Overheating Problem?

[finke_86]

I have a 1988 bayliner cobra 2250 with the cobra outdrives. Last year it never overheated but didn't shift right. So last week I replaced the shift cable and while I had the outdrive off I split the case and adjusted the shift rod. When we put everything back together and took it out today it started overheating while trolling around in the cove but when I sped up it cooled down quite a bit. I am kind of a newbie so not sure what it is but I know it's not the impeller. Thanks for any help.

 

[cr2k]

Re: Overheating Problem?

How do you know it's not the impeller? Have you changed it lately? They require changing every 2 years.

 

[finke_86]

Re: Overheating Problem?

I took it apart and checked it and it looks good

 

[Howard Sterndrive]

Re: Overheating Problem?

verify the temp with your hand - see if the manifolds are hot to the touch - thermostat housing too - etc...
could be a gauge/sender issue

generally low rpm heat is flow related - usually impeller, but worth looking through the whole water flow path - replace the thermostat

if you have a power steering cooler, make sure it isn't clogged on the water side. make sure an old failed exhaust shutter isn't laying down in and blocking the exhaust tube/outlet. Check riser to manifold gasket and riser water jackets for corrosion build up.

you can idle it at the dock and take the supply hose loose briefly at the thermostat hsg to get an idea of flow after the p/s cooler - should be similar to a garden hose with the tap half open

 

[finke_86]

Re: Overheating Problem?

It was scortching hot to the touch. When I took the impeller housing apart the impeller looked good but I couldn't get the impeller out of the housing with just my fingers it was wedged in there tight. Is that right?

 

[cr2k]

Re: Overheating Problem?

I have seen many that "looked good" and would not do the job, You can't really start chasing heat issues with very first variable unknown. A cobra can look good and be bad, if the cage has moved even a little bit or there is any melting it IS bad.

 

[finke_86]

Re: Overheating Problem?

I bought a new one tonight. I am going to put it in tomorrow night. When I pulled the outdrive and split it there was a gromet(spelling) on the top of the lower unit that looked kind of melted but this was before it overheated.

 

[Reinell-BRXL-191]

Re: Overheating Problem?

mine looked great! but when I removed it, the blades were all bent over and stayed that way - they need to extend out when they go thru the water jacket areas in the cage... so... since they wouldn't, I had to get the rpm's up for it to catch water and pump... at idle off the trailer, it would overheat... changed the impeller, and it's cool right out of the gate... no such thing as "it looks good"

 

[sea wolf]

Re: Overheating Problem?

I bought a new one tonight. I am going to put it in tomorrow night. When I pulled the outdrive and split it there was a gromet(spelling) on the top of the lower unit that looked kind of melted but this was before it overheated.

If that seal was melted, it needs to be replaced. And that seal has a tendency to fall out when reassembling the 2 halves it the water tube isn't lined up perfectly. That can cause an overheat.

 

[finke_86]

Re: Overheating Problem?

I found the problem just like you said the top seal on the water tube was halfway down the tube. And I replaced all the seals and the guide. I didn't get it all back together tonight but will tomorrow just in time for the weekend. Thanks for all the help.