1988 OMC Cobra 4.3L Shifting issues

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lasko1

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Main Question: Can a sticky or worn remote control shifter at the helm cause the shift assister on the engine bracket to hold the ESA arm on top of the lobes when shifting INTO gear?

I have read many posts here stating the ESA should only actuate when you are coming out of gear and that make complete sense to me.

Also the typical causes of this are related to:
  • Lower shift cable being sticky or binding
  • Bell crank needing lubed
  • Sticky Shift rod.
Background Info:
I took it to the mechanic who installed the engine and lower unit when I had the transom redone 3 yrs ago.
The mechanic has:
  • Checked adjustment measurements at engine
  • Removed the lower shift cable from bracket at the engine and manually pushed and pulled on the cable putting the lower unit into both gears. He said the cable slid very freely and does not think its the cable.
  • Visually inspected lower shift cable where it threads into bell housing on starboard side of lower unit at outdrive and it looks good (no cracks)
He concluded the remote control shifter at the helm is worn/binding and causing the issue. I agree with him in that there is some drag/binding up there and feels like it needs lubed or is worn, but I haven't read that to be a cause of the ESA being activated when shifting into gear.

Mechanic has NOT pulled the outdrive off yet. I'm still curious if the bell crank could be corroded/sticky or if the lower shift cable could be more than the 2.5 lb. drag and causing the issue and he didn't notice it without disconnecting it from the lower unit and pulling it both ways.

The boat goes into and out of gear just fine with the slight "clunk" when going into gear and no grinding of the dog clutch gears. But the shift assister keeps hanging the ESA lever up on the lobes until I physically nudge the shift assister and the ESA arm falls into the valley and the motor comes back to full rpm's.
.
The mechanic is going to pull the outdrive off next week to lube the U-joints and splined shaft and check the gimbal bearing. I'm going to request he check the bell crank and lower shift cable drag while he's got it apart.

Sorry for being so long winded, but the remote control shift at the helm is $500 and I'd like to avoid that cost if you guys don't think it'd cause the issue I'm having.

Dave
 
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HT32BSX115

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lasko1 said:
Main Question: Can a sticky or worn remote control shifter at the helm cause the shift assister on the engine bracket to hold the ESA arm on top of the lobes when shifting INTO gear?
Click to expand...

Howdy Dave,

No. If you look at how the shift plate operates, the throttle/shift quadrant is not related to how the shift assist mechanism does it's job.

It's all related to actual force required to move lower shift cable, shift linkage in the drive and force required to move the sliding shift dogs (in the drive)

You'll see if you disconnect the lower shift cable altogether. The shift plate will move and not actuate the ESA switch(s) at all.

With the drive out of the water, the force required to move the lower shift cable (when connected properly) shouldn't be enough to actuate the ESA either into OR out of gear. ONLY when in the water and when the prop is loaded with torque (turning in the water) should the force be enough to move the shift plate enough to actuate the ESA coming out of gear.

If the mechanic thinks the throttle quadrant and (quadrant shift) cable are causing it, he doesn't understand how the system works.
 
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lasko1

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That's exactly what I was thinking too...The input (remote control shifter at the helm) to the bracket on the engine should not have any influence on what happens on the backside (output) of the bracket which is the lower shift cable. Thank you for your knowledge and I'll talk that thru with the mechanic.
 
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lasko1

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Ok, I talked to the mechanic and he stated that the control box is worn and grinding bad enough (metal to metal sound) that it is continuing to hang up after its supposed to stop moving the shift cable and it is continuing to put pressure on the shift cable. At this point, I don't know exactly how the internals of the remote box work. I know there's 2 cables coming from the control box. 1 goes to the throttle and the other goes to the top of the shift bracket. Are the technical names for these two cables the "Throttle Quandrant and Quadrant Shift" cables?

Anyway, after shifting into gear, how does the control box not continue to put pressure on the shift cable when the throttle is increased? Is there some type of cam or mechanical piece in there and it only travels so far? This is where the mechanic is saying the dragging/grinding in the control box is causing continued stress on the shift cable, which transfers the stress to the shift actuator and then on to the lower shift cable. From his explanation, it sounds like something in the control box is continuing to push or pull on the shift cable when its really not supposed to be and its basically "over extending" the shift cable. Is this possible?

I need to understand how that control box only actuates the shift cable as I pull up on the red part of the shift handle and roll the shifter forward or reverse for an inch or two, and then doesn't do anything else to the shift cable while the throttle is increased.

This a 1998 OMC Cobra but I don't know any model numbers or such in order to see a schematic of the control box. Where would I find a model number??

If someone could post a schematic and general description of the control box, that would help a ton with trying to understand how the control box internals work.
 
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HT32BSX115

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All those control boxes work pretty much the same. Hard to say what you have. But if it's original, it's 28 years old.

I had an original OMC control on my 87 Four Winns, and I still replaced it with a new one similar to the Teleflex Osprey

It's the one thing you want working perfectly. If it doesn't, you could run into something or someone.

And, yes it could absolutely cause the problem if it's binding internally and applying force to the shift cable when it shouldn't.
 
Last edited:
bruceb58

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lasko1 said:
This a 1998 OMC Cobra but I don't know any model numbers or such in order to see a schematic of the control box. Where would I find a model number??
Click to expand...

Your title of your thread says 1988. So is it a 1988 or 1998? Huge difference.
 
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lasko1

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My mistake in the latter post by incorrectly stating the 1998. It is a 1988.

Last night I removed the outdrive, removed the bell crank and shift lever arm/roller, cleaned the old grease off those two parts and left them disconnected. Down there in the pivot housing, I kept the black plastic cable guide, retainer, and screw all assembled on that end of the cable.

I wanted to test the lower shift cable drag, which from reading the threads and service manual links on here, is supposed to be 2.5 lbs or less.

I climbed into the boat and disconnected the lower shift cable from the engine bracket by removing the 2 cotter pins and washer. I held the red cable sheath with one hand while pushing and pulling on the casing guide to move the cable in and out a couple times. Man, it sure felt like it took a lot of force to move that cable in and out. So I pushed the cable all the way in and hooked my fish scale through the shift pin hole and pulled until the cable came forward. It measured 8-10 lbs. I then went out of the boat to the pivot housing end and used the scale to pull the cable back that way. Again 8-10 lbs. And, this is without the bell crank or shift arm/roller attached. 2.5lbs of drag must feel like the cable is gliding thru butter compared to what mine currently feels like.
As long as I?ve done the above mentioned procedure correctly, the lower shift cable appears to be the major culprit of my issue just as many of you experienced folks have suggested.

Question: How far of a stroke should I have been making when pulling the cable in either direction? I may have to redo my drag test if the full stroke wasn't necessary and only need to go a short distance from the neutral position.

Question: Use OEM cable or Aftermarket? Aftermarket is definitely cheaper, but are they the same quality and spec?s? I?ve heard rumor that some of the Sierra cables in the past were not the same length as the OEM and made adjusting difficult. Any thoughts or recent experiences using Aftermarket cable?

Now, on to the remote control box dragging issue. With the lower shift cable still detached from the shift bracket on the engine, I shifted into forward with the remote and it did still make the grinding (metal to metal) noise but it was considerably less than it did when the lower shift cable was attached. I also shifted into reverse and that seemed to go pretty smoothly with very little, if no, drag at all.

Question: Can this remote control box be lubricated/serviced to extend its useful life by reducing the slight drag while going into the FWD position?

I really don?t have anything to compare the amount of drag/grind of the remote box to, since this is my first and only boat that I?ve shifted using a remote box. My plan is to take it over to a reputable boat shop and see if they will actuate the control box and tell me if the shifter is still usable, serviceable to lube, or if it is too far gone and needs replaced.
 
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HT32BSX115

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lasko1 said:
My mistake in the latter post by incorrectly stating the 1998. It is a 1988.


Now, on to the remote control box dragging issue. With the lower shift cable still detached from the shift bracket on the engine, I shifted into forward with the remote and it did still make the grinding (metal to metal) noise but it was considerably less than it did when the lower shift cable was attached. I also shifted into reverse and that seemed to go pretty smoothly with very little, if no, drag at all.

Question: Can this remote control box be lubricated/serviced to extend its useful life by reducing the slight drag while going into the FWD position?

I really don’t have anything to compare the amount of drag/grind of the remote box to, since this is my first and only boat that I’ve shifted using a remote box. My plan is to take it over to a reputable boat shop and see if they will actuate the control box and tell me if the shifter is still usable, serviceable to lube, or if it is too far gone and needs replaced.
Click to expand...

You can test the remote operation by simply disconnecting both the shift cable and throttle cable at the engine and observe both cable ends.

When you move the shifter from neutral to forward or reverse, the throttle cable shouldn't move at all.

Then when you move the shifter further to open the throttle, the shift cable should not move.

If they BOTH move, it's probably dragging/binding in the quadrant. You can take the quadrant apart and lubricate it but if it's worn out, you should replace it. It's doubtful you will find parts to repair a 30 odd year old shifter. New shifters aren't all that expensive. drives cost a LOT more.

Most of those shifters are made to work on many stern drives and outboard motors. Inside the shifter, there's different settings (hole-positions to mount the end of the cable) that allow different shift-travel for the shift cable when going into gear.

Also, when in the water, do not SLOWLY place the drive in gear with the engine running. It will rapidly wear out the shift dogs.
 
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lasko1

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Tonight I'll try your suggestion of disconnecting the shift and throttle cables:

"When you move the shifter from neutral to forward or reverse, the throttle cable shouldn't move at all. Then when you move the shifter further to open the throttle, the shift cable should not move."

If I don't see movement as mentioned in quotes above, I take it that means the control box is okay and could just use some lube.

Will report back tomorrow morning. Thank you guys for your inputs.
 
bruceb58

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The problem with using a controller that is worn with an OMC Cobra, is as the control wears, its full range of motion on the cable throw gets less and less. This is death for Cobra dog gears.
 
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lasko1

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Ok, last night I disconnected the quadrant shift cable and throttle cable at the engine. I shifted the control box into forward and reverse and the shift cable moved first without the throttle cable moving. Then as I opened the throttle more in each direction, the shift cable didn't move. It appears to be actuating properly at this time.

Bruce, I am taking your advice and I am sneaking out of work here at noon and taking the boat to the repair shop to get their opinion on the control box's condition. I talked to him on the phone and he said they are serviceable and able to lube if not too far worn.

I will search the web for control box removal and lubrication instructions to see if I can tackle that myself. If anyone knows a link to the instructions, please post. I just want to know what to expect when taking it apart so I don't get surprised by a spring or other parts flying apart and me losing them in my garage when I disassemble it to lube it.
 
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lasko1

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I forgot to mention that the dog clutch engages both FWD and REV with no grinding as I do a smooth shift into either gear in the water with the boat running. My main problem at this time is that shift actuator is holding the ESA switch on top of the lobes when going into either FWD or REV and the engine continues to run at the reduced rpm's until I physically go back and nudge the shift actuator and then the ESA drops back into the valley and the engine rpm's return to normal and it runs great.

Most recently, I noticed I can replicate this issue with the boat turned off and out of the water. With the engine cover removed and me at the helm, I can look back at the engine and as soon as I start to shift slowly into gear, I can see the shift actuator move and begin to move the ESA arm up onto the lobe.

Since I did the drag test on the lower shift cable with it disconnected from the engine bracket end and the bell crank and shift arm/roller removed, I measured 8-10 lbs. of drag in both directions.

Plan forward is to replace the lower shift cable and investigate how worn the control box is.
 
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HT32BSX115

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lasko1 said:
My main problem at this time is that shift actuator is holding the ESA switch on top of the lobes when going into either FWD or REV and the engine continues to run at the reduced rpm's until I physically go back and nudge the shift actuator and then the ESA drops back into the valley and the engine rpm's return to normal and it runs great.

Most recently, I noticed I can replicate this issue with the boat turned off and out of the water.
Click to expand...

2 things..... <assuming the cables are adjusted correctly>

1. If the ESA activates when going INTO gear, there is enough binding (in the lower shift cable or drive/linkage) to cause it
2. The ESA should never actuate going into gear (or out of gear when out of water) If it does, see #1.

Look at the Shift Actuator you'll notice that there is a "lever action" going on there: If there is enough resistance to movement of the lower shift cable (from moving the cable itself (and/or the drive linkage and sliding shift dogs) The Shift actuator will overcome it's own springs and move far enough to actuate the ESA micro switches.

If there isn't enough resistance .......I.E. going into gear normally................ or out of gear [when out of the water]
the actuator shouldn't move far enough to actuate the switches (although it's normal for it to move around a little......)

When the drive is in the water, the sliding shift dogs are harder to pull apart because of a 3-5 degree undercut which (due to torque),

When you actuate the ESA, the ignition "pulsing" produces torque pulses sufficient to pull the clutch dogs apart on a torque "low" .......
. (The ESA is not required to push those shift dogs together......If it does actuate, the engine can die when the torque (low) pulses are coupled with the added torque of turning the propeller)


If you have even a little resistance, it can be enough to make that shift actuator move every time you move the shifter. (but that resistance will always be from the lower shift cable (if it's rusty/frayed/etc) or binding linkage inside the drive or transom mount.
 
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lasko1

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Update....I went to the boat shop and had them "verify" with their experience that the lower shift cable had too much tension on it while it was disconnect at both ends. I picked up the OEM cable for $200

Now, what's the best way to remove the old cable from the pivot housing? The guys at the shop said they don't remove the pivot housing when replacing the lower shift cable.

I'm having trouble removing the fitting out of the pivot housing. I had a buddy cut a slot the width of a pencil down the entire length of a 3/4" socket so it will fit over the cable. He also ground flat edges onto the outer part of the socket so I could get a wrench onto it and turn the socket. I am able to loosen the fitting in the pivot housing, but every time I remove my wrench from the socket to get another bite, the fitting turns back into the housing due to the entire cable not spinning. I could just cut the cable down there at the pivot housing and remove the fitting, but how would I install the new fitting without encountering the same cable binding?

Should I remove the pivot housing? If so, I will have to remove both worm-gear clamps from the driveshaft bellow and the exhaust bellow. I am comfortable doing that, but I need to know the difficulty of getting those ends of the bellows back on. Also, is the driveshaft bellows just clamped onto the part coming out of the transom, or is there any adhesive/sealant applied before clamping that bellows back on?
 
MRS

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You have to take the pivot housing off then you can remove the transom shift cable off.
 
Thajeffski

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nevermind, got it. just have to hope I put it all back together the right way.
 
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lasko1

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got my shift cable and pivot housing back together. According to the boat shop, DO NOT put anti-sieze on the pivot housing bolts that you remove with the 1/2" allen wrench. He said if anything, put Loc-tite on them as they tend to want to loosen up. My starboard side bolt was loose when I removed it, so I believe him. Torque them to 105-120 ft/lbs per manual. Thank you bruce for the link....two thumbs up to you :)
 
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