

Re: New to me, older Johnson 15hp

That doesn't tell you anything for certain. OMC didn't put model or HP information there. You'll have to pull the carb to know for sure what you have.

That plastic box that you don't have is the air box that sits on the carb (also referred to as a silencer).

The starters are pretty simple to take apart and repair. Check out that site I linked you to on the first page. Tons of great repair info on these engines.

 

[bob johnson]

Re: New to me, older Johnson 15hp

busbey, you really need to look over this website for a few hours....it will really help..it is a fantastic page for anyone having a 9.9 or 15 hp OMC product for the years they cover

http://www.sschapterpsa.com/ramblings/Johnson 9.9_15.htm


bob

 

[AEROCOOK]

Re: New to me, older Johnson 15hp

If it's the original cowl it's a 1987 or 1988... 1986 had different graphics and so did 1989

 

[Busbey]

Re: New to me, older Johnson 15hp

busbey, you really need to look over this website for a few hours....it will really help..it is a fantastic page for anyone having a 9.9 or 15 hp OMC product for the years they cover

http://www.sschapterpsa.com/ramblings/Johnson 9.9_15.htm


bob

just printed all 33 pages

 

[AEROCOOK]

Re: New to me, older Johnson 15hp

BTW get rid of that 100/1 decal by the fuel hose, these motors should run at 50/1. Hopefully it hasn't run at 100/1 it's entire life.

 

[Busbey]

Re: New to me, older Johnson 15hp

yeah i noticed that too.

i plan on taking this to my buddy tomorrow and seeing what he can do with it. i would like to get it on the water Sunday morning if at all possible. but if he suggests not to, of course, i will have to use my 6hp Montgomery Ward to get around.

 

[Busbey]

Re: New to me, older Johnson 15hp

I was just thinking... Sometimes it gets me into trouble..

What's you guys thoughts on getting some sort of extension for my transom to allow me 5" higher for mounting this motor. Versus finding buying and installing a short shaft. This way I could have the best of both worlds if I get a 2nd boat and need a long shaft.

 

[bob johnson]

Re: New to me, older Johnson 15hp

I was just thinking... Sometimes it gets me into trouble..

What's you guys thoughts on getting some sort of extension for my transom to allow me 5" higher for mounting this motor. Versus finding buying and installing a short shaft. This way I could have the best of both worlds if I get a 2nd boat and need a long shaft.

nothing new...just make sure the over lap onto the present transom is sufficient... to carry the stiffness up to your new height...

an aluminum plate is nice, but expensive

if you dont mind wood on your boat( not me I hate it)
then you could fashion something.....good luck

bob