'94 OMC shutting down after 30 min

[John7676]

Hi
I have a 1994 302 Four Winns Cobra OMC We have been having trouble with it wanting to take a rest after 35-45 minutes in the water. And after given it a rest it will start back up and run great for another 35-45 minutes and all over again. Any suggestions as to what it might be?
Frustrated in Austin Texas.

 

[southkogs]

Started you a new thread John ... you were kinda' hijackin' the other one.

Is it overheating?

Welcome aboard.

 

[John7676]

Thanks so much for the response. Will it hits about 225 at full throttle but when in ideal mode it is fine hits about 160 for a good 25 min I put the ears on it today and it was fine. Just when we hit the water that it heats up and cuts off

 

[southkogs]

Sounds to me like yer' overheating ... I don't know the Cobras well, but when was the last time you changed the impeller?

 

[Sparkinator]

Is it a Cobra or Cobra SX? In 94 they were transitioning from the old Cobra to the SX. The old Cobra has the flat top on the drive. The water pump impeller is in the lower unit.

Or does it have the hump on top of the drive? If it does, then it's basically a Volvo SX drive, and the raw water pump is belt driven off the crankshaft. Everything on it is the same as a Volvo.

I've had mine, (belt driven SX) overheat if my belt wasn't tensioned enough. It would slip just enough to not allow proper cooling at higher rpm's.




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[John7676]

I will check the belts today. I replaced the impeller and still doing it. I was told maybe it's the coil and purchased a 12 volt yesterday so gonna put that on today.
It's the it looks to me like it may be the SX.

 

[Sparkinator]

If it's an SX, then I've got some manuals to share, they are Volvo, but are identical to your drive.

http://www.4shared.com/office/eMAEnxXX/HU_Early_NC_Fuel_Systems_77888.htm

http://search.4shared.com/q/1/hu sx drive 7788851?view=ls&suggested

http://www.4shared.com/office/YhKe25kC/HU_early_NC_Engine_Manual_7788.htm

They are pdf files that are downloadable and have helped me a lot. They aren't torrents and are virus free. Our old moderator DonS uploaded them years ago and they have helped numerous people.

It's kinda confusing when talking about OMC Cobra's, because the model previous to the SX, (the Cobra) had a lot of issues that were corrected with the SX. My OMC Cobra is a SX, and don't even call it an OMC any longer, just to avoid confusion. You technically have an OMC, but because OMC is now obsolete, it's easier to get correct responses by knowing that it's Identical to the Volvo's.

The old Cobras had a different way to fill oil in the outdrive, adjust shift cable, change raw water pump impellers, etc.

Hope this helps.