OMC 4.3 Cobra won't turn over, bad shift interrupt switch?

mlrman

Petty Officer 3rd Class
Joined
Jun 3, 2010
Messages
82
I'm hoping some experienced OMC people can help me.

I have a 91 Sunbird with a 4.3 OMC sterndrive. last year I paid a shop to replace the shift cables. First time out, I noticed the shifter was a little stiff and I really had to throw it hard into gear otherwise it would knock like it wasn't catching fwd or rev all the way.

Also after the repair, the boat would intermittently not turn over unless the shifter/throttle lever was in the 12 oclock position. Since this doesn't give the engine any throttle, it would be difficult to start, but it would turn over. If I pressed the shift interrupt button and moved the throttle fwd, the key would not crank the engine over.

Now the problem is worse. The key will not turn the engine over at all in any position of the shifter/throttle lever. I know the battery is good. It's like the shift interrupter switch is not allowing the engine to crank over.

Can anyone point me in the right direction on what to check? I have removed the shifter assemby before, but I'm not sure what to look for in this case.

Thank you so much for any and all help!
 

mlrman

Petty Officer 3rd Class
Joined
Jun 3, 2010
Messages
82
I'm not sure my terminology is right.....by shift interrupt switch, I am talking about the button on the throttle/shifter lever that is pressed to keep the boat in neutral and move the throttle fwd.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
That button allows throttle to be applied while keeping the boat in neutral. Sounds like the neutral safety switch is not working properly anymore.

Sometimes there is some play in the switch and you can loosen up its mounting screws and move the switch.
 
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mlrman

Petty Officer 3rd Class
Joined
Jun 3, 2010
Messages
82
Thanks for the pointer. I've pulled the shifting assembly out and worked it around hoping I could find a short. I'm not sure what the neutral push button on the shift lever is called, but I my research shows the neutral safety switch is a micro switch at the shifting linkage by the engine. I depressed that, and still nothing at the key.

The engine cranks right over when I jump the starter solenoid.

I was able to find a couple wiring diagrams so I will try to track down the culprit.

If anyone has other pointers, I'd appreciate it.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,798
On some controls like the original equipment OMC controls the neutral safety switch is a separate part that can be replaced if it fails (if they are still available).
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
The neutral safety switch is in the control. The switch you pushed on at the engine is the shift switch for the ESA(Electronic Shift Assist) system.
 

Offrddrver

Petty Officer 3rd Class
Joined
Sep 19, 2009
Messages
95
No Title

Mirman,

Here is the breakdown that I'm seeing for your boat. Please confirm the setup from the pictures.
Also, if you can provide your OMC Cobra model number, that would help with further research.
It should be one of these:
The pictures:
A. Remote Control Assembly - Side mount (your gas throttle)
B. Shift Bracket (back of boat at motor)

If the build diagrams are correct, you have three switches. Please compare to your boat.
1. Neutral Start Switch (located at the bottom of your Remote Control assembly) #53 in the drawing. (E62 series cherry switch)
2. Overstroke Switch (located on the shift bracket) This is the push button (switch) that does NOT have the arm and roller. #25 in the drawing.
3. SHIFT LOCKOUT Switch (located on the shift bracket) This is the switch that has the arm and roller on it. #26 in the drawing.

From my experience (about 6 months ago) the lead/wire on the Neutral Start Switch broke off. This does not allow the motor to turn over at all. If you put a jumper (wrench) across your starting solenoid the motor will turn over.
Note that item number 1 can be ordered from Newark Electronics or Mouser Electronics online for a fraction of the cost of boat parts suppliers. (this is a standard "cherry switch") . You may be able to get all the switches there if you can get the original numbers off the three switches.
h t t p : // w w w . m o u s e r . c o m /ds/2/71/E61_Series-8833.pdf

Sorry, but I'm not in a location right now for further research on what each switch does. I suspect it will be in the SELOC OMC Maintenance manual. (my assembly is different from yours, but the full description is in the Seloc OMC maintenance manual)

In short, if your key won't start the motor, but jumping the start solenoid will, then I highly suspect it is your Neutral "safety" Start switch that is bad/broken. It was on mine.

Hope that gives you a step in the right direction.

Best regards,

Offrddrver
 

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Offrddrver

Petty Officer 3rd Class
Joined
Sep 19, 2009
Messages
95
Mirman,

Bad and maybe good news about the Neutral switch.
Bad: The cherry switch number 0E6200K0 is obsolete (that is what was on my boat that matches the diagram of the remote control assembly)
Possible good news as there is a replacement part number: DB2C-B1RC from m o u s e r only $2.62 + shipping

Please confirm your switch number with the original part (should say 1/4HP 125 VAC 10.1A 125/250 VAC E62 on it.)
Then please do your research and make sure DB2C-B1RC is a match.
There is a fairly tight fit in your remote control for this part (if yours is the same as the drawing)
I do note the terminal connection size changed from 0.093" on original to 0.110" on the new part. Therefore you will need new wire connectors.

Cherryswitches.com

Your other switches can probably also be replaced with cherry switches, but you will have to solder on wires, or add terminals to the old wires. And use liquid seal to cover the terminals for spark safety. (don't let that scare you as its the same for your coil or start solenoid or other open terminal electrical components)

OMC supplier # of assembly 986900 ? SWITCHES & CONNECTOR = $139.99 includes #'s 24, 25, 26, and 30 from the drawings. (for the shift bracket assembly)

173500 ? SWITCH, NEUTRAL START = obsolete


Hope that helps, but please do your homework on the internet (and maybe by phone) as these are recommendations based on old build books, and the part that came out of my remote control unit on a 1992 Four Winns 5.0L.

Offrddrver
 
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bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Show us a picture of your control. Not all boat manufacturers used the OMC control.
 
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