Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 15hp Johnson issues

Posted by glfarnes on 10/30/11 - 9:43 PM
#1

I found a 1980 15 hp Johnson outboard a few years ago and gave the owner a hundred bucks for it. It ran rough but had good compression. I decided to rebuild the carburetor and test run it. It ran very well but it just didn't seem right in the cooling department so the water pump got the next fix. While the lower was off I looked up into the shaft housing and saw this.

http://s1116.photobucket.com/albums/k...hannel.jpg

I found that the rubber part sticking out is a lower exhaust gasket. I'm a little afraid of pulling the whole thing off the power head because this is a salt water motor and there is potential for a lot of problems. Has anyone had any luck using one of the various high heat silicons on the market on a blown out gasket like this?

Edited by Tom W Clark on 10/31/11 - 10:29 AM

Posted by seahorse on 10/31/11 - 4:43 AM
#2

That is the rubber seal between the tuned exhaust pipe and the midsection. That shows the motor has been severely overheated. You have to remove the powerhead from the exhaust housing to replace it. Also the rubber grommet where the copper water tube fastens to the powerhead may be scrunched up and possibly restricting the water flow to the cylinder block.

Edited by seahorse on 10/31/11 - 4:44 AM

Posted by glfarnes on 10/31/11 - 10:06 AM
#3

Thanks, I'll make a trip to the outboard shop today and see what parts are available. It doesn't look like a big job but on these old motors that have run in salt water it can open a can of worms so wish me luck.

Jerry

Posted by glfarnes on 11/10/11 - 7:35 PM
#4

Update. Found that all parts are still available for these little old engines. I checked the compression to see if it was worth proceeding and both cylinders were close to 100 so I pulled it apart. It looks good but three bolts snapped off where the exhaust bolts to the block. I'll be drilling tomorrow and finding out if it's going to be a heli-coil job or not. I've heard that there are better options than Heli-coils but I don't know what they are.

Posted by Gamalot on 11/11/11 - 8:24 AM
#5

Shearing bolts in these older motors is pretty common. For future reference I find that using an impact wrench helps. By impact wrench I mean a spring loaded ratchet device you slap with a hammer. These are commonly found in the motorcycle industry.

If you have the room to insert a helicoil then is it possible to tap the holes to accept a larger bolt?

Posted by glfarnes on 11/11/11 - 9:24 PM
#6

Things didn't work out and due to the difficulty of drilling out the bolts. Two of the bolt bases spun in the bottom of the holes and I couldn't get them out without damaging the block beyond repair. Off to the scrap heap with this one.

Posted by Gamalot on 11/12/11 - 7:07 AM
#7

That's too bad Jerry, Rather than the junk heap why not toss it on CL as a parts only motor for cheap. I am sure there is some local repair guy who could use a few parts from it and it could put you in touch with a fellow who knows his way around motors.

Posted by Mattanza on 11/12/11 - 9:44 AM
#8

part it out on ebay.

Posted by glfarnes on 11/12/11 - 2:48 PM
#9

I live a hundred miles from the nearest road and unless someone here in town wants it shipping prohibits Ebay. I'll probably just give it to the local boat shop. They have a pile of old outboards they part out as they need them.

I did hear of a sleeve type thread repair that I'm trying to find a source for as that seems like it would maybe fill a larger hole than the Heli-coil.

Posted by Joe Kriz on 11/12/11 - 3:02 PM
#10

These are fairly common inserts used to repair block threads and many other uses.
http://www.mcmaster.com/#threaded-ins...ts/=ewnwr9
NOTE: can't bring up the direct link to "Threaded Inserts" so you will have to click on Threaded Inserts Key Locking....

Much, Much, better than helicals........

Edited by Joe Kriz on 11/12/11 - 3:06 PM

Posted by glfarnes on 12/01/11 - 10:37 AM
#11

I had success with the threaded inserts. They come in a multitude of sizes and have been around for many years. I was able to use a 3/8 insert with a 1/4-20 center. The broken nubs of the bolts came out when I drilled the holes out for tapping. I found that the exhaust manifold was a little "off" from the factory and had to pry it into alignment while tightening the bolts. There are a couple of parts missing from the recoil starter so I haven't been able to test run the motor yet, so when they arrive I'll post one last update and let you all know how it runs.

Posted by Gamalot on 12/06/11 - 5:34 AM
#12

I am in a similar quandary and could use some advice. Not BW related but the same situation.

Changing fluids in the rear differential of my Polaris RZR and the drain plug came out with the threads from the housing. The plug itself is fine and 3/8 by 24 NF threads.

I am going to need an insert but don't know what size to buy or how these inserts work. Are they slightly larger and designed to screw right in to the existing threads that are left or do I have to drill and tap the case before installing the insert? I also don't know if the insert will allow me to re use the existing 3/8 X 24 drain plug of if I will need a larger one.

What I do know is I have plenty of room where the drain is to drill and tap for a larger plug. The problem is in the removal of the entire rear differential, wheels, axles, and just about every other part to get to where I can do the drilling and tapping. If these inserts just screw in to the existing buggered threads it sure will make my fix easier.

Posted by glfarnes on 12/21/11 - 10:38 PM
#13

The weather finally warmed up enough to fire this little outboard up. I purchased a new hose for the kicker can due to the old one leaking like a sieve and have found that the new one leaks just as bad. I got it pumped up with considerable gas flowing into the garbage can I was using as a test tank. She fired right up and ran for about twenty seconds and quit with no water pumping from the pee hose and none coming out the exhaust. I fired it back up and revved it a little and water began flowing as it should. The engine started choking for gas and I had to keep pumping the bulb to keep it going but it quit again. I restarted and no cooling water again so not sure what's going on at this point so I'm putting her away until spring. I'm moving and just don't have the time to work on it.

The hose I'm using is an OEM Johnson but it must be a new Chinese model.