‘77 Johnson 70hp Starter Troubleshooting

[Jeff J]

Deleted

 

[racerone]

????---The key switch applies 12 volts to the solenoid.----The other small terminal off the solenoid goes to ground.----The solenoid connects battery to the starter.----This should be so easy to trouble shoot !

 

[HerrGruyere]

If you don't have one of these they are very handy when troubleshooting stuff by yourself. https://a.co/d/e3EhEy5
Hook one lead power and another to the crank pole on the solenoid and you can be standing at the engine checking things while sending power to crank. You ought to see on that solenoid that when you are putting power to crank that the pole from battery to starter is continuous and energized. If youve got that and you've got good grounds (and starter does nothing) then the starter is toast. You could also remove the solenoid and bench test it in a similar fashion.

If you want to test your grounds set your meter to continuity and find where the battery ground lands on your outboard and with the other lead touch each point where things should be grounded. It should ring out with no resistance. I'm all for replacing and cleaning grounds that don't look great but you can have confidence in your diagnostics by actually using a tester rather than just visual guessing. It will allow you to move forward if you know that these grounds are OK

I tested each grounding point and everything is ringing out as it should. Post from battery to ground, starter posts to ground, solenoid to ground.

 

[HerrGruyere]

????---The key switch applies 12 volts to the solenoid.----The other small terminal off the solenoid goes to ground.----The solenoid connects battery to the starter.----This should be so easy to trouble shoot !

It should! It’s why I’m so stumped.

I’ve attached some pics of everything all wired up. I used brand new battery cables and nothing. No clicks from solenoid. I am genuinely puzzled. The solenoid has the ignition wire on the “S” and the ground on the “I.” Ground wire checks out with a nice buzz from the multimeter.

Could it just be the battery at this point? I imagine the solenoid would still click with voltage applied. Maybe the original solenoid and the new solenoid are both trash?

I have the new starter but if I’m not getting solenoid clicks I’m not gonna bother with that yet.

 

[Jeff J]

My bad. I looked it up. I was thinking master solenoid. Starter solenoid gets power.

If I recall correctly, the key switch grounds the solenoid to close the circuit and provide power to the starter when moved to the start position. Could your switch or the ground to the switch be bad?

 

[racerone]

Have the battery load tested.----Often a free service.----Then take a 12" jumper wire from battery post on solenoid to small terminal ( not the ground ) on the solenoid.----Report exactly what happens.

 

[Jeff J]

What I don’t see in any wiring diagram is where any small post on a solenoid runs straight to ground.

 

[racerone]

???----It is CLEAR on the wiring diagram !----And put a wire to ground.----And it is clearly there in picture #1 post #24 as well.

 

[HerrGruyere]

Have the battery load tested.----Often a free service.----Then take a 12" jumper wire from battery post on solenoid to small terminal ( not the ground ) on the solenoid.----Report exactly what happens.

Absolutely nothing happened.

I can reinstall the new one where I cracked the hosing a little. Maybe that’ll do something.

 

[saltchuckmatt]

Absolutely nothing happened.

I can reinstall the new one where I cracked the hosing a little. Maybe that’ll do something.

Let's work backwards. Take a heavy gauge wire and touch these two connections. There will be sparks so be careful.

Post the results.

 

[racerone]

Is the battery tested to be good , yes or no ?----Is the wee ground lead on the solenoid tested and good or replaced ( see post #4 ) , yes or no ?

 

[HerrGruyere]

Let's work backwards. Take a heavy gauge wire and touch these two connections. There will be sparks so be careful.

Post the results.

Starter spun!

 

[HerrGruyere]

Is the battery tested to be good , yes or no ?----Is the wee ground lead on the solenoid tested and good or replaced ( see post #4 ) , yes or no ?

Yes, I tested that specifically with my multimeter and it beeped.

 

[saltchuckmatt]

Starter spun!

Now touch the hot lead that goes to the solenoid and then the small nut on the solenoid....not the ground obviously.

 

[HerrGruyere]

Now touch the hot lead that goes to the solenoid and then the small nut on the solenoid....not the ground obviously.

Nothing. I used a big wire this time. Tried with ignition on and off.

 

[Jeff J]

I am not familiar with solenoids that do not ground through the mount. Everything else I have worked on sends “I” to the coil, a light or it is left empty because it has bus voltage when the solenoid is engaged. The diagrams I reviewed today confirmed it for me. I don’t have the diagram for this motor but I found one wired this way in a Mercury manual. It never occurred to me “I” could be used as a ground for the solenoid.

If putting power directly to “s” on the solenoid doesn’t engage the starter, I would say you have a solenoid problem since the starter did spin when power was applied directly to it.

 

[HerrGruyere]

I am not familiar with solenoids that do not ground through the mount. Everything else I have worked on sends “I” to the coil, a light or it is left empty because it has bus voltage when the solenoid is engaged. The diagrams I reviewed today confirmed it for me. I don’t have the diagram for this motor but I found one wired this way in a Mercury manual. It never occurred to me “I” could be used as a ground for the solenoid.

If putting power directly to “s” on the solenoid doesn’t engage the starter, I would say you have a solenoid problem since the starter did spin when power was applied directly to it.

When I got the boat the ground was there. I’m hesitant to try it with the ground disconnected.

I can retry the new one.

 

[racerone]

You have checked the fuse I hope.

 

[HerrGruyere]

You have checked the fuse I hope.

That was step three haha. My push choke works so the fuse is working. Without the fuse, the choke doesn’t work.

I have another, better quality solenoid arriving tomorrow.

 

[saltchuckmatt]

That was step three haha. My push choke works so the fuse is working. Without the fuse, the choke doesn’t work.

I have another, better quality solenoid arriving tomorrow.

I am not familiar with solenoids that do not ground through the mount. Everything else I have worked on sends “I” to the coil, a light or it is left empty because it has bus voltage when the solenoid is engaged. The diagrams I reviewed today confirmed it for me. I don’t have the diagram for this motor but I found one wired this way in a Mercury manual. It never occurred to me “I” could be used as a ground for the solenoid.

If putting power directly to “s” on the solenoid doesn’t engage the starter, I would say you have a solenoid problem since the starter did spin when power was applied directly to it.

The solenoid doesn't ground through the body (notice the rubber mount). The neutral switch completes the ground allowing the engine to only start in neutral. That's why they have it.

Your comment though did help me to identify the op's problem. Scroll down to see it