OMC Cobra shift adjustment question?

[Handegard]

I have the procedure for the Transom Bracket Shift Cable Adjustment and it's pretty straight forward.

But what isn't made clear- Is the adjustment procedure done in Neutral? Forward? Reverse?

I'm assuming neutral, but hey, you know what they say about assumptions...

 

[bruceb58]

Re: OMC Cobra shift adjustment question?

What manual are you using?

Everything is done in neutral.

 

[Handegard]

Re: OMC Cobra shift adjustment question?

I am following the directions from

http://www.hastings.org/~stuart/cobra/index.html

He has scans posted. I think I see how I've screwed up my understanding. I was trying to read two scans that he actually has posted not to explain it, but to show how you can do it without the special tools.

I've since read more of his website, and found some more usefull stuff.

The best news is, we manually put my Cobra in forward gear today, and fired it up. It seems to work fine, reinforcing my prior belief that the gears themselves are OK.

Tomorow, we'll check and re-check every adjustment we can find, and I hope to get a trial run in.

Thanks,
Chris

 

[bruceb58]

Re: OMC Cobra shift adjustment question?

The best news is, we manually put my Cobra in forward gear today, and fired it up. It seems to work fine, reinforcing my prior belief that the gears themselves are OK.

Unless you tested it under load in the water, you won't know for sure.

 

[a70eliminator]

Re: OMC Cobra shift adjustment question?

The adjustment proceedure outlined in the OEM manual uses all three forward reverse and neutal positions. The lower cable adjustment at the pivot housing or transom bracket is done in neutral using the alignment plate tool.
Ok thats sounds confusing let me try again. The lower cable adjustment at the transom bracket has to be done in neutral, the upper cable adjustment on the engine bracket uses all gearshift and throttle positions.

 

[Handegard]

Next Question! How to adjust shift rod height on a '88 Model?

Next Question! How to adjust shift rod height on a '88 Model?

Ok, I found what I was initially asking. This guy Stewart's website is pretty comprehinsive, moreso than my manual in some ways....

Anyway, it looks like the "shift rod" is threaded, and can be adjusted by threading in and out further.

Is this correct? Mine is set to almost 7 & 1/2" while it's suppsed to be 7 & 13/64.

I'm just tickled, because our initial diagnosis was that the boat side of the shift mechanism wasn't pulling this rod up high enough. Which is the case, and I figure if I can shorten the rod, the pull the boat has should be sufficeint.

Don't worry, we're going to go all back through the whole system. We've had a taste of "failed gear fear" and we don't want anymore

 

[a70eliminator]

Re: OMC Cobra shift adjustment question?

The shift rod height is adjustable and 7-13/64 is the measurement, adjustment is performed with the upper and lower gearcases separated.
2.3 litre 16-1/16"
3.0-5.8 16-13/16" total length of shifting rod, then 7-13/64 as measured from the very top of the surface of the rod to a point on the machined surface of the lower caseing once installed.

 

[Handegard]

Re: OMC Cobra shift adjustment question?

Thank you for confirming the numbers, I was hoping I'd get that...

That said, I've threaded the shift rod down all the way, and that is only to 7 5/8"

Is my shift rod incorrect? I see no mention of a newer part for that, but I also don't think the rod is stretched...

My friend wants to shorten the rod

Thanks!

 

[a70eliminator]

Re: OMC Cobra shift adjustment question?

You first adjust the overall length to the spec given above 16 and something inches, that length adjustment is done at the other end with the fork and jamb nut.

 

[Handegard]

Re: OMC Cobra shift adjustment question?

When you say you adjust the "over all length" do you mean you measure the entire rod, and shorten it accordingly?

OK- My interpretation of the second part of your statement-

In the top of the shift rod, where it enters the "block" that has the "V" in it to tug up or pull down the rod, are you saying that the collar I see is a form of wedge (jam nut) and that I can use a fork to pull it out, and slide some more o the rod into the "block"?

 

[a70eliminator]

Re: OMC Cobra shift adjustment question?

The block with the "V"' is threaded to the shiftrod and held with a jamb nut, if you loosen the jamb nut and spin the v-block, you can change the overall length, the length for your 5.0 is listed in my previous post.
And yes you measure the whole rod from tip to tip block and all.

 

[Handegard]

Now I have forward and no reverse...

Now I have forward and no reverse...

Good news bad news....

The number I was using for my shift rod height is either wrong, or my interpretation of the process is way off.

I used 7 13/64" over and over again. From the bottom of the machined surface (not the shifter cover) to the top of the rod, I have as close to 7 13/64" as I could ever get.

But it's too short. I can see it plain as day when I line it up with the bellcrank on the transom. Right now, the bellcrank is in neutral and the shift rod is in Forward (up)

If I stick the bellcrank into reverse (down) it'll push down on the shift rod just enough to hit neutral...

I have a 1988 Cobra on a 5.0. Is 7 13/64th the correct number for this year/model?

Thanks,
Chris

 

[a70eliminator]

Re: OMC Cobra shift adjustment question?

Well now that rod height is there, everything will have to be persuaded, put the shift lever in neutral attach the line up plate tool that captures the shift rod, your shift rod should be fitting at this point. I'm kinds drunk right now so later,

 

[Handegard]

Re: OMC Cobra shift adjustment question?

The problem is, my shift rod is now too short.

It IS at 7 13/64" as measured from the lower most portion of the casing to the top of the "block"

I am wondering if I mis-interpreted what surface I should be measuring from. Any other surface that I could measure from would have netted me a higher rod...

For tomorrow, my friend will be taking it out on the lake. I've used reverse in the past, I know it's good. If Forward works tomorrow, we'll take the time to re-do everything. If not, I'll park the boat untill I get gears

Oh, and I'll be taking my Glassmate out to use as a tender for the Bayliner. I'll tow him into shore, so the lack of reverse shouldn't be a problem for a quick test run...

 

[a70eliminator]

Re: OMC Cobra shift adjustment question?

Ok, here's a photo for reference, measure from the bottom edge of the square exhaust opening down 3" and thats where you should be measuring from, in neutral position you'll have approximately 3/4" from the top of the block to top edge of the square exhaust opening, I'll bet your about 3/4" too short because you measured without separating the lower from the upper unit and measured off the wrong surface? Also notice the jamb nut just below the block.

 

[bruceb58]

Re: OMC Cobra shift adjustment question?

I am wondering if I mis-interpreted what surface I should be measuring from. Any other surface that I could measure from would have netted me a higher rod.

Post a picture of how you measured. It's too bad that you even touched this unless you were unsure if anyone had messed with it before. I never touched the shift fork when I used to change cables in my Cobra years ago. The only other critical adjustment is the bellcrank. You want it setup at the 90 degrees.. When it is set at 90 degrees it will slip perfectly into the shift fork. If you are slightly off, you will need to mess with the adjustment up at the engine.

The whole idea of getting the shift fork adjusted to the bellcrank at 90 degrees is so that there is equal throw of the bellcrank for both reverse and forward. If you have the shift fork in the wrong position, the bellcrank will be off from center at neutral thereby causing the unequal throw.

 

[Handegard]

Re: OMC Cobra shift adjustment question?

Ok, here's a photo for reference, measure from the bottom edge of the square exhaust opening down 3" and thats where you should be measuring from, in neutral position you'll have approximately 3/4" from the top of the block to top edge of the square exhaust opening, I'll bet your about 3/4" too short because you measured without separating the lower from the upper unit and measured off the wrong surface?

I will try to take some pictures when I get it back off, that show what I did. I am sure I must have measured wrong, I thought I understood the directions that I had, but now I'm really thinking I didn't.

Post a picture of how you measured. It's too bad that you even touched this unless you were unsure if anyone had messed with it before. I never touched the shift fork when I used to change cables in my Cobra years ago. The only other critical adjustment is the bellcrank. You want it setup at the 90 degrees.. When it is set at 90 degrees it will slip perfectly into the shift fork. If you are slightly off, you will need to mess
with the adjustment up at the engine.

I will try and get some pictures. If I can describe it, I had the upper and lower apart, and there is a plate on the lower that the shift rod goes through which is held on with 6 bolts. I was told NOT to measure of this, and to measure off the surface of the lower itself. So I measured off the recessed portion of the lower, right next to the aforementioned "shift rod plate" I will see if I can take pictures in the next day or so, I'll probably try and get it off again tomorow.

The whole idea of getting the shift fork adjusted to the bellcrank at 90 degrees is so that there is equal throw of the bellcrank for both reverse and forward. If you have the shift fork in the wrong position, the bellcrank will be off from center at neutral thereby causing the unequal throw.

Yeah, I understand this part. It really makes perfect sense, but I didn't think to check how the shift rod mated with the bellcrank BEFORE adjusting it. I just checked it because "hey, it was off, why not check" and when I got a number that was wrong, I went "hey, we need to adjust this"

Only after getting it back on the boat, did I notice that it didn't line up with the bellcrank.

 

[a70eliminator]

Re: OMC Cobra shift adjustment question?

Yep, you measured off the wrong surface, the machined surface is what you should have measured from, it's the mating surface like where you would put the gasket if there was one (which there isn't) between the upper and lowers.
Cross you fingers that your friend isn't going to blow out the gear because he's going to have trouble.

 

[Lou C]

Re: OMC Cobra shift adjustment question?

See if this pic works.....

 

[bruceb58]

Re: OMC Cobra shift adjustment question?

Lou, those are tough to see. Anyway of scanning them at a higher resolution? I don't have my Cobra manual anymore otherwise I would do it.