How can you tell when its time to overhaul OMC Outdirve?

[rybad]

1989 OMC 350/5.7 Cobra (two).<br /><br />I've had this boat for two years, and have changed the gear oil every fall since. Everytime, the used oil starts out slightly milky, but then flows brown, and does not smell burnt. The magnets have some metal, but mostly like metal dust as apposed to shavings.<br /><br />The only problem I have with the drives is extremely hard shifting, which I know OMC is famous for (thats next spring's project). Other than that, they seem to run fine. I do pull them off to lube the gimbal bearing and shaft too.<br /><br />Last spring, I replace the starboard engine, and since then, I notice a slight rolling vibration and when idleing out of the marina, that engine makes a faint huming noise when I put it in gear (not sure if its coming from the outdrive or what.. I assume it is) The port side does not make any humming sound.<br /><br />(I did use the alignment tool when replacing the engine/drive)<br /><br />-David

 

[tommays]

Re: How can you tell when its time to overhaul OMC Outdirve?

david<br /><br />there is only one way to check the drives as far as the slight milkly oil when you pull them for PM they need to be pressure and vacume tested for leaks<br /><br />the fill gaskets should not be reused and are the simplest place to have a small leak after that it would be and oil seal somewere in the upper or lower drive <br /><br />i think the OMC guys here can help you make them shift correctly<br /><br />tommays

 

[Don S]

Re: How can you tell when its time to overhaul OMC Outdirve?

I don't think you are due for an overhaul, but a very minor leak in a drain plug gasket is very common when the gaskets get reused as Tommays mentioned. The pressure/vacuum check would be a good thing to perform the next time you drain the drive.<br />

The only problem I have with the drives is extremely hard shifting, which I know OMC is famous for (thats next spring's project).

Sounds like you may have a problem with a shift cable or the ESA system, here's a link you can use for reference.<br /> OMC Tech Info <br /><br />

I notice a slight rolling vibration and when idleing out of the marina, that engine makes a faint huming noise when I put it in gear (not sure if its coming from the outdrive or what.. I assume it is)

When you pull the drive off, check the gimbal bearing, if it the slightest bit rough when turning, that would cause the hum.

 

[cc lancer]

Re: How can you tell when its time to overhaul OMC Outdirve?

When you pull the drive off, check the gimbal bearing, if it the slightest bit rough when turning, that would cause the hum.<br /><br />Hey Don, you reckon a split in the bellow could cause water to get to the bearing, make it rust and cause a hum.

 

[Don S]

Re: How can you tell when its time to overhaul OMC Outdirve?

Well, the "hum" could be the first stage of that bellows split, the second stage would be a loud rumble, third stage would be a loud roar, forth would be the crashing and banging of large parts disassembling themselves at high rpms causing a great amount of $$$$$ leaving the savings account.

 

[Lou C]

Re: How can you tell when its time to overhaul OMC Outdirve?

BTW, if it shifts hard it is either not in proper adjustment or you need to replace the transom shift cable. Hard shifting is not normal on a properly set up Cobra drive. See the link Don provided, it tells you all you need to know.