OMC Sterndrive ID

[FLOATTUBR]

1977 Hammond
235 OMC trying to understand exactly what Drive is on it.
Model# 981110
I included a pic.


The boat will die when shifted into gear, Only after running for about 45 mins or so pulling Tubers etc.
After sitting parked for (awhile to cool down I guess) then it'll drop into gear normally...???

After searching the forum and reading about the Interrupt switch etc, I don't find one anywhere like the pics I've seen.

Is this drive an "Electromechanical" or ?? I'm befuddled, Thanks in advance for your help.

 

[Boomyal]

Re: OMC Sterndrive ID

Your drive is the last year of the electric shift stringers. It is also a 'low profile' drive. There is no 'shift interrupt' or ESA system on your drive. It does have a neutral start switch which keeps you from starting it when it is in gear. If activated, you cannot even crank the starter, so I doubt that is what your problem is. I am thinking that you have something else going on that cuts the ignition, when hot. I would put a test light on the coil positive and see if it goes out when the shutdown occurs.

 

[FLOATTUBR]

Re: OMC Sterndrive ID

It'll start just fine after putting it back in Neutral and rev perfect.
It seems to us it's literally the drive killing it after pulling someone for awhile...just our guess

Thanks for your help on the ID that was killing me to find it.

 

[Boomyal]

Re: OMC Sterndrive ID

....like I said, the neutral safety switch cuts the starter. As far as I know it does not kill the ignition. It sounds like that is what is being cut when your motor shuts down. Verify it by hooking a test light to the coil positive and watching if it goes out when the motor dies.

Someone else may know more definitively.

 

[FLOATTUBR]

Re: OMC Sterndrive ID

....like I said, the neutral safety switch cuts the starter. As far as I know it does not kill the ignition. It sounds like that is what is being cut when your motor shuts down. Verify it by hooking a test light to the coil positive and watching if it goes out when the motor dies.

Someone else may know more definitively.

I'll take a light out with us next time.

We've only had it a year and we had no problem with it last year.
This year besides dying it doesn't engage at an Idle either, it engages with the throttle farther forward and a higher RPM than before, it also comes out of gear when I throttle down to near Idle.
These must be related I assume.
I did just rebuild the Holley carb and adjusted the throttle cable from where it was originally a bit. Could that be causing the comlplete problem??

Again, thanks to all of you for your help.

 

[Howard Sterndrive]

Re: OMC Sterndrive ID

there's an electrical switch inside the shifter that choreographs the shift engagement to throttle position. F or R should engage before the throttle cable starts to open the throttle plates on the carb.
If yours is revving up before engaging, you need to look at it - don't use the boat like that or you could break a clutch tang down in the drive.

I would check for voltage at the F or R wire (relative to good ground or Batt neg) as someone elese shifts. If the voltage is applied, but there's a delay in engagement, you may have a lower unit issue - such as milky gear oil and/or insulation breaking down in the clutch coils in the lower. And that might also explain the stalling if both F and R were trying to engage at the same time due to stray currents (or induced ones) in milky or otherwise conductive gear oil.

And if you don't already know, Special Type C gear oil needs to go in that lower to prevent this current(in case you have something else in there- like regular gear lube).
BRP's "Premium Blend" part # 775609 is the modern OEM Type C name
And many parts places sell a compatible Type C lube that will say so on it.

 

[FLOATTUBR]

Re: OMC Sterndrive ID

there's an electrical switch inside the shifter that choreographs the shift engagement to throttle position. F or R should engage before the throttle cable starts to open the throttle plates on the carb.
If yours is revving up before engaging, you need to look at it - don't use the boat like that or you could break a clutch tang down in the drive.

I would check for voltage at the F or R wire (relative to good ground or Batt neg) as someone elese shifts. If the voltage is applied, but there's a delay in engagement, you may have a lower unit issue - such as milky gear oil and/or insulation breaking down in the clutch coils in the lower. And that might also explain the stalling if both F and R were trying to engage at the same time due to stray currents (or induced ones) in milky or otherwise conductive gear oil.

Special Type C gear oil needs to go in that lower to prevent this as well in case you might have something else in there.

Thank you Thank you Captain Howard, that's the kind of info I was looking for. No milky oil, just changed out this spring with Type C for sure. That was one of my concerns that I'd put in C when it should have been reg oil.
I see 2 wires going into the drive so I assume those are the ones to test.
Could my adjustment of the Throttle cable housing when reinstalling the Carb cause this issue??
No wait that'd be toooo easy for me.