OMC cobra ESA, to shift, or not to shift

[skidooseadoo83]

I posted in another thread and was advised to start a new one... Im seeing this repeated over and over again in lots of threads. I havent read anything put out specifically by OMC saying this is how it is suppose to or not suppose to work.


Ill start with my disclaimer... im not a "marine" mechanic... where can I find an OMC description of the ESA shift logic... I have seen a couple threads with people saying two completely different things and now im starting to wonder... ESA activates when shifting in and out of gear, and on this thread, only out of gear. To be honest, it makes perfectly good mechanical sense that with a dog clutch set up it would activate both ways. (a dog clutch is not a friction clutch, it simply pushes two gears, one containing engine torque continuously rotating, and the other containing the "load", stationary until engaged, together. "perfectly good mechanical sense" would be that two gears being meshed together as described will have more stress placed on them the higher the rpm they mesh at) I have an 89 capri, 2.3l cobra i/o, updated lower cable, shifts with ease, all my cable dimensions and shift measurements are within spec, no problems at all... and my ESA activates going in and out of gear. It was actually out of adjustment hard shifting when i bought it, clunked really bad going into gear, stiff shifter, no ESA stumble going into gear. After adjusting everything to spec, shifts like a dream. I know i have read literature related to the ESA stating the new 5 deg gear set was less inclined to disengage (not written by OMC, actually by Stuart) and they came up with an updated ESA that reduced RPM further to facilitate ?make disengagement easier,? this makes perfect sense... but no mention of this is made by OMC in any bulletin or manual I have read, they simply state "hard shifting,"... any thoughts? If it really isnt suppose to activate when shifting into gear i need to find whats wrong.
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[Boats-A-lots]

Re: OMC cobra ESA, to shift, or not to shift

Mine will activate going in, or coming out of gear. I can watch it when my cowl is off and my wife shifts the control. As soon as the Shifter cable holder thing on the motor starts to rock forward, or reverse, it touches that wheel on the limit switch and stumbles the engine.

 

[bruceb58]

Re: OMC cobra ESA, to shift, or not to shift

Mine will activate going in, or coming out of gear.

That is because you have other issues with your shift rod that is binding.

The ESA isn't needed going into gear. Back when I had my OMC and when it had a properly operating lower shift cable, the ESA never actuated going into gear.

To the OP, an easy way to see if its the cable causing the ESA to be activated is to take the drive off and see if it would be activated with the drive off. That way you can see if its the cable friction causing the problem.

 

[Boats-A-lots]

Re: OMC cobra ESA, to shift, or not to shift

That is because you have other issues with your shift rod that is binding.

The ESA isn't needed going into gear. Back when I had my OMC and when it had a properly operating lower shift cable, the ESA never actuated going into gear.

To the OP, an easy way to see if its the cable causing the ESA to be activated is to take the drive off and see if it would be activated with the drive off. That way you can see if its the cable friction causing the problem.

So if it's activating both going in, or coming out, that means there is another relay, or switch that is failing, or failed? Think I said that right.. in other words, that switch doesn't know itself if its going in or out. All it knows is if that button is pushed it stumbles the motor.. there has to be another switch that knows the difference and tell it to ignore going in gear. Did that make sense?

 

[HT32BSX115]

Re: OMC cobra ESA, to shift, or not to shift

That is because you have other issues with your shift rod that is binding.

The ESA isn't needed going into gear. Back when I had my OMC and when it had a properly operating lower shift cable, the ESA never actuated going into gear.

To the OP, an easy way to see if its the cable causing the ESA to be activated is to take the drive off and see if it would be activated with the drive off. That way you can see if its the cable friction causing the problem.

This is absolutely right. My previously installed OMC Cobra engine/drive in my current boat (in my signature below) was about 20 years old. While the shift actuator did move somewhat when going into gear, it never moved enough to actuate the ESA (and shouldn't)

If you want to understand how the sytem works, start by reading the following info. It's a pretty good description.
http://www.hastings.org/~stuart/cobra/


Understand, you're not just jamming a set of gears together. You're pushing sliding clutch "dogs" together that are then HELD together by the torque required to turn the propeller in a viscous liquid (water!)

The torque is enough (at idle) to prevent the dogs from coming apart easily, mainly because they're "undercut". (they're essentially impossible to pull apart with the engine running significantly above idle)

The torque MUST be interrupted or "pulsed" somehow ("stumbling the engine") to be able to pull them apart by pushing or pulling the lower shift cable to get back into neutral.

If the drive is shifted INTO gear anytime, or out of gear with no "drag" (from the water) on the prop, the force required to push them together or pull the dogs apart shouldn't move the shift actuator enough to actuate the ESA.

 

[bruceb58]

Re: OMC cobra ESA, to shift, or not to shift

So if it's activating both going in, or coming out, that means there is another relay, or switch that is failing, or failed?

No its because there is friction between the switch plate and the drive. The friction between the switch plate and the clutch dogs is what pulls the cam that hits the switch. It can be the clutch dogs being pulled apart, a bad shift cable or, in your case, your shift rod hanging up.

 

[HT32BSX115]

Re: OMC cobra ESA, to shift, or not to shift

a bad shift cable or, in your case, your shift rod hanging up.

or a combination of.......

 

[Boats-A-lots]

Re: OMC cobra ESA, to shift, or not to shift

HT32BSX115 and BruceB58.... Okay... NOW I get it. Thank you for the explanations. That will help a lot once I get the parts and get this back together and see whats it doing. I do know it acts totally different on the water then it does on the water muff and that explanation is very understandable why.