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1974 50HP mod# 50ESL74M PROBLEM!

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Gluk101

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Hello, I'm new to this website, but already loving it. I have a 1974 50HP Johnson and it won't start. When I turn the key the starter turns and turns, tries to start but wont start. We bought it at the garage sale when we bough it, it will start now and then, works fine until you turn it off that it may or may not start. One period it would start every time, so we took out to the water. it wouldn't start for like an hour, then it started, and OMG it ran nice.... until about 10 minutes later when it staled out and wouldn't start again. When I got home i took the spark plugs out, they have a nice spark i also cleaned them to make sure there is no dirt, screw them back in. check the fuel filter, clean. Checked all the wiring, all seems o.k. but it just wont start. tried and tried after which I drained my battery, recharged it overnight and next day it started just fine, worked for about 20 min just fine, turned it off when to grab a lunch. hour later it wont start again, it went on and off like that till i drained my battery again. Next day tried again and it wont start at all, tried and tried it just wont start anymore, starter turns the big disc(not sure the name of it) turns as well but wont start. I don't know what to do, please help.
 
The starter needs to turn the motor quickly in order for the magneto ignition to work.-----------------I would inspect the starter.-----------These starters are easily damaged by excessive cranking.
 
Thanks for replying, I'm not sure how fast it has to spin, I took a few videos, can you please check and see if it spins fast enough??
On the second video my battery started to die out.


 
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If the battery is dying / dies then there won,t be any spark.-----Those starters are easy to inspect / repair / install new brushes.------I put new brushes in them all the time $5.00 a set.----------Leave spark plugs in , use spark checker set at 7/16" gap , if it turns fast enough it will jump that gap.
 
At times, I can start such an engine with a pull rope. It doesn't take much crank to start a motor if compression, sparks, fuel/air are all there. Don't try to start a motor by draining a battery trying. Try to sqirt some mixed fuel directly into the carbs and start to see if it catches fire. If it does, it's an insufficient fuel problem or way over mixed. Does the choke work? Manually pull it to shut the choke flies to see it it helps start. Proper mixture, sufficient fuel, consistent sparks will have it start right up in a full quick turn.
When cranking, does gas come flushing back out of the carbs? If so, flooded. Result of stuck choke/choke stay on, ruptured fuel pump diaphragm, etc...also either weak/intermittent solenoid, week battery or weak starter (least likely) all leak to slow cranking, leading to weak sparks, check for corrosion on battery terminals and ensure all connections are good. Marine starter motors do go out but rarely.
Good luck
 
I have to agree with racer on that..those starters don't take much to burn out from excessive cranking..it just eats the brushes right off. I had the same trouble with my 72 50 'Rude...still don't know why it wouldn't start at times, but this year, after sitting for 2 years, it fired right up. Mine gave me a hard time at cold starts, usually fired when warm. It would start though on the rope...one pull and it was running.
 
Thank you guys, ill be working this weekend but I will definitely check it as soon as possible and will get back with you. One more question If it is starter do i have to change the whole thing or there may be an easier way??
 
I would either check the voltage at the starter terminal at cranking to see if It gets sufficient voltage. Or I would jump the positive wire from the battery directly to the positve post of the start motor to see if it turns the flywheel faster.
Guessing and replacing parts will be very costly. The battery is my first doubt. Battery shows 12v, but low cranking amps won't do the job either. I use 600+ cranking amps for these motors and higher hp.
The solenoid and other connections would be my next check.
Replacing the working, but weak starter motor would be my last result.
Good luck.
 
I had some time today, I hooked the battery up but tried to start it with the rope, every time i would yank it, it would do 2-3 complete turns and makes some noise, and it does has a good spark because while my brother pulled the rope i got hit, as a result of holding spark plug improperly. I've also squirted some fuel into the carb, to see if will catch on fire, and no it did not, it did nothing, but making the noise. the noise sounds like the cylinders moving and it comes from carb, I've also tried to connecting a direct + wire to see if it will turn it fast, no it did not, only welded my wires... :)

while i was writing this message i decided to go and try it starting it again with the key. it actually almost started but for some reason starter stopped spinning the big disc. it seems like the engine tries to start, there's some kind of combustion going on, but not enough air or fuel. but i sprayed fuel into the carb.
 
Here's the basic test for all outboard motors.
1) Check the compression on each cylinder to see if compression is at a minimal of 90lbs and up. No more than 10% variation between one cylinder to another.
2) Check spark to see if it jumps 7/16'' gap and consistently
3) Remove and clean out carburators if these carbs haven't been serviced for at least 2 years. 2 stroke motors tend to have hung/stucked needle valves or floats in the carbs because the octane vaporized and left the carbs with dried oil.
4) Make sure you have a 12v batter and 675 cranking amps, all connections are secured. Clean out all rust surfaced terminals and connections.
5) Pump the primer bulb and remove the carb's drain screws to see if gas comes out of each carb.
6) Ensure your choke mechanism or electric works.
7) Crank the motor and it should starts right up. But to have it stay running you must know how to make proper adjustment with the idle screw AT TIMES only.

This is not recommended because your motor is a 2 stroke. But get a brake part cleaner or starting fluid bottle and spray it inside of the carb and try to crank the motor. If this does not help, then you need to go thru the motor like suggested above. Outboards are unpredictable and proper maintainance is required to have it start and run the way you want it to.
Once you have it run. Attach the volt meter to the battery terminal and rev the motor to see if voltage increases. If not, you rectifier is dead and it will drained your batter after a few times cranking.
Good luck.
 
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