9.5 Johnson Overhaul advice

[Makersmarc]

I have a 9R-73B Johnson 9.5 that I bought to use on my personal boat I use exploring rivers and creeks looking for wildlife. Cosmetically it's in great shape. I've rebuilt the carb and put in new points/condensers. I ran it on the lake on my 12' aluminum boat and it had good power. The problem is that it's a bear to start. In the test barrel, I use a 1/2" drill and socket on the flywheel to start it. After about 15-20 seconds of cranking it will start and then run okay. Once it warms up it runs smooth. However, when I am out on the water (and have to use the rope) it is impossible to start.

The compressions are both 41# on a warmed-up engine. I have resigned myself to the fact that I will have to overhaul this engine. I have used the Sea Foam treatment to try to de-carbon the rings, no joy.

Before I start breaking it down I would like to know what I should anticipate as far as parts replacement. Besides the usual stuff (gaskets) what is the best practice for an overhaul? I am inclined to just put in new pistons and rings and reuse the wrist pins et cetera provided everything fits together within a reasonable tolerance.

Also, should I need to have the cylinders rebored is there a good source for 0.020 oversized pistons?

 

[F_R]

Those motors should start very easy. 41# is way too low. You will have to tear it down or inspection. Could be as simple as a head gasket.

 

[racerone]

Some more trouble shooting is required !-----Not sure if you can get O /.S pistons at this time.-----Pull the cylinder head off before any more $ is spent.----Those motors will test your patience if you have to tear it down to the point of piston / ring replacement.

 

[Scott Danforth]

that motor is nearly 45 years old. you should be able to buy another good running 10hp johnyrude that is only about 20 years old in your neck of the woods for under the cost to rebuild what you have.

 

[Makersmarc]

that motor is nearly 45 years old. you should be able to buy another good running 10hp johnyrude that is only about 20 years old in your neck of the woods for under the cost to rebuild what you have.

Yeah, that's true for sure. For me it's not just about having a usable motor, I enjoy fixing stuff. I figure that I'll learn something along the way if I don't go broke lol.

 

[Scott Danforth]

while I can appreciate that. I view a fishing motor as a tool to go out and go fishing. my last purchase was a 20hp motor for $100. if it needs more than an impeller and carb kit, it will get parted out on ebay and i will buy another $100 motor

 

[tpenfield]

You can tear it apart in order to find the cause of the low compression. But keep in mind that the cost and agony of fixing it may not be worthwhile as compared to getting a newer engine.

The oversized pistons ( 0.030 over) are listed as "unavailable". If you are lucky, then maybe just the ring set @ about $45 would be needed, plus the gasket set ($100) and bearings. ( $88 each )

It could start to add up . . .

 

[oldboat1]

Or....pull and replace the head gasket, checking for obvious issues when the head is off -- maybe some carbon clean up if that's necessary. Then continue to use your 24V drill for starting (duct tape the socket in place to keep from losing it into the lake). Be on the lookout for well-priced 9.9, maybe mid-80s model. (Actually, I would also be looking for a 10 from the mid 50s or so as well -- great motors that run forever. Price likely quite a bit lower.)

 

[rolmops]

Now that a lot of people are replacing their 2 strokes to 4 strokes specially on sailing boats you can find the old 9.9 2 bangers for under $400. But there is a lot of spare parts and new old stock at considerably lower prices than the ones mentioned before. Here in Rochester, NY close to the Finger Lakes and Lake Ontario there are a lot of spare parts available.

 

[Inflatablefun]

Just to throw my 2 cents in there, I certainly agree with Scott Danforth's advice and adhere by it myself. Plenty of dirt cheap motors out there (and more recent than 1973 and the outdated magnetos)!
As an added note, since your main goal on the water is observing wildlife (love it too), have you considered trolling motors for quietness?

 

[Crosbyman]

well my 9.5 (9622a) is a hard starter also.

I haven't ventured to overall the carb because once started it purs and runs all day on 65 pounds .

that said, have you tried another meter just in case...
it won't help you to start it but you will have a different opinion of it

to ease my shoulder pains I pop the hood and give it a shot of carb cleaner and...vrooomm off I go. (I know carb cleaner is bad)

my point here is we both have notorious low compression motors with an identical "first go" starting problem and runs good once started...

to keep your drill out the lake and you ... try a shot of carb cleaner or... WD40 (which also works) a less complex and expensive solution than a rebuild

paid 50$ for mine and satisfied 100%

 

[racerone]

I got one for free couple of years ago.----It stopped and was seized.----Turns out a screw came loose under the flywheel.------Trouble shooting and inspection needs to be done.----Those motors will start in 2 or 3 pulls when properly tuned./

 

[Crosbyman]

got myself one of the alias FR now Richard White OMC timing tools ... that ismy next Spring thing when the white stuff goes and I can access my garage

maybe a timing tune up will help but I am not opening that 9.5 carb if it runs good

my nice $60..... reworked 6r74c is just waiting to take it's place so I have lots of spares

here is a picture of a 6hp just like mine

 

[thatone123]

I think these outboards do not start quite as easy as a over the flywheel recoil starter. They do not produce the higher torque and speed of the over the flywheel starter... I like these old motors and the sound reminds me of a Harley Davidson. They use more gas then the later 9.9/15 but are a inch shorter than any other outboard and great for shallow water. Properly tuned they start good and run fine.

 

[TN-25]

Those old turtlebacks, some people hate them and some people love them. It is almost as if you luck into a motor that just always seems to run well vs. one that is never quite right. Dad bought a '65 new and it ran like a champ for decades. He gave it to a friend so I managed to find a nice '67 from an elderly gentleman. There are a lot of features on those motors, shallow angle drive, numerous tiller arm stops, low height, easy to carry, very quirky to work on. Also they weren't designed for remote controls but you can still buy an OEM kit with the steering bracket, cable stops, everything you need to replicate your own Rube Golberg contraption.

 

[thatone123]

I think those old 6 hp are almost as good as the 9.9/15's. I keep a 6 wrapped in garbage bags hidden out in the bush for emergency. I live in the far North. Even blow a head gasket in the North Woods? Cut a piece of Birch bark, works like a charm.

 

[Stumpalump]

I think those old 6 hp are almost as good as the 9.9/15's. I keep a 6 wrapped in garbage bags hidden out in the bush for emergency. I live in the far North. Even blow a head gasket in the North Woods? Cut a piece of Birch bark, works like a charm.

I sold an old 6 today. They are great. The really old 3 hp and 4's are a good zombie apocalypse motor as well. I'm doing a resto on a 4 hp folding Evinrude now. The 9.5's are always good to me as well. If I were the OP I'd just clean the carb. It could just be lean on the slow side. Peek at the reeds for complete closing while your at it. Crap can fall in them and hold them open. If that don't get it then Emery the cylinder and throw rings in it. I'd rather have a nice running 9.5 than a 9.9/15 because they are just so well built and feature packed. The 9.5 is known to test low on compression and still being a good runner so I'd make sure the above is good before tearing into it.