OMC ESA roller switch cam question

[MR2010]

I have a question on the OMC shift interrupter switch (the one with the roller) and the metal "W" cam that presses it. When I shift from F to N or R to N the metal "W" cam barely moves and does NOT make contact with the ESA roller switch. I do not understand why this cam does not engage as the TBSC cable does move and shift both F and R. The cam mostly sits in the neutral position not touching the roller switch. Any info on the cam actuation would is appreciated. I have already read the OMC technical document from hastings.org website.

 

[cr2k]

Re: OMC ESA roller switch cam question

The switch is there to cut the engine power should there be pressure on the cable. It will not do anything out of the water.

 

[Black as]

Re: OMC ESA roller switch cam question

You have to pull apart the assembly and lubricate the pivot points and also check the nylon bushes that they are not worn out. Also check that the unit "W" section is well bolted down and also doesn't have to much sideways movement.

I had the same problem that you have, pulled it all apart and did the above and works well now. I also had to bend the arm on the ESA module to make contact with the "W" actuator to make it work. Also had to shim the unit to eliminate sideways movement. Its a pig of a set up but take your time with it because once you get it right it will shift gears very smoothly.

Good luck

 

[bruceb58]

Re: OMC ESA roller switch cam question

It is only needed going out of gear and should only occur when you are in the water with a load on it like CR2K said.

 

[Black as]

Re: OMC ESA roller switch cam question

I have a question on the OMC shift interrupter switch (the one with the roller) and the metal "W" cam that presses it. When I shift from F to N or R to N the metal "W" cam barely moves and does NOT make contact with the ESA roller switch. I do not understand why this cam does not engage as the TBSC cable does move and shift both F and R. The cam mostly sits in the neutral position not touching the roller switch. Any info on the cam actuation would is appreciated. I have already read the OMC technical document from hastings.org website.

Put your boat in the water and put it into gear, then put it back into neutral this is when the ESA module needs to work again in reverse then back into neutral, If you cant get it back into neutral either way easily means your ESA module set up inst working correctly.

 

[MR2010]

Re: OMC ESA roller switch cam question

cr2k: The ESA cam will not actuate out of water? I will have to see in water next time. How would the cable get that input? I ran the engine out of water (with garden hose) and shifted both ways and the cam does not move. I have observed sometimes movement but past the shift point and on the way to throttle. I have the correct spring on the ESA cam and the "red" (recalled OMC cable) TBSC cable. I guess I will have to check pivot points and trunnion per 'black as' comment, although I don't see much play there.

Not sure where in the shift throw the ESA cam gets moved. Seems reasonable it would move early in the cable throw before the shifting happens. I just don't see how TBSC cable does that as the complete cable movment is one action involving both the ESA cam and shift cable.

And does not the ESA work for both going into or out of F or R? I seems like it should to assist shifting. I manually pressed the lever and the RPMs do drop indicating ESA working OK, just the cam is not appear to be working.

I suspect I may need a new TBSC cable as mine is over 20 years old with about 225 engine clock hours. I am having problems on my last time out (2 days ago) with shifting where it will not always come out of F and will not even go into R. The cables from helm to engine are fine and cable throw is per spec with no play from helm to engine. When I disconnect the TBSC cable and move by hand both R & F almost always work, especially if I move the cable quickly. I did see once in my testing that manually moving the TBSC slow to R it did not even try to shift. I may have damaged the bellcrank when I lubed the u-joints and gimbal a month ago. although the very next time out on the boat every thing was perfect. I only noticed an increasing problem on my second time out this year. I did add about 3 ounces of gear oil to the outdrive on my second time out (I did refill the outdrive from the bottom plug to avoid air bubbles) not that that seems to be significant and may just be coicindence. Just going through "what changed since last know working condition"

I have seen a lot of posts on replacing the TBSC and it sounds like a lot of work. The OMC manuals (as I have read from www.hastings.org website) say to replace the TBSC if the outer jacket is "ribbed". I am not sure if mine is or not or what "ribbed" would even look like.


My boat is 1988 4.3L OMC Cobra.

 

[MR2010]

Re: OMC ESA roller switch cam question

Well I now understand the ESA cam and how it gets activated. The pressure from the prop spinning in the water makes resistance and makes the cable coming from the outdrive pull harder causing the entire TBSC to pull on the ESA cam making it move to engage the roller switch. Interesting concept to make the ESA engage only when needed due to resistance.

I still may have a bad TBSC and need to get that replaced. I am going to test a bit more before going through all the trouble and expense of replacing the cable.

 

[bruceb58]

Re: OMC ESA roller switch cam question

(I did refill the outdrive from the bottom plug to avoid air bubbles).

That is actually the wrong way to fill a Cobra. It needs to be filled from the middle hole.

 

[Black as]

Re: OMC ESA roller switch cam question

Also ensure your cables are fixed firm from the hand throttle all the way to your motor.

 

[Dzrtcj7]

Re: OMC ESA roller switch cam question

I'm very interested in hearing what you figure out on this. My '89 OMC Cobra is doing the exact same thing. The "W" bracket doesn't appear to be moving enough to engage the ESA switch. I also noticed that it appears the "in gear" micro switch doesn't appear to be engaging the two posts to prevent the ESA from working while completely in forward or reverse.

I have the Red shift cable, and only 80hrs on the outdrive since an OMC Reman. Mine just suddenly stopped working while out on the water one day. I have yet to go through the Hastings adjustment procedures. Hopefully I'll get to do that next week and it will solve my problems. The friction/ force system to engage that ESA micro switch seems like it would be very touchy ....

 

[bruceb58]

Re: OMC ESA roller switch cam question

The "W" bracket doesn't appear to be moving enough to engage the ESA switch.

Is this on land running on muffs or in the water?

You should start your own post on this so your answers don't get blended in with the OPs

 

[MR2010]

Re: OMC ESA roller switch cam question

Thanks BruceB on the filling from middle hole. I had read that somewhere else too. When I filled the outdrive I followed instructions from either a shop or something I read from online going from the bottom. I used a hand pump to fill from bottom and got all 64oz in. At first I did not understand why you needed to go from the bottom. But the idea is to avoid air bubbles that you would get filling from the top. Next time I will have to try the middle hole.

I was running on land with the muffs.

My cables from helm to engine are tight. I pulled apart my shift box and everything is tight there too.

I was out on the boat again today and found if my RPMs are VERY low, ie, 450-550 I can shift perfectly F N R. This is to low though as my engine quits 1/4 the time.

My ESA IS working, I tested it again today. When manually moving the roller switch my engine RPMs drop as it should. I tested the switch with RPMs at 650-750. I can't tell if the RPMs slow down when I adjust the idle screw to 450 RPMs and then press the switch. I do not know if that is normal to not notice it at such a low RPM but I can't detect it. I read on another forum (can't remember which one) that bad points may cause the ESA to not act properly. Anyone heard that?

"Dzrtcj7", the ESA "W" cam will engage when there is back pressure in the outdrive due to the prop spinning in water, which you wont get on land. From what I can tell the entire cable jacket moves pushing the cam to engage the ESA roller switch.

At this point I am not clear as to why I am having difficulty shifting. Is it points/ignition in combo with the ESA? Is it a worn TBSC cable? I have not removed my outdrive to inspect for "ribbing" on the TBSC jacket. I do not even know what "ribbing" of this cable would even look like. If anyone has a picture, or describe it, that would be great.

 

[bruceb58]

Re: OMC ESA roller switch cam question

When you have a worn cable, you would actually get the ESA to operate while on the muffs. Even at 450 RPM, I would think you would get a stumble but can't attest to that fact. I don't have my Cobra anymore.

If for some reason the overstroke switch is activated, the interrupt switch will not activate the ESA.

As far as the cable goes, you can look at it to see if it is ribbed easily. Its just the cable housing. If its smooth its not ribbed.

You should aslo check the part number of the ESA. Not sure how many cylinder engine you have but if someone happened to replace it at one time with one for a different cylinder engine, it won't work properly.

At one point in time, OMC did have a recall on the springs that allow the ESA to work easier. What year is your engine? Also, there is an updated ESA that came out in the early 90s that uses a timer instead of the overstroke switch. I am not sure what else was modified for the redesigned ESA module.

 

[MR2010]

Re: OMC ESA roller switch cam question

Well that sounds good then as I have only seen the ESA get engaged once or twice after 20 shifts FNR while on the muffs. Should it NEVER get engaged on the muffs? And it seems to only engage past shift stroke and on the way to throttle stroke. I definitely hear the stumble at 600+RPM but can't really tell at such low RPM of 450. Should the ESA always get engaged? Or only when under pressure as in 650+RPM or going into reverse?

I confirmed the overstroke cam does cut the ESA but only gets hit just between the shift stroke and throttle stroke. The overstroke switch also seems to prevent starting the engine if trying to restart out of neutral, which only makes sense.

So is "ribbing" of the TBSC jacket the main method of determining worn TBSC? Is worn TBSC happen in number of hours of use or years old? My TBSC is red and was replaced with the OMC recall back in 1989 or thereabouts. I have 225 engine hours since then.

My ESA is correct for my 1988 6 cyl 4.3L

My ESA spring is the revised one per the pictures I have seen on http://www.hastings.org/~stuart/cobra/kw-shift.html web site.

I don't remember my ESA being replaced on my 1988 4.3L. Using the timed method that makes better sense as the overstoke cam could quickly get hit before the benefit of the ESA is realized.

The shifting is unpredictable and seems to be based on extremely low RPM or non pressure on prop. IE, while coasting forward in F at 1000RPM then quickly going to N I can get it out of F. Other times when returning to N from F it will still be going forward. If I kill the engine, and still slightly moving forward, it will go to N. Very strange.

 

[bruceb58]

Re: OMC ESA roller switch cam question

So is "ribbing" of the TBSC jacket the main method of determining worn TBSC? Is worn TBSC happen in number of hours of use or years old? My TBSC is red and was replaced with the OMC recall back in 1989 or thereabouts. I have 225 engine hours since then.

The shifting is unpredictable and seems to be based on extremely low RPM or non pressure on prop. IE, while coasting forward in F at 1000RPM then quickly going to N I can get it out of F. Other times when returning to N from F it will still be going forward. If I kill the engine, and still slightly moving forward, it will go to N. Very strange.

The ribbed housing is what the original shift cables were...you don't have that since it was repalced for the recall.

The fact that you aren't going out of gear when you shift to neutral is an indication that your shift cable is out of adjustment. That could be just a case of cable stretch over the years but can also be caused by a failing cable. Take a look at the cable housing where it enters the drive. You can do that by tilting the drive up and look underneath on the starboard side. If the housing does not look perfect, it means the cable is failing. That is where they usually fail. Also, it is always a good idea to store your drive in the down position. One reason is that the shift cable has less of a bend in it when the drive is always down.

When you shifted from forward to neutral and the boat didn't go out of gear but then went out of gear when you turned the engine off is expected. The reason is that the dog clutch has a bevel and will try to stay mated while under pressure from the engine turning the prop. Once you turnoff the engine, the pressure is released and the pressure of your shift cable trying to take it out of gear pulls it out the rest of the way.

I would bet its the lower shift cable. I was actually never able to get close to the life you have on yours before I replaced mine. I replaced mine many times.

 

[MR2010]

Re: OMC ESA roller switch cam question

Bruceb58: Thank you very much! You called it correct and are exactly right. I just now looked at the outdrive and it is just as you stated. The red TBSC jacket is completely pulled away from the outdrive and the inner cable is visible by about 1 1/2 inches.

And thank you for the tip on leaving the outdrive in the "down" position. I have always stored out of water and left it in the UP position. It completely makes sense now that in the up position you are stretching EVERYTHING out, including bellows etc.

BTW: What is the best online boat place to purchase replacement parts? I am looking wholesalemarine.com and the TBSC is $79.46.

Also, can you recommend what other pieces besides the cable, such as gaskets, bellcrank, etc etc? that may need to be replaced with the cable.

 

[bruceb58]

Re: OMC ESA roller switch cam question

http://www.fasteddiesmarineparts.com/
will have the best prices around.

Of course you will be pulling the drive and need a gasket set for that. Best if you have the factory manual because adjusting the cable is tricky. If there is a dealer nearby that has the plate that sets the bellcrank at the outdrive at 90 degrees for you to borrow would be great. Mine rents it for $5. When you pull the drive inspect/lube the gimbal bearing and u-joints and check the alignment of the drive with an alignment bar.

 

[MR2010]

Re: OMC ESA roller switch cam question

The documentation from http://www.hastings.org/~stuart/cobra/kw-shift.html seems to be very comprehensive with photos and scans of portions of the old OMC manuals. But, I do not see anywhere additional gaskets, seals etc other than the obvious drive gasket set. Is there a gasket around the TBSC where it enters the drive and connects to the bellcrank area?

Before your describing how to view the TBSC cable with the drive still attached I did not even know you could. I thought somehow it was all contained in a bellows or something. I don't have the drive off yet but with the cable outside I guess it just attaches to the drive with a gasket or something between the drive and bellcrank then goes through the transom inside a large rubber hose up to the engine. seems pretty simple.

I must admit I am a bit nervous trying to adjust the cable but it all seems to come down to having 7 5/8 (+- 1/32) on the engine end of the TBSC from the center of the shift pin hole to and cable crimp.

Since the cables, shift box, engine shift assembly bracket all are good, moving freely and in range I don't expect to have to adjust the overstroke cams or anything else. Since you have done yours a few times (back when you had the cobra) does this sound about right?

I have done more complicated projects so I am game. But first time is always a bit stressful. When I first removed the outdrive a few years ago it was intimidating, but after doing it I said "this is easy" (well except for getting the u-joint shaft back through the rubber bellows which too awhile).

Thanks again Bruce for the help!

 

[bruceb58]

Re: OMC ESA roller switch cam question

I don't have the drive off yet but with the cable outside I guess it just attaches to the drive with a gasket or something between the drive and bellcrank then goes through the transom inside a large rubber hose up to the engine. seems pretty simple.

No gasket...just goes up through a tube into the engine compartment. At the top of the tube there is a small bellows. That needs to be on there to keep water from splashing into the bilge area.