JOHNSON 50 1971 WONT START

I

imported_ROB1

Cadet
Joined
Sep 10, 2006
Messages
22
Cant get my johnson 50hp 1971 to start, when i turn the key sometimes it will start and fire up, other times i get nothing at all completely dead the flywheel doesnt even turn. i have tested across the battery terminals and have 12.5 volts so i dont think its the battery. anyone any ideas why this could be.

cheers
rob
 
Joe Reeves

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: JOHNSON 50 1971 WONT START

By the above, I assume your problem is that the engine will not crank over, but when it does the engine will start and run. Is that correct?

Remove and clean all connections pertaining to the starter circuit.... battery terminals, connections at the starter solenoid, powerhead ground, etc etc, all !

To test the starter itself, run battery cables directly to that starter.
 
I

imported_ROB1

Cadet
Joined
Sep 10, 2006
Messages
22
Re: JOHNSON 50 1971 WONT START

hi,
rob here. when i turn the key on the ignition it is completely dead and on other occasions when i turn the key it will crank and turn over and run. i take it the starter is the unit that has a cog which engages the flywheel. im not to clued up with whats what on my engine, whats the starter circuit, starter solenoid, powerhead ground. how will i know what the starter looks like to connect battery cables

rob
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: JOHNSON 50 1971 WONT START

Stop right there, Rob.

You need a Service Manual, and you need it bad.

We helpers here are a pretty good supplement to a Manual, but a bad substitute.

After you get the manual, go to the Engine FAQ section and do the starter circuit troubleshooting in "Outboard won't start". That will probably lead you to the same place Joe Reeves has taken you.
 
I

imported_ROB1

Cadet
Joined
Sep 10, 2006
Messages
22
Re: JOHNSON 50 1971 WONT START

what component is most likely to cause a problem like this, i will purchase a manual off ebay.

rob
 
D

DHPMARINE

Captain
Joined
Dec 16, 2003
Messages
3,688
Re: JOHNSON 50 1971 WONT START

That's the problem ROB. Could be any where from that key switch on back to the motor.

DHP
 
C

CharliePalmHarbor

Cadet
Joined
May 16, 2006
Messages
9
Re: JOHNSON 50 1971 WONT START

i belive it to be faulty baterty cables i had the same occurace happen and when i put on new battery cables i never had that prob again ....
 
I

imported_ROB1

Cadet
Joined
Sep 10, 2006
Messages
22
Re: JOHNSON 50 1971 WONT START

tested all the battery cables there fine. how do you test the starter motor "anyone know"?
 
D

DHPMARINE

Captain
Joined
Dec 16, 2003
Messages
3,688
Re: JOHNSON 50 1971 WONT START

Yep,put it on a bench and put juice to it.

A manual will show you how to jump wires at the ignition switch,and work back towards the motor,if you can follow a wiring diagram.

How did you test the battery cables ?

DHP
 
I

imported_ROB1

Cadet
Joined
Sep 10, 2006
Messages
22
Re: JOHNSON 50 1971 WONT START

with a multimeter. do you need to disconnect the starter motor from the engine or can you do it connected to the engine. on my starter motor i only have a positive feed to it, do you just place the positive battery cable directly onto the positive feed on the starter motor, do you need to disconnect the neutral battery lead at the engine end.
 
D

DJ

Guest
Re: JOHNSON 50 1971 WONT START

Yes,

you need a manual.

In the meantime, remove the battery ground from the engine block and clean it.
 
Joe Reeves

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: JOHNSON 50 1971 WONT START

Rob.... Manuals are sold on this site. Check here first for the one you need.

I included proper instructions in my first reply which should have guided you through the trouble shooting procedure. No offense, as per my email to you, but obviously you are not mechanically inclined and it's possible you will get hurt if you atempt to follow through by yourself. Hopefully you have a friend with mechanical expertise that can assist you with that problem.

Note that a Ohm Meter/ Multimeter is of no value to check the cables associated with the starter circuit. That meter will show proper continuity even if 99.99% of the cable is faulty, even if just one strand of the cable remains.
 
D

DJ

Guest
Re: JOHNSON 50 1971 WONT START

Follow the negative battery post lead all the way to the engine block. The connection at the engine block is the one you want to remove and clean.

Make sure the battery is disconnected before you do so.
 
I

imported_ROB1

Cadet
Joined
Sep 10, 2006
Messages
22
Re: JOHNSON 50 1971 WONT START

JOE,
what testing unit do i require. also you said "To test the starter itself, run battery cables directly to that starter" on my starter unit i only have a positive connection, do i run the positive cable directly from the battery and attach it to the starter motor, i tried this and the starter motor worked but there was one hell of a big spark from the end of the cable" scared me half to death"
p.s i have just ordered the original service and repair manual of ebay.

regards rob
 
I

imported_ROB1

Cadet
Joined
Sep 10, 2006
Messages
22
Re: JOHNSON 50 1971 WONT START

DWJ,
thanks for that im on a steep learning curve, as you have probably guessed by now. So all the info i can get is much appreciated.

ROB
 
You must log in or register to reply here.
Top