1972 Johnson 50 HP

[cretus]

Hi guys. I've been reading pages and pages about this motor, but havent really found anything that is my problem.
Heres what I've got. I ended up with a 16 foot boat with the 50 hp on the back for $150.00. The problem is the back end of the boat sank and caused a light rust on the cylinder walls which made the motor apper to be locked up. This being the main reason it was so cheap. A little PB blaster and a few minutes of rocking the flywheel and she broke free. Now if I could just get it to run. I gave it a shot of starting fluid and it fired right up. I dont think it is getting any fuel or maybe the carbs are clogged. Any thoughts on how to get her running would be greatly appreciated. I'm good with motors, but dont know a thing about an outboard.

 

[steelespike]

Re: 1972 Johnson 50 HP

First get yourself a service manual; reprint factory manuals are available right here at iboats. You could also check the library for an after market manual.
Go through the fuel system from tank to carb most likely gummed up from sitting plus water intrusion problems.System is the same idea as a car;tank-fuelpump-carb.
Fuel pump is pulsed by pressure pulses from the crankcase,Carb is basic just
be sure you clean it good all passages and jets. Factory tank vent opens when you
connect the fuel line.others have a little vent knob on the cap.Do you know the normal starting procedure?It uses a self generating cd ignition system don't mess with it without a manual including checking for apark.

 

[cretus]

Re: 1972 Johnson 50 HP

Thanks. I'll look for a manual.

 

[cretus]

Re: 1972 Johnson 50 HP

Well i did get the carb bowls drained and they were both full of rusty water. I sprayed them with carb cleaner and pumped gas through them till the fluid was straight gas. Of course gas was running in the engine cowl and down the side of the motor into the drum of water I was using to cool the motor. I tried to cramk the motor after putting the carbs back together and the upper cylinder backfired through the carb a lit all the carb spay and gas on fire which quickly ran down the motor to the drum of floating gas. What a mess. Nothing got burned because the hose was running and I was able to get the motor fire put out quick. The drum and the boot was cooking for a while, but there was no damage.

 

[Daviet]

Re: 1972 Johnson 50 HP

If the carbs were full of rusty water you are probably going to have to remove them and rebuild them using new carb kits. Make sure and clean ALL passages in the carb.

 

[cretus]

Re: 1972 Johnson 50 HP

Alrighty then. I have rebuilt the carbs. Funny thing is all that I needed out of the kit was a few parts. By the way the carbs were full of crap.
I've got them back together and back in the engine. Question is whats a good point to run the needle valves out to to get the boat running.
Question two, Where is the water outlet from the impeller at? I still havent got a manual for the motor, just for the reason of not needing it if it never runs.

 

[coolguy147]

Re: 1972 Johnson 50 HP

while you're changing the water impeller and gear oil. and cleaning the carbs and rebuilding them. plus replacing the fuel lines and checking compression annd checking spark.

you should put tcw-3 oil into the spark plugs holes and rotate the cylinders a few times then appply more then tilt the motor up and apply more. let sit while tilted up. put spark plugs back in.

 

[F_R]

Re: 1972 Johnson 50 HP

I am really surprised the bearings aren't shot in that motor. Or are they??? Your efforts may be futile if you do get it running and it throws a rod.

 

[cretus]

Re: 1972 Johnson 50 HP

We'll find out soon enough

 

[DECK SWABBER 58]

Re: 1972 Johnson 50 HP

OH BOY.

Be sure to post back with your results.