‘77 Johnson 70hp Starter Troubleshooting

HerrGruyere

Cadet
Joined
Sep 1, 2025
Messages
6
Hi!

I have a ‘77 Johnson 70hp (70el77s). She’s sat for 20 years. Last year with a crap battery, I got a couple of weak turns when engaging the starter. This weekend, I got a new battery and nothing happened when turning the key. Some things to note:

Cleaned all connectors to super shiny (terminals from battery to solenoid, battery to ground, solenoid to starter, etc.).

Choke engages when pushing key.

I get 12V at the solenoid from the battery.

I get 0V when key is turned to start. I may have measured wrong, though. I put the pos lead on terminal to battery and negative lead on solenoid to starter.

No clicks or hums from solenoid.

Taking the lead from battery and touching to starter lug does nothing but spark.

Cracked open the remote control and didn’t find a neutral safety switch. No wiring is on the motor that I can see near the gear levers.

Sprayed connections with WD-40.

My guess here is bad starter and solenoid and possibly a bad ignition switch. Just checking with the experts to make sure I’m on the right track. Please let me know if I’m missing something. I’ve scoured the Internet but getting mixed results.

Thank you!!
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,926
Replace the wee ground wire from solenoid to the block.----Find the neutral switch in the control box.----Or maybe some one took it out.----Find the wires and tell if they are connected.
 

HerrGruyere

Cadet
Joined
Sep 1, 2025
Messages
6
Replace the wee ground wire from solenoid to the block.----Find the neutral switch in the control box.----Or maybe some one took it out.----Find the wires and tell if they are connected.
I think someone removed it or it never existed. I’ve tried jiggling the lever real good while holding the key and nothing happened. There are no things plugged in or resting near the cams on the inside.

Ground wire from solenoid to block is a good idea. I have some wire laying around I could use.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,926
When it left the Johnson factory there was a neutral switch in the control box.----I can not see or touch your motor.----Here it would be easy to solve this puzzle !
 

HerrGruyere

Cadet
Joined
Sep 1, 2025
Messages
6
When it left the Johnson factory there was a neutral switch in the control box.----I can not see or touch your motor.----Here it would be easy to solve this puzzle !
I bet I could see once I get it off the side of the boat. Gotta find the bolts on the inside.

I have a starter and solenoid (both returnable) on the way.
 

HerrGruyere

Cadet
Joined
Sep 1, 2025
Messages
6
Wrong starter arrived :/

I cleaned up all the grounds. I ran a small jump from the terminal from battery to each one of the small nuts (“I” and “S”). Nothing happened. While my daughter held the key on start, I checked with a multimeter (correctly this time!) from battery terminal to “I” and “S”. I think “S” had nothing and “I” had the voltage (I was in a hurry). Battery still measuring healthy with key held down. 12.6V anywhere voltage measured. I also spun the starter with a wrench and it turns nice and free. Checked the cables for crunchiness, and they are all pliable. Jiggled the everliving mess out of the shifter while holding start. Turned the motor a whole bunch, too. Nada.

My new solenoid arrives tomorrow. We’ll see if that works. There is a black cable running under the flywheel. It’s connected to the throttle linkage. I can’t quite access it. Looks pretty clean, but could that be my bad ground?

Is it also possible to just bypass the neutral switch in the remote control by bridging the two wires from the switch?

One last thing: could I move the neg ground off the post on the manifold to one of the starter mounting bolts? I was getting some flicker on the multimeter when checking stuff. This might also explain why nothing happens when I jump the starter.
 
Last edited:

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,926
Find the wiring diagram online !-----The " lets see what happens if I hook up this wire "----Can create smoke and cost you big money.
 

Jeff J

Petty Officer 2nd Class
Joined
Jun 23, 2021
Messages
189
“Cleaned all connectors to super shiny (terminals from battery to solenoid, battery to ground, solenoid to starter, etc.).”

What about the nuts, bolts, washers and engine surfaces where these connectors connect?
 

HerrGruyere

Cadet
Joined
Sep 1, 2025
Messages
6
“Cleaned all connectors to super shiny (terminals from battery to solenoid, battery to ground, solenoid to starter, etc.).”

What about the nuts, bolts, washers and engine surfaces where these connectors connect?
You know it! Cleaned those nice and shiny, too.
 

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,899
Wrong starter arrived :/

I cleaned up all the grounds. I ran a small jump from the terminal from battery to each one of the small nuts (“I” and “S”). Nothing happened. While my daughter held the key on start, I checked with a multimeter (correctly this time!) from battery terminal to “I” and “S”. I think “S” had nothing and “I” had the voltage (I was in a hurry). Battery still measuring healthy with key held down. 12.6V anywhere voltage measured. I also spun the starter with a wrench and it turns nice and free. Checked the cables for crunchiness, and they are all pliable. Jiggled the everliving mess out of the shifter while holding start. Turned the motor a whole bunch, too. Nada.

My new solenoid arrives tomorrow. We’ll see if that works. There is a black cable running under the flywheel. It’s connected to the throttle linkage. I can’t quite access it. Looks pretty clean, but could that be my bad ground?

Is it also possible to just bypass the neutral switch in the remote control by bridging the two wires from the switch?

One last thing: could I move the neg ground off the post on the manifold to one of the starter mounting bolts? I was getting some flicker on the multimeter when checking stuff. This might also explain why nothing happens when I jump the starter.
If your doing a direct feed from the battery to the starter and it doesn't do anything your starter is no good.
 
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