OMC ESA and Alternator wires

[chopperdog]

1988 Bayliner Ciera, 3.0L OMC cobra.
Runs great. Shifts well. The ignition interrupter isn't, well, interrupting, but it used to.
New interrupter and over shift switch. New ESA.
Here is what I think the problem is, and it shows a little ignorance on my part.

I had the alternator rebuilt awhile ago. The guy at the shop convinced me that I only needed the main wire that goes to the starter, and thereby the battery.
He suggested removing the other 2, and I agreed. He said that was standard practice.

Well, I thought I would revisit it today, and looking at the wiring diagram, it looks like those wires go through the ESA.

The alternator shop is run by a good guy, and he is reinstalling the part and wires. It will be ready tomorrow.

In any case, does this make sense?
Would disconnecting those wires, labeled EXC and 5 on the OMC wiring diagram, cause the interrupter to fail?

Thanks, and Happy Thanksgiving!

 

[woosterken]

Re: OMC ESA and Alternator wires

at the top of the motor forum is a topic titled "adults only"
#12 in that list is a service manual (down load) for OMC (thanks mr. don s)

i don't know about your question,but you mite be able to find the answer there.

woosterken

 

[chopperdog]

Re: OMC ESA and Alternator wires

Thanks.

Well, I put the alternator back in, with the reattached Excite and Start wires, and the interrupter still doesn't work.
Hmmm?

 

[woosterken]

Re: OMC ESA and Alternator wires

well then,if it didn't work with out the wires and it dont work with the wires
that kind of points the finger at the switch its self lol
i wonder if you can even still find one?

woosterken

 

[ENSIGN]

Re: OMC ESA and Alternator wires

Have you checked the switch with a ohm meter? may just be corrosion

 

[chopperdog]

Re: OMC ESA and Alternator wires

Yeah. The switch is actually new, you can still buy them. I got the new switches about 6 months ago. I tested both switches with an OHM meter, and they are good.

Interestingly, it shifts fine, even without the interrupter working.
I think I could eventually do gear damage though, so I want it to be right.

In addition, the oil pressure gauge jumps around, like it has a small short somewhere.

I think there must be something wired incorrectly somewhere, but I just can't find it.

I have been through everything.

 

[HT32BSX115]

Re: OMC ESA and Alternator wires

Howdy,

There's probably a few things you need to check besides just the switch.

Also, if you're going to try to fix it yourself, you NEED to have an OEM OMC service manual. The links above have those for Mercury and Volvo but the manuals for the Cobra are not original manuals. They are obtainable on ebay and other places. A google search will find them.


It's probably useful to know how a "clutch-dog" works I suppose,


Coming OUT of gear takes a LOT more force because the "Clutch Dogs" being slightly undercut (about 5 degrees), causes torque (when the prop is in the water) to "hold" the "dogs" together....... at idle it takes a LOT of force to get them to separate. Above idle you would probably break something (and they would not separate)

You have to place the lower shift cable in either tension or compression depending on what gear you're in when you want to put it in or take it out of gear. It should be obvious that you can produce a lot more force when the cable is in tension vs compression. [You're only going to "push" that cable so hard before it bends]


You also need to understand how the Electronic Shift Assist (ESA) system works before you can fix it. In general it "pulses" the ignition when you place "out-of-gear pressure".....either "push" or "pull", on the lower shift cable and (hence) the mechanical shift system. When you put the drive in gear, it doesn't take the same pressure or force......In fact it MUST NOT take as much pressure or you will actuate the ESA everytime you put it in gear.......

If it does actuate the ESA when going into gear, it's usually a lower shift cable that is not sliding smoothly (corrosion or bent etc) or the gimbal shift mechanism or drive itself internally is binding.

You can tell because the ESA mechanism on the engine moves far enough to operate the microswitches when you move the cockpit shift lever

Out of the water the ESA should not operate either going into or out of gear because there's little (or no) force on the clutch-dogs holding them together. testing (by shifting) out of the water won't tell you much except that the prop turns.....


When the ESA does actuate the engine will "lope" so there'll be torque "peaks & valleys" ...... In the water, since this happens when you have "out-of-gear" "pressure" on the shifter (AND lower shift CABLE), the "dogs will separate when the torque "valley" occurs.

(Mercruiser does this on the "dogs" by using an ignition "interrupt" switch. It works and some people have tried this on OMC "dogs" successfully. I don't know why OMC didn't do it other than maybe they thought pulsing electronically is "better" than a "kill" switch!)


While this might help when you go into gear it really is not required since you don't need a torque valley to get the dogs to pull themselves together when they are pushed together(by you shifting!)


Now having dumped all this info on you, it appears to me that you have an electrical problem that is preventing the ESA from working......or it's wired wrong or it's defective....(it IS an electronic device with many sold state devices epoxied on a circuit board!)

You can move the actuator manually (as you may have already done) to see if it works.

An OEM manual does have a troubleshooting procedure (with circuit diagrams) you can do with your OHM meter to troubleshoot the circuit.(assuming it's wired correctly) if the measurements are not within the correct ranges they direct you to replace parts.......


MAN, I'm glad I don't have one of these things anymore!!!


Cheers,


Rick

 

[chopperdog]

Re: OMC ESA and Alternator wires

Thanks for the info.

I have been testing the ESA out of the water. I assumed that I could detect the interruption in ignition, even without a load.
But, I see what you're saying, I think.
Basically, the inertia of the cylinders will prevent a detectable change in the idle, unless the engine is under load?
My concern, while on dry land, was that there was zero detectable change when depressing the interrupter arm switch. I expected to at least see or hear a change in RPMs.

I am waiting on a small part (teleflex cable adapter). As soon as I get that, I'll be back in the water, and can do a water test.

 

[a70eliminator]

Re: OMC ESA and Alternator wires

On muffs, at idle in neutal, you definately should detect a misfire, if you press the little micro switch button and nothing happens then it being electrically bypassed, I think you already know that, I'll take a look at the schematic I have for a 1990 it's probably the same.
Curiousity got me one day and I could destinctly hear a miss when I actuated the switch with my finger.
Ok, just looked at the schematic and it's fairly simple, both the interrupter and overstroke switch wires come together in the connector (4 go in and 2 come out) one goes to engine ground the other to the ESA module, from the ESA module you have a two wire connector, from connector one wire to coil neg. and the other to the (S) terminal of alternator through a splice that also feeds coil +
In your first post I think you meant exc and thats an S not a 5. and yes it looks like especially the S needs to be there to interrupt the coil.

 

[HT32BSX115]

Re: OMC ESA and Alternator wires

Thanks for the info.

I have been testing the ESA out of the water. I assumed that I could detect the interruption in ignition, even without a load.
But, I see what you're saying, I think.
Basically, the inertia of the cylinders will prevent a detectable change in the idle, unless the engine is under load?
My concern, while on dry land, was that there was zero detectable change when depressing the interrupter arm switch. I expected to at least see or hear a change in RPMs.

I am waiting on a small part (teleflex cable adapter). As soon as I get that, I'll be back in the water, and can do a water test.

It has nothing to with inertia.

The ESA "pulses" the ignition to cause the "loping"....... and it will be detectable if it is working (the ESA)....You will definitely hear it....in or out of the water.

If you are actuating the ESA manually (I.E. NOT using the cockpit-shifter) then you can actuate anytime you want by moving the "plate' up or down far enough to push either microswitch ....or just press either [top or bottom] micro-switch yourself

If you try to actuate it "normally"......That is, using the throttle/shift handle, It will only work in the water (with the prop installed) because that's the only time there'll be enough torque on the shift dogs to require the amount of cable tension/pressure necessary to move the actuator.

 

[chopperdog]

Re: OMC ESA and Alternator wires

Thanks for the info.
While trying to trace the wiring problem yesterday, I disconnected the ESA completely, and the engine ran fine.
I did this as a way of trying to diagnose the wiring problem.

Should taking the ESA out prevent the engine from running?
If the engine does still run, is this indicative that the problem is a short in the wires not associated with the ESA?
Does this narrow down where the problem could be?

Everythig appears to be correct. I've traced every wire associated with the system, and still can't figure it out.
I've tried 2 ESA's, and tested the switches.

Thank you.

 

[a70eliminator]

Re: OMC ESA and Alternator wires

The wire from the ESA that goes to the alt (s) terminal has a factory splice (looks like fuse link) where the it picks up the (+) coil, you could eliminate the splice being bad by checking (key on) voltage at the ESA.

 

[chopperdog]

Re: OMC ESA and Alternator wires

I've seen that splice, both on the electrical schematic and the actual splice behind the block.
It looks like shrink heated or something similar.

Looking at the diagram, does the "S" wire connect to both the (+) terminal on the coil and the wire running into the instrument cable?

I want to know what it should be like in case the splice falls apart when I open it up.

Should the engine still run with the ESA disconnected?

Thank you for all the help.

 

[carolynrose]

Re: OMC ESA and Alternator wires

All good information, here are a couple of things that turned out to fix my esa problems. Remove your overstroke cams, many times the linkage adjustment is so close that both the overstroke and interrupt will try to engage together cancelling out the misfire. The overstrokes are not even used in the upgraded esa and are useless.

Also make sure you are idling way down at about 500 - 550rpm. Anything above that my esa interruption was not even noticeable and even though operating would not help in disegagement from gear.

Even though idling out of gear you should notice the esa operation it is very subtle due to the lack of backpressure in the outdrive. There is much more "load" when the unit is underwater and therefore more noticeable.

Once you get it working take the boat for a ride and get it up to it's full operating temperature and reset the idle. A Warm engine will idle higher after "blowing it out" and the idle will need to be perfect for the gear release when shifting.

By the way my ESA works perfectly and is attached directly to battery voltage due to installation of a Pertronix Ignition system. So your alternator builder was correct unless you are still using points, then you need to have that resistor wire in place to prevent premature wearing out of the points.

 

[a70eliminator]

Re: OMC ESA and Alternator wires

I've seen that splice, both on the electrical schematic and the actual splice behind the block.
It looks like shrink heated or something similar.

Looking at the diagram, does the "S" wire connect to both the (+) terminal on the coil and the wire running into the instrument cable?

I want to know what it should be like in case the splice falls apart when I open it up.

Should the engine still run with the ESA disconnected?

Thank you for all the help.

Before you take the splice apart remove the wire from the alternator s connection and the coil + and check continuity and go from there, don't destroy the splice just yet.
Yes the coil + does run through the instrument cable but my schematic shows it as a seperate wire from the coil, ther should be two of them on the + side.

 

[chopperdog]

Re: OMC ESA and Alternator wires

Hello again.
I just went to the boat, and turned the key on.
I could not get any voltage registered on any of the pins coming out of the new ESA.

I didn't take the splice apart. I remove the black cover, and the splice looks solid. It is encased in some sort of poly resin.

I suppose that both ESA's could be shot.
I had a bad ESA, replaced it.
Then, seperately, I had an electrical issue. I had a short to ground.
I wonder if that could have blown the good ESA.

I disconnected both grey wires from the (-) terminal of the coil, and it made no difference.
Separately, I lowered the idle to 550, and still no joy when I activated the ignition interrupter.
Everything looks correct.
It's a little difficult, in that the wire colors are different than the diagrams.

I remember when I had a problem starting awhile ago, I had to bypass the ESA with a jump from the battery to the coil. This allowed me to diagnose the problem as the ESA, and that is why I got the new one.

Thanks again.

 

[carolynrose]

Re: OMC ESA and Alternator wires

There is one other thing that I tried and you may want to give this a shot. Set the interrupter like Mercruisers do. Simply take the two wires from your interrupter switch, wire one to ground and the other to the negative side of the coil and leave it like that. Completely removes the ESA module from the shift. Set the rpms at 750 - 800rpms in neutral.

When you shift the interrupter switch will breifly ground out the negative side of the coil allowing you to shift out of gear. If you like it that way, leave it.

The only problem with this is if your shift cable is stiff you may not be able to shift fast enough to not stall. But Merc does it this way.

 

[chopperdog]

Re: OMC ESA and Alternator wires

Thank you Carolynrose.

II'll try it.

I spoke with a very knowledgeable local mechanic today.
He's been working on OMC's for years.
He told me that most folks simply disable the system. It was disabled when I bought the boat, but I had it fixed for awhile.
I may ultimately just leave it inoperative, as much as I hate to have something uncompleted.
This seems okay because, as is, I can shift fine.
I was primarily worried about wear on the outdrive gears.

I appreciate your help.
I'll rewire the interrupter switch tomorrow, and let you know how it turns out.

Thanks again.

 

[chopperdog]

Re: OMC ESA and Alternator wires

I ran a wire from the (-) side of the coil today, and tested how it responded if grounded, against the quickness of my shifting system.
In short, it won't work.
As you mentioned, my shifting is too stiff.

So, I'm going to go without an interrupter for now.

 

[carolynrose]

Re: OMC ESA and Alternator wires

That will work as long as you keep the idle real low and have enough time for it to get there before you change gears.

With my last boat, an old bowrider, I would slow down to a crawl before we got near the slip and just apply steady pressure to get out of gear, worked fine, just needed to keep the rpms really down and plan the approach.

However if your shifter is stiff as you say, look into replacing the lower cable and you'll be suprised at how much easier it shifts.