1988 Sunbird Go no GO

Joined
Aug 8, 2013
Messages
13
Hello, this past weekend I was on the lake in my 1988 Sunbird with a 4.3 OMC Cobra in it and while pulling a tuber the boat I thought cavitated so I let of the throttle. When I went to go again the boat acted like a clutch was slipping. The boat would go forward at just a bit above an idle but, anything more than that it did its clutch slipping thing. It goes backwards fine and does engage into forward with no clucking. I am somewhat mechanical but have not done a lot with boats. Can someone please give me a direction as to where I should start looking? The boat in years past has pulled tubers and skiers for hours with zero problems. We had done several hours of casual cruising prior to pulling the tube this last weekend and the slipping issue occurred after maybe about an hour of pulling the tube. Thank you in advance.
 

southkogs

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Jul 7, 2010
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14,785
Welcome aboard:

If you can idle along with no real trouble, but when you give it some throttle it feels like it's doggin' out - maybe your prop hub is spun. That would be the easy solution.
 
Joined
Aug 8, 2013
Messages
13
Thank you Southkogs for the warm welcome. That is something I hadn't thought of. The boat bogs but the engine winds up. I am guessing with engine off and the boat in gear the prop possibly could be spun by hand then if that is the problem. I will also pull the prop and look it over. That will be an after work today project.
 

southkogs

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Jul 7, 2010
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14,785
Not sure how the Cobra hubs work, but turning it by hand won't tell you.

Inside your prop is something like this:
320322_2.jpg

If you can see where the edge of the hub is, and the edge of the prop itself: make marks on both that align with each other. (Not what you have, but gives you the idea)
upload_2017-2-5_20-6-12-png.34560

Then take the boat for a spin and try to get it on plane. (Have a plan to get back in too ;)). If those marks don't align, you've found a spun hub. You can replace the hub (or have it replaced).
 
Joined
Aug 8, 2013
Messages
13
Well got home from work and went right to shed. You are correct that the prop turned by hand told me nothing. I took the prop off and small pieces of rubber fell out and when I turned the prop over you could see that the rubber core was not as it should be. The prop is an aluminum factory prop that has already had the blades rebuilt and is showing its age so, I think I will shop for a new prop. Thank you again for the help with my boat. Not very often do I get an easy fix on my old toys. May your sky's stay blue and your waters calm!
 
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