Old outboard (15hp Johnson) rehab

Share tips, suggest or request changes, anything that does not fit in the other categories.
Online
User avatar
Netpackrat
Very Active Poster
Very Active Poster
Posts: 1034
Joined: Thu Sep 14, 2017 1:35 am
Location: Anchorage, AK

Old outboard (15hp Johnson) rehab

Post by Netpackrat »

Here is the unit in question:

Image

Image

Data plate says it is a 1983 model, which is consistent with my memory of when my dad originally bought it. We ran this on a 12' Achilles inflatable that we used as a river skiff and fishing boat up through the season before my dad passed in early 2000. I've run it a few times (my role on the boat was anchor guy), but was never involved in the maintenance. In 2002 I had the local outboard repair shop in my hometown give it a winterization servicing, then I packed it up in a crate until such time as I needed it again (the inflatable boat was basically all used up by then, and is long gone).

I hadn't planned on it sitting for quite so long, but having just purchased a property that can only be accessed by boat or aircraft, and needing a boat with longer legs than my canoe or D5, I finally pulled it out of the crate yesterday. I changed the spark plugs, mixed some fuel, and using a 55 gallon drum as a test tank, it fired up on the second pull. My dad definitely took good care of his gear.

I didn't run it long because there was no water coming out of the hole on the back, so I am assuming I will need to replace an impeller somewhere (I had been planning to ask about that anyway). I know I probably need to change the gear oil, and I see a bunch of grease fittings on the motor that almost certainly need to be hit (is there a particular grease I should use, or will the wheel bearing grease I use on my Jeep work?. I have a service manual ordered for it, but in the meantime, is there anything else I should plan on doing to it? I have probably at least a couple of months before the ice on the lakes are gone enough to try crossing, and i have yet to find a boat to put it on.

This is just going to be for an interim boat to use until I have gone out there a few times, and have a better idea of what I actually need, so I am probably just going to look for a basic 14-16 foot Jon Boat. Went to a couple of places today to ask about prices on new ones, and they didn't really have what I was looking for and the prices (as is the case for everything now) ranged from merely high, to ridiculously high (Alaska tax). So, Craigslist will probably be my friend and as much as I don't want to have anything to do with the Devil's Database, I am probably going to make a fake account so I can get access to Facebook Marketplace since it seems like that's where a lot of used stuff is being sold these days. Building my own unfortunately out of the question... Maybe if I already had all of the materials on hand, and was willing to cut ALL of the corners and not care what it looks like at all, but the lead time on getting the materials here makes it a no-go in the time that I have left before the ice goes out. Possibly for the permanent boat I will build.

Online
User avatar
Netpackrat
Very Active Poster
Very Active Poster
Posts: 1034
Joined: Thu Sep 14, 2017 1:35 am
Location: Anchorage, AK

Re: Old outboard (15hp Johnson) rehab

Post by Netpackrat »


pee wee
Very Active Poster
Very Active Poster
Posts: 2287
Joined: Sun May 01, 2011 8:29 am
Location: Georgia

Re: Old outboard (15hp Johnson) rehab

Post by pee wee »

You might not need to replace the housing, but you won't know until you open it up.
Hank

jbo_c
Very Active Poster
Very Active Poster
Posts: 1049
Joined: Sat Jun 30, 2007 8:51 pm
Location: Gainesville, GA

Re: Old outboard (15hp Johnson) rehab

Post by jbo_c »

Definitely need a new impeller(though that may not be why it wasn’t “peeing”). If they did good work, probably doesn’t need anything else. Won’t hurt to change the lube in the foot, but probably not even that is necessary.

Jbo

Fuzz
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 8940
Joined: Tue Aug 02, 2011 4:23 am
Location: Kasilof, Alaska

Re: Old outboard (15hp Johnson) rehab

Post by Fuzz »

Those outboards and the 30hp triple Yamaha are two of the best two strokes ever made. Just a ton of power for their weight. As for changing out the water pump it is no big deal. Hardest part may be getting the leg apart.

User avatar
cape man
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 8283
Joined: Sun Jan 20, 2008 12:02 pm
Location: Lithia, Florida

Re: Old outboard (15hp Johnson) rehab

Post by cape man »

Drive it down to Fuzz. Bet he'll help if you ask nice...
The world always seems brighter when you've just made something that wasn't there before - Neil Gaiman

Online
User avatar
Netpackrat
Very Active Poster
Very Active Poster
Posts: 1034
Joined: Thu Sep 14, 2017 1:35 am
Location: Anchorage, AK

Re: Old outboard (15hp Johnson) rehab

Post by Netpackrat »

Thanks for the tips. I found a boat to use with it... Yesterday I went into Dewey's Cook Inlet, which I had driven by a bunch of times but never gone in, expecting it to be a waste of time. I ended up leaving with a deposit on a 14' Marlon jon boat, which I will hopefully pick up next week. It should be just the right size for the motor and the price seemed pretty reasonable, especially compared to what I saw elsewhere.

I also managed to stumble across the contact information for the people who have the barge service on the lake, so I just need to get ahold of them and find out their rates for moving materials and equipment across. My impeller kit should be here Monday or so, and the shop manual I ordered for the motor came in the other day too.

Online
User avatar
Netpackrat
Very Active Poster
Very Active Poster
Posts: 1034
Joined: Thu Sep 14, 2017 1:35 am
Location: Anchorage, AK

Re: Old outboard (15hp Johnson) rehab

Post by Netpackrat »

Somebody just shoot me... Got the impeller kit, got the manual, trying to follow it. This manual is horrible. As an A&P mechanic, I spend a large portion of my workday following manuals, but this one is just bad... Jumps around between every motor they made over a 26 year period. Anyway, I read the dire warnings not to let the driveshaft get pulled out, because the lower unit will then need to be disassembled to realign the pinion gear. Got the lower unit out, disassembled the water pump, and as I am cleaning the drive shaft, before I realized it was happening there was enough drag from the rag I was using, for it to pull out several inches. Immediately pushed it back in amid much cursing neither of which did any good. Operating the shift rod, I can get it to go into reverse but not forward. I assume I am going to need a lower unit rebuild kit, and also that I will wish I had removed the prop when I started.

In other news, the impeller wasn't missing any pieces so at least I don't have to worry about them being where they aren't supposed to be. The grommet for the water tube interface was kind of ugly so maybe that was a blockage, but I would be interested in hearing what some of the other possible causes of no water output might be.

Picked up the boat last week so that's at least good. It's kind of an ice boat right now since we got hit by another blast of winter. It's supposed to be better this week. Going to try like crazy to just make it work with my existing 16' flatbed trailer (going to get a sheet of teflon for the back of the trailer or maybe some rollers to slide it over) because I really don't want another trailer in my life right now.

Edit to add; I had been holding off draining the oil until I had the water pump replaced and ops checked, figured I would do that last. Since it looks like it all has to come apart no matter what, drained the oil. It was pretty ugly, looked like it had been there a while, but at least there was no water in it.

jbo_c
Very Active Poster
Very Active Poster
Posts: 1049
Joined: Sat Jun 30, 2007 8:51 pm
Location: Gainesville, GA

Re: Old outboard (15hp Johnson) rehab

Post by jbo_c »

Around here, a very common issue for “no pee” is a dirt dobber nest in one end or the other. Easily fixed with a piece of wire and some diligent flushing.

Corrosion in the internal pathways is a possibility, particularly if it was used in salt water, but I have to admit, I’ve been spoiled and not run into that problem.

Could have been mid-alignment of the tube.

Jbo

Online
User avatar
Netpackrat
Very Active Poster
Very Active Poster
Posts: 1034
Joined: Thu Sep 14, 2017 1:35 am
Location: Anchorage, AK

Re: Old outboard (15hp Johnson) rehab

Post by Netpackrat »

Dirt daubers aren't a thing here, but I will for sure flush and check for blockage.

Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests