Re: Need help on overheating problem and how to fix it (OMC Cobra)



In article
<1124129144.937308.196290@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
melandre@xxxxxxxxx says...
> Hello, I have an older 1990 Bayliner with an I/O OMC Cobra 2.3L.

I don't consider myself an expert, but have the same drive
and may have some ideas.
>
> Problem: Over the last few weekends, the temperature goes way up when
> I start the boat (in the 200 to 250 range) and after a random amount of
> time (usually 1 to 4 minutes), it suddenly drops back to its normal
> range (around 125-150).

I concur it may be a thermostat, BUT, it could also be the
impeller (on the stern drive). If the boat has ever been
run with the drive out of the water (or without a STRONG
flow from a flush tool) for 15 seconds or more, I'd suggest
the impeller melted down.

It's easy enough to check, either in or out of the water (if
out, be sure to use a flushing tool with a strong flow of
water).

Remove the sloped cover on the top/rear of the stern drive
(3 bolts). The round "cup" you will see near the top with a
small hose coming out of it is the impeller cover. Make
sure you have cooling water present and fire up the engine.
There should be NO water escaping from the area of the
impeller cover. If there is, you've melted down the
impeller. The cover is easily removed by taking out the
three obvious bolts.

Buy a complete rebuild kit INCLUDING the cover, replace it,
and be done with it.

>
> 1) Drain the engine block and exhaust manifold. (Do they mean the water
> only? Can I do this with the boat in the water?)

Yes, Yes. Look for small diameter clear, yellowish hoses on
the starter side of the engine. Follow them up to the drain
valves.
--
Mark

The truth as I perceive it to be.
Your perception may be different.

Triple Z is spam control.
.