1968 40HP Evinrude Electric Start problem

[andreipou]

Hello,

I have 1968 40HP Big Twin Evinrude that I rebuilt while ago.
Ran fine for two seasons.
Started fine this morning , then on the lake electric start died.
No click at all.
Rope start works fine.
Motor runs fine after rope start.
Tried to troubleshoot at home.
Cleaned all contacts, good battery fully charged.
No click.
Applied 12 Volts to solenoid's small contacts, clicks fine, starter runs fine, motor starts.
Put volt meter on these small solenoid's contacts one after another and turn key to Start - 12V goes to those contacts fine, does it mean switch is good?


Can not figure what else to check.
Help please!!!

Thanks.

 

[jimmbo]

Wiring dia for the 40hp electric shift. Just ignore the electric shift stuff, and maybe the generator.

http://maxrules.com/graphics/omc/wiring/67_68_40HP.jpg

If the throttle too far advanced the safety switch will keep the solenoid from working. But you said you put voltage thru it and the starter cranked. I will assume you hooked the solenoids small terminals, one to plus, one to minus, on the battery? If so that would take the safety switch out of the circuit. If retarding the throttle doesn't allow power to the solenoid, try grounding the terminal of the solenoid that goes to the safety switch, then see if it cranks?

 

[andreipou]

". I will assume you hooked the solenoids small terminals, one to plus, one to minus, on the battery"

Correct.

Will try your suggestion tomorrow morning.
Tnx.

 

[andreipou]

"grounding the terminal of the solenoid that goes to the safety switch" did the trick!!!


Now I have to figure what happened to this switch.

What should I do ?

 

[oldboat1]

What motor do you have (model number)?

 

[jimmbo]

What motor do you have (model number)?And where is the neutral safety switch located

It is located by the armature plate. Rotation of the armature plate opens/closes switch

 

[oldboat1]

Thanks, jimmbo. Too quick with the edit button -- was second guessing (not sure whether focus is on the vacuum cutout switch or neutral safety switch.)

 

[jimmbo]

Thanks, jimmbo. Too quick with the edit button -- was second guessing (not sure whether focus is on the vacuum cutout switch or neutral safety switch.)

They are wired together, A couple of weeks ago F_R gave a real good explanation of how the two worked as a combo.

I remember busting the Vacuum cut out my dads 40. Good thing I was caught in the act of repair, my clandestine repair created a shorted switch. The old man would have been pulling his hair out trying to troubleshoot that on the water.

 

[andreipou]

Model 40853D.

I tested safety switch.
It is installed according to manual diagram and is open (no connectivity) until you open throttle all the way, then it closes.

I took off and disassembled vacuum cut off switch.
Cleaned it , checked by sucking air out and watching ohm meter showing connectivity when suction is applied.

Disconnected and removed wire harness that connects solenoid , cut-off switch etc.
Checked every wire for connectivity.
All looks fine.

Need help.
What else?


"A couple of weeks ago F_R gave a real good explanation of how the two worked as a combo" - Can not find it...

 

[andreipou]

I am trying to understand what safety switch does.

When I start motor and throttle is on low speed\idle the button on the switch is pressed and it provides grounding for the solenoid.
When I turn throttle to high speed , button goes to the slope on the armature plate and gets released breaking the connectivity to the ground.
It serves dual purpose:
1. Cut-off vacuum switch can not cut-off spark on cylinder anymore on high speed
2. Solenoid can not start starter.

Am I right?

In this case it feels that for some reason switch breaks connectivity when I try to start, what is wrong.

Am I thinking in correct direction?

If yes , I would have to get fly wheel off and check the switch adjustment.
Just do not want to do it if I am wrong.


Please advise.

Thanks.

 

[oldboat1]

Model 40853D.

I tested safety switch.
It is installed according to manual diagram and is open (no connectivity) until you open throttle all the way, then it closes.


"A couple of weeks ago F_R gave a real good explanation of how the two worked as a combo" - Can not find it...

This is probably the reference thread you are looking for: http://forums.iboats.com/forum/engi...0445509-1972-johnson-125-no-start-this-season

Note that the safety switch has to be closed and grounded for the starter to work -- as you apparently did when you attached a ground jumper at the small solenoid terminal.

(You may also have a neutral safety switch in the control box.)

 

[andreipou]

Sound like my case .
I will get to is on Thursday.

Too bad I need to get wheel off just to get to this switch...

 

[oldboat1]

Don't know if you have done it before, but need a harmonic balancer puller for the flywheel. Check the key. Earlier 40s took about 105 ft lbs torque for the flywheel nut, so think yours probably requires the same (clean the tapers first -- must be completely free of grease).

 

[andreipou]

I was able to do it without removing wheel.
Took some fine adjustment.
Not sure how it got "unadjusted" , it was very tight...
But , problem solved.

Thanks everyone!