1972 Johnson 50 hp

B

Bradwag

Cadet
Joined
May 8, 2013
Messages
10
Hi all.
I have a1972 Johnson 50 hp model 50esl72c. I do not have any spark to either coils. I have replaced the powerpack, stator and rectifier. I have also disconnected the black/yellow wire from the powerpack and still no spark. The electric gear case does go into neutral and motor will turn over but no spark. Was thinking maybe the timer base? Is there a way to test this? There is no power in or out of the two wires to the timer base when key is on or cranking if that matters. Any ideas out there?
Thanks, brad
 
F

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: 1972 Johnson 50 hp

By the process of elimination, it would seem that the timer base / sensor is the problem. Assuming all the parts you have put into it are good, that is the only thing left.

EDIT: To test the sensor, disconnect both leads from the power pack and connect them to a multimeter on LO ohms scale. Should read 15 ohms, plus or minus 5 ohms. Then connect multimeter between one sensor lead and ground (HI ohms scale). Should be a very high ohms reading. Zero or very low ohms indicates it is shorted to ground.

More sophisticated tests require special equipment.
 
B

Bradwag

Cadet
Joined
May 8, 2013
Messages
10
Re: 1972 Johnson 50 hp

Thanks I will test. Also, will adjusting the sensor do anything for me ? If so, how do I adjust it?
 
B

Bradwag

Cadet
Joined
May 8, 2013
Messages
10
Re: 1972 Johnson 50 hp

Tested, no continuty on the two wires to power pack, and only 3.5 ohms from sensor to ground. So does it sound like I have a short or bad sensor? Inspected wires and all look good. Thanks
 
B

Bradwag

Cadet
Joined
May 8, 2013
Messages
10
Re: 1972 Johnson 50 hp

F_R said:
It is toast
Click to expand...

Thanks I will order a new one. I have been getting everything from marine engine.com, they seem reasonable. Do you have any other recommendations?
 
You must log in or register to reply here.
Top