OMC Cobra 5.0 - Sticky Shifting

[Beachhead]

Hi, I just bought a 1987 Sea Ray 185-187 with a Chevrolet 5.0 and OMC Cobra Outdrive. Been reading on the forum here and it seems I have the issue that many have and I just wanted to check in and see what my options are.

The boat was extremely well taken care of, has 240 hours on it and looks practically brand new. Took it on the lake today and it runs well, strong, no issues other than how it shifts.

Going out of idle after starting into forward it seems fine. To get it into reverse I really have to jam the throttle back, and I can't even seem to find idle once i've put it into gear. It just goes *Clunk* from forward to reverse, skipping idle completely. I was able to find idle a few times, but it was very tricky.

When the boat is off, I can move the shifter with little effort, it's only when the motor is on that I have this problem.

I've read this could be a shift cable or the electronic shift module, but i'm not sure. I was not given any service records on the boat so i'm not sure what was done to it. I've read the hastings articles, but i'm a bit confused at this point.

Any advice would be appreciated, thanks.

 

[Lou C]

Do not keep using it this way because you will damaging the clutch dog/lower gears or bend or break something in the shift system. Do a search on my user name I have posted how to fix these to shift as well as a Volvo and better than a Merc Alpha. Too much for me to type out for the nth time....
causes:
Transom shift cable
bell crank in pivot housing
ESA must work, must lower idle from about 600 down to 450 or so.

To start what’s your idle speed? Trigger the interrupt switch with it idling in neutral does it drop the rpm?
start reading all the info is here!

 

[subcrx]

I had a cobra that haunted me for years. I would bet on your ESA module not functioning. With the engine running at idle push on the little switch with small roller on it where the shift cable is on top of the engine. If the engine does not stumble when you engage the switch you will know then that the ESA module is not working. If you have an upgraded electronic ignition this will cause the ESA to fail as well and there is a resistor mod you can do to fix that.

 

[Beachhead]

Thanks for the replies. I'm not sure what my Idle is at this time, i'd have to get it out into the lake again but i'm a little nervous to use it again at this point, I understand that I can't test this with just the muffs on?

Also I've figured out a few things since posting. This boat has both the electronic ignition, and the shift assist module. (Pictures attached)

Subcrx - Which switch are you referring? I don't see it. Picture attached showing that area if you could direct me please.

Lou - Which switch is the interrupt switch? And will search for your old posts.

Thank you.

 

[Lou C]

I have the switches marked on your pic. The way it works:
1) on the water hose there is no resistance on the shift cable so when you shift out of gear into N the ESA won't lower your idle...
2) in the water there is resistance against the prop and the shift cable jacket will flex when you try to shift to neutral, this will move the load lever (lever with the notch that the ESA interrupt switch trigger fits into) trigger the ESA and drop your idle from 600 to about 450 rpm. This drop in rpm will allow the gearcase to shift out of gear to neutral.
3) you have a Petronix conversion which eliminates breaker points. Yes its nice not to have points but the ESA system originally installed on your boat was designed to work with points. The only way it will work now is if you wire up and install the diode fix that is on the Petronix website.
4) the other switch (Overstroke switch) is supposed to keep the ESA from engaging when you are in gear, newer models did away with this and used an ESA module with a timer.

So if you run it on the water hose, hook up an accurate digital tach to the coil and get it idling at 600 or so. Trigger the little lever it should drop to 450. The engine should be in good enough tune so that it won't stall, mine never does. If you idle is higher than 1000 rpm it may not lower the idle at all. For a Cobra to shift well you need:
engine idle not more than 600
ESA working
transom shift cable works with little drag, like less than 2.5 lbs
remote cable same thing, remember its a 2 cable system both have to be properly adjusted (similar to Merc Alpha)
bell crank in pivot housing not crudded up with deposits (if the gasket between the drive and pivot housing leaks)
remote control not worn out with lost motion

Personally I do not like electronic conversions on these engines, they work just fine with points.
the second pic shows how to mark the shift cable to measure if you have equal throw on either side of neutral, this is very important and is a good check to do if you wind up adjusting the cable yourself. To do that is a lot more involved, start reading my posts.....

 

[Lou C]

PS the boat looks immaculate and for sure is worth getting it sorted. Looks like someone installed an aluminum intake and aluminum exhaust, have not seen too many of those...must be fresh water use eh? Here (salt water) it would never look that good!

 

[Beachhead]

Yeah the boat is in great shape and he did a lot of work to make it sound real nice, this shifting issue is driving me crazy though.

I have a multimeter, but I do not have a digital tachometer. I just ran the boat on muffs and tried the switch, from what I could see and hear, it did not do anything. Engine idle according to the dash gauge is approximately 500 or 600. Hard to tell really, it's about at the mid point between the 0 and the 10, it doesn't get any more accurate than that.

I'm assuming this is because the OMC shift assist "fix" was never installed. I'm not sure why he would have put the Pertronix in there and not installed the shift fix.

 

[Beachhead]

I wanted to post this video also. I shot this quick video of how it is shifting. When going into reverse, it does not "pop" like shown in Michael Romer's videos. Not sure what is causing that.

https://vimeo.com/447333524/5c01ea744e

 

[Lou C]

Are you shifting it with the engine off? If so you should have someone spin the prop or else it won’t really go into gear, dog clutch drives need to have the engine running or if engine off a helper to spin the prop. Once you get the ESA working then you can see what you have. The ESA does not activate going into gear (at least it should not) only when shifting out of gear.
You really need an accurate tach to get this sorted just like if you get into trying to set up the shift cable you need the special tools for cable adjustment and measuring cable drag. Otherwise you’re just guessing and are going to waste time. With the right tools and the fish scale to check cable drag I had it done in a day. Pulled drive set shift rod height, set up transom cable, reinstall drive and set up remote cable. Verify ESA function and you’re done.

 

[Beachhead]

Alright, i've installed a new ESA module, and now with the engine on muffs and running, it does stumble the engine when I lift the switch. It doesn't stall, but I can hear an audible difference. The old module didn't do anything when i lifted the switch.

When I shift normally via the shifter/throttle, it doesn't seem to change anything.
I'm assuming i'll need to get it into the water to accurately check this?

 

[Lou C]

Correct, because the ESA system responds to pressure on the shift cable jacket, running on the water hose there is no pressure on the prop to resist the drive trying to come out of gear. That pressure of water on the prop on the shift cable jacket moves the load lever (with the v notch) and that triggers the ESA to drop your rpms from 600 to 450. Mine will shift to neutral with one finger pressure on the control.

 

[Beachhead]

Resurrecting my old post here for the paper trail. Hoping to get some more help. I've since become much more educated on all of this.

For easier reading:
1987 GM 5.0 V8
Pertronix Electronic Ignition
Boat in great shape, purchased last year

Last year I installed a replacement Sierra ESA module, tested the switches, got correct resistance, etc. Took it out the lake a few weeks ago and it was shifting beautifully. However, after about maybe an hour of cruising around, the boat started to stumble bad, we thought the timing chain came off or something worse. It was skipping and backfiring if I gave it more than just a little bit of gas.

Got a tow back, took it home, did a bunch of trouble shooting, ordered a new CDI ESA module, and it's seeming to run fine now. Have not put it back in the water yet. I did not know at the time I could have just unplugged the ESA module and got the boat back to the dock that way.

So i've got a couple of possible issues.

1. The new Sierra ESA module I got failed after approximately an hour on the water?
2. Possible overheating coil? I did not check the coil temperature on the water. Did not know this would be a problem. I have since tested the ohms and resistance on the coil, and all the spark plug wires, they are all within spec. Coil at 1.6ohms.
3. I have not installed the "shift interrupter fix" as I think someone told me these new ESAs did not need it?

This boat has a pertronix ignition conversion, and it does have what appears to be a stock OMC black resistor wire.

My options -
- Take the boat back out and run it again with the new module, see if fails?
- See if the coil overheats? Let it cool down and try to start it up again?
- Purchase a new coil and install that before trying anything else?

I am at a loss and open to suggestions. Thank you.

 

[Lou C]

OK suggestions:
Call CDI electronics in Alabama and verify that you have the correct ESA; they used to have a tech dept that you could call and ask. You’d need the number off the side of the ESA.
Next take a good look at those microswitches. On mine I had a similar problem; engine stumbling not accelerating etc. What seemed to have happened upon investigation was the button on the switch wore to the point where it was sticking on. This was in about 2015 so the originals lasted a LONG time. So I replaced both switches and also got a new ESA from CDI. I still have the points ignition. It all works perfect to this day. If your cable is operating with low drag and all adjustments are correct, & ESA functional, you should have a smooth running and shifting Cobra.