Cobra drive Clunks after shifting

[Bigmike3491]

So I realize this post is quite old.........but, I just bought a 1988 Bluefin Sportsman 1950 and it is said to have this same problematic the above original post. I havent tested (afraid of causing more damage). I’m just taking the original owners and his sons word. The son is a very good friend so I believe him fully. Just wondering about the cost (relavent to this decade) of a shop to diagnose and repair. I am an absolute newbie in every way, First boat and first problem to overcome. So thank for any and all help and advice you can send my way.

By the way I was practically given this boat for a song......... and 500.00 dollars. So there is some wiggle room for it to be cost effective. Thanks again

 

[Bondo]

Just wondering about the cost (relavent to this decade) of a shop to diagnose and repair. I am an absolute newbie in every way,

Ayuh,...... Welcome Aboard,...... Yer about to find out, that mighta been the worst $500. you've ever spent,....

OMC has been outa business for Decades,....
The biggest Problem will be findin' somebody to work on it, 'n if ya do, parts can be a problem,.....

Others will be along with more complete knowledge 'bout the OMC Cobras, but yer probably gonna have to do the work yerself,.....

 

[Redrig]

Its not all doom and gloom , at least you have a Cobra that you may be able to just convert to an SEI outdrive .

try to fix yours but if the cost approaches anywhere near 1k , look into the SEI outdrive swap .

us older OMC owners dont even have that option and have to keep our stringers alive .

 

[Lou C]

Well as Bondo said, your problem may be in finding a shop that knows the Cobra and is willing to work on it. The problem you have there, is a result of sticky shift cables, or a shift system out of adjustment that caused the dog clutch to not engage all the way and then engine torque causes it to jump out of gear. Then the edges of the clutch dog and the fwd/reverse gears get rounded off (they are supposed to be sharp and squared off) and it won't hold in gear.

Your plan of attack should be to first get the entire shift system gone through and have it set up by a pro, this includes:
remove the drive
set shift rod height
clean out bell crank pocket in the pivot mount
measure transom shift cable drag
adjust shift cable with drive off
adjust remote cable with drive on
make sure shift system as equal throw in fwd & reverse
make sure ESA system works, or you will have trouble shifting to neutral
make sure engine idle is not set too high, and that it will reliably idle at about 550 rpm in the water

if it still jumps out of gear after this, then you most likely need a lower unit rebuild with new clutch dog, fwd & reverse gears.

I have had one for 15 years and had the not shifting to neutral issue early on. It was set up by a good OMC trained shop and then was fine for a long time. I had a few issues about 8 years after that and learned how to adjust it myself. Still fine.
The Cobra was a good product that was mis-understood. They were better than Mercruisers in some ways:
1 ) easier bellow replacement
2) much easier impeller replacement (15 min job)
3) not prone to the worn hinge pins and rusted steering arm bolts and transom leaks that older Mercs seem to have.

 

[Keaton]

Its not all doom and gloom , at least you have a Cobra that you may be able to just convert to an SEI outdrive .

try to fix yours but if the cost approaches anywhere near 1k , look into the SEI outdrive swap .

us older OMC owners dont even have that option and have to keep our stringers alive .

I swapped my lower unit to a SEI unit and haven't had any problems with it. came with a 3 year no fault warranty, you have to flush the oil after like 8-10 hours. The card in the box tells you.
what I bought
https://www.**************/OMC_Cobra_Lowers.html


SEI also carries a Cobra to Alpha conversion. its a alpha out drive (their version) and a special gimble that adapts the 2 different units. IIRC these also have a 3 year no fault warranty on them.
adapter
https://www.**************/Cobra-Conversion-Kit.html

Gen 1 Unit
https://www.**************/Mercruiser...-Complete.html

Gen 2 unit
https://www.**************/Mercruiser...-Complete.html


not sure of the difference between Gen 1 & Gen 2 someone here does though, sure of it.


if you google for the shop manual you can find it in a PDF version for free. I printed it at work and put it in a 3 ring binder plus i keep a PDF version on all my computers and on my phone.

https://sunbirdcorsair.wordpress.com...in-pdf-format/