OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

[HighLineCBR]

Hi all,

So i finally pulled my 1989 OMC Cobra outdrive which is mated to a 5.7L Chevy 350.

My original problem started with not being able to shift into reverse. disconnected the lower shift cable at the top and tried to switch by hand to eliminate some of my suspicions. Shifted fine into Forward and Neutral. Could not push it into Reverse manually. After i took off the cable I eliminated that this could be a shifter problem.

SO when i pulled the drive... here's what i found. Enjoy the pics!

Apparent hole in the Drive shaft bellow, with visible water intrusion. (I'm surprised it never leaked into the bilge). Rusted and SHOT gimbal bearing as well as shot u-joints.

GIMBAL

U-JOINTS

Also found that the right under the exhaust bellow i have a hair line crack in the housing. Could this be a problem? Technically water comes out in that chamber anyway with exhaust.

CRACK

When I look into the exhaust chamber i see a weird rubber flap like piece just laying there. Its not attached to anything and I cant get it out because its bigger then the hole it needs to pass through in order to come out. I'm thinking it was meant as a valve not to allow water to come back in but only to let water out with exhaust. But why would it not be attached in any way? Should it be?

Rubber "flap"

Take a look at the gimbal bearing pic below. In order to take this out do i need to remove the lip marked with the red arrow frist? It looks like it could be a screw in looking at the cut away top and bottom sections. But not sure. Or do i just pull the bearing out at this point as is? Please advise on this.

Gimbal Bearing

LASTLY
Instead of rebuilding this outdrive, which i will have to do again... (just rebuilt last year). I'm contemplating putting on a brand new ALPHA ONE, well the SE116 from www.Sterndrive.cc with their new OMC adapter kit. is it worth it? Brand new and with 3 year warranty. WIll it work well with the OMC thou?


lots of info here in one post but hope you can find your way around and help me out by answering my questions above.

thanks!

 

[bruceb58]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

Don't worry about the crack near the exhaust bellows.

That weird rubber thing you see in the exhaust is your exhaust flapper. you need to get it out of there and replace it.

How do you know you need a new drive? Can you manually shift it with the shift fork?

Do you have water in your drive oil?

The gimbal bearing just pulls out.

 

[PS94]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

The red arrow part comes out with the bearing.

 

[Challenger84]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

i plan on replacing my bearing too and this thread would help me out a lot.

 

[a70eliminator]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

So far none of the pictures would indicate a problem with shifting the drive and your so far I don't see anything that would discourage me from continuing on with the maintainence, replace bellows, remove the broken flapper and leave it out, so now with drive off can you shift it into reverse?

 

[HighLineCBR]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

thats encouraging. The drive will not shift into reverse manually when pulling on the shift rod. It's impossible to push downward, which would engage the reverse.

This leads me to believe that the lower unit gears are shot, definitely the reverse gears. Not sure if I can replace just the reverse gears or do I have to replace all of the gears at once? New gears alone will cost me half as much as the new SEI setup.

My reasoning behind getting the SEI drive conversion tot he Alpha One is as follows:
1) Cheaper in the long run
- SEI complete package will cost $2000
- I can probably get 1000-1200 for my CObra drive as is on ebay or craigslist
- Entirely brand new unit with the SEI
- 3 Year warranty

The Cobra is old and i I just had it rebuilt last year. Shouldn't have to rebuild it again in my opinion. Same problem could happen in a few months or sooner. Plus i plan to keep my boat for the next few years and the OMC is getting harder and harder to get any parts for and to work on or find knowledgeable people for advice.


EXHAUST FLAP
how was this installed originally? does anyone have a picture of this in the manual? I would imagine that to reinstall it i would have to take off the entire transom mount? Can i just take it out and not use it anymore?

 

[sea wolf]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

thats encouraging. The drive will not shift into reverse manually when pulling on the shift rod. It's impossible to push downward, which would engage the reverse.

This leads me to believe that the lower unit gears are shot, definitely the reverse gears. Not sure if I can replace just the reverse gears or do I have to replace all of the gears at once? New gears alone will cost me half as much as the new SEI setup.

My reasoning behind getting the SEI drive conversion tot he Alpha One is as follows:
1) Cheaper in the long run
- SEI complete package will cost $2000
- I can probably get 1000-1200 for my CObra drive as is on ebay or craigslist
- Entirely brand new unit with the SEI
- 3 Year warranty

The Cobra is old and i I just had it rebuilt last year. Shouldn't have to rebuild it again in my opinion. Same problem could happen in a few months or sooner. Plus i plan to keep my boat for the next few years and the OMC is getting harder and harder to get any parts for and to work on or find knowledgeable people for advice.


EXHAUST FLAP
how was this installed originally? does anyone have a picture of this in the manual? I would imagine that to reinstall it i would have to take off the entire transom mount? Can i just take it out and not use it anymore?

I think It's a no brainer, especially if u can sell the OMC for what you said. Not only will you eliminate the hassles of dealing with an OMC, but the SEI will increase the resale value of your boat.

 

[jerryjerry05]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

The shift mechanism which you didn't show.Is probably gummed up.The bellcrank needs lots of grease and cleaned every year.The flapper thing in the inside.Goes at the top of the exhaust,by the risers and the Y tube.
I'd get the kit and get rid of the OMC.J

 

[HighLineCBR]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

Will the SEI116 (essentially the Alpha 1 unit) be able to handle the size and weight of my boat? its a 23 ft cuddy cabin with a 5.7 L, 260HP motor.

According to the SEI specs their drive is rated for up to 300HP. Just curious if its a reliable product.... but then again it must be since they are offering a 3 year warranty on it.

 

[bruceb58]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

The shift mechanism which you didn't show.Is probably gummed up.The bellcrank needs lots of grease and cleaned every year.

He says he can't shift it with the drive off so the bell crank is no longer in play.

 

[HighLineCBR]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

thats correct. I've eliminated everything except for the drive for the shift problem.

I can manually pull the shift rod up for FORWARD but will not go down for REVERSE. its definately the lower unit.

 

[Lou C]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

try this...have someone turn the drive shaft when you are trying to push the shift rod down....these things usually shift better when there is turning torque applied to the gears and in fact the OMC manual says not to shift them with the engine off...

take a look at this vid...they have the upper unit off but you can do the same thing with someone turning the driveshaft clockwise (the way it normally turns with the engine running)

http://www.youtube.com/watch?v=vuAcrDFvApA

 

[zbnutcase]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

Yup SEI time, and attach the anchor chain to the OMC....

 

[Howard Sterndrive]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

that crack made the sale on the SEI conversion, imo

 

[HighLineCBR]

Re: OMC DRIVE OFF - Visible problems - with pics - take a look and HELP

UPDATE

completed the SEI conversion myself. I didnt think it was hard at all. If you're a little mechanical anyone can do it. I also replaced my gimbal bearing with a slide hammer rented from AutoZone for free and a home made bearing driver. not too hard... I did have to replace the shifter control unit to a teleflex model to get the shift cable throw reversed. That was a bit of a pain in the ^@$ because of the tight space to work in.

so far put about 15-20 hours on the new unit. Havent changed the oil yet but planning on it soon. The boat runs great. I really love it. No vibrations, no shaking, gets on plane nice and quick.

Another happy SEI customer.