OMC Cobra issues

[whl2c]

I have a few issues and have turned once again to iboats for help! My boat is a 1986 omc cobra w/a 4.3L V6. I do have an OEM manual, which is definitely lots of help when it comes to tearing things apart, but doesn't seem to troubleshoot the problems I am having.

1. My boat is taking on water. I just replaced the u-joint bellows and the exhaust bellows at the beginning of the season and both are still intact. Something tells me that the water is not coming from the u-joint bellows because my l/u oil is NOT milky. When I pulled the boat out of the water yesterday (with quite a lot of water in the bilge), I noticed water leaking out of the water hose that goes from the transom to the upper gearcase. I haven't replaced this hose and it does seem cracked. Could this be the source of my leak? If this is the hose that brings water in for cooling I can't imagine how its getting into the engine compartment. Could it be something as simple as a bad seal around the outdrive. The water comes in no matter what tilt position the trim is, whether the boat is running or not, and no matter what the speed of the boat is. And yes, I do have the plug in 8)

2. I am aware of the shift cable issues for this model and have read stuart's website. My boat goes in and out of gear okay.. no grinding or any noises whatsoever. The only problem is that my shifter is really stiff around neutral. Once I can get the shifter out of the twelve o'clock position it easily goes into forward. I do sometimes have problems coming out of reverse and have to move the shifter a little past twelve o'clock towards forward to disengage reverse. Maybe I'm just dense but my thought would be that for me to be ruining the gears, there would have to be grinding or hard/loud shifting. But stuart does say that a properly adjusted cobra shift cable should shift with a finger. Am I ruining my cobra?

Thanks!!!!!

 

[cobra 3.0]

Re: OMC Cobra issues

I have an '86 boat and 3.0 cobra. Mine leaked from the gimbal housing. The transom may be soft from water leakage over time. I tightened mine up from the inside and all is ok...for now. I understand that my transom wood may be rotten around the holes, but I am not ready to start changing the wood out of a transom on an inboard!!!:|

 

[Boatin Bob]

Re: OMC Cobra issues

Just because your lower unit lube is not milky doesn't mean that your drive shaft bellows can't be leaking, there are seals to prevent water from getting in there and the lube from coming out. If water is coming in whether the engine is running or not that is serious and needs to be checked right away. Could be loose transom mount as cobra suggested or even soft transom (boat is the right age for that)

 

[Don S]

Re: OMC Cobra issues

Just because your lower unit lube is not milky doesn't mean that your drive shaft bellows can't be leaking, there are seals to prevent water from getting in there and the lube from coming out.

While there is a seal in the drive to keep the gear lube in the drive, it is only a single liipped seal and will NOT keep the water out of the drive. That is the job of the bellows.

There is any number of things that can cause water to get into the bilge, not all of them has anything to do with the outdrive, transom shield or anything else.
Any thru-hull fitting could be leaking. Vents could be allowing water in.
If you have used the flashlight and mirror method and even tried the talcum powder method to find the leak. Next step is to pull the engine, put the drive back on. Tie the boat to the trailer and back it into the water and look very carefully. You may have to cap the exhaust Y so water won't come in, but while it's in the water you can sit down where the engine used to live and see under everything.
I've used this method many times. On OMC's, I have usually found problems with exhaust Y's being corroded or the lower bolt tabs broken off.