89 OMC outdrive problem??

3rd Mate

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Aug 4, 2014
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I have a 1989 Donzi with a GM 350 and Cobra outdrive. My concern is that when I first start out, at low speed, I shift into forward there is the usual clunk and then after a few seconds, (about 5-10 seconds ) the is another "clunk". I am not sure what is causing it or why it is happening. It does not seem to affect performance in any way. Could it be a shift linkage issue ?? The clunk seems to be coming from the out drive. Any suggestions, help ?? How do I determine what it si and how do I fix it?
 

jerryjerry05

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May 7, 2008
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18,185
Could be the clutch dog's going.
Could be the shift linkage is corroded or you need a cable.

Remove the drive and check/ clean the bellcrank.
It can/ does corrode around the end of the crank making it very hard to shift.into gear right.
This should be done every year or more.
 

jerryjerry05

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May 7, 2008
Messages
18,185
Could be the clutch dog's going.
Could be the shift linkage is corroded or you need a cable.

Remove the drive and check/ clean the bellcrank.
It can/ does corrode around the end of the crank making it very hard to shift.into gear right.
This should be done every year or more.
Location, profile? You might be close to someone who can help.
 

bruceb58

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Mar 5, 2006
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30,751
It's the clutch dog failing due to a failed lower shift cable. Once they do that clunk while they are in gear, the dog clutches are rounded off and won't hold anymore.
 

3rd Mate

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Aug 4, 2014
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Thank you for your help. I will have to have it checked before I go much further. Since I am not as mechanical as I use to be, I am not familiar with boats and the terms. I understand some. I know there was a problem early on with straight gears that were later modified to 5 degree gears. Any advice where to take it....I updated my location profile. Thank you once again for all your help and advice.
 

bruceb58

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Mar 5, 2006
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30,751
OMC thought their problem of failing clutch dogs was that the mesh teeth didn't have enough angle so they replaced the dogs with a steeper angle to keep them meshed better. Later on they realized it was actually the design of the cable that was bad and they replaced the cables after that. The cables and their adjustment were and will always be the problem with dog clutch failures because as the cables fail, they go out of adjustment and don't let the dog clutch engage all the way.
 
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