We have a 1987 34' sea ray express....

[loobjob]

We have a 1987 34' sea ray express. The boat has 454 sea water cooled motors with about 1000 hrs each. The port side of the port motor overheats every time we go out. I have changed the riser, manifold, impeller, thermostat and boiled out the transmission coaler heat exchanger. The starboard side of this motor is just fine. Could it be the head is blocked for the muffler is not allowing water out?

I can't figure this one out. Would appreciate any help;

Thanks

Pat

[wingless]

The port side of the port motor has a new manifold, riser, knuckle and slotted gaskets for the raw-water cooled exhaust system, correct?

Is it just raw water cooled exhaust w/ anti-freeze cooled block, or is everything raw water? Is this a fresh water or salt water boat?

If so, then how is the raw water flow to the manifold w/ the hose disconnected?

How is the interior of the raw water hoses feeding the manifolds?

Was the raw water circuit cleaned after changing the impeller? Was the damaged impeller reassembled on the bench to ensure all the fragments were located?

Is the raw water drained, flushed w/ fresh water, then flushed w/ Salt Away after each use, then stored w/ a dry exhaust?

[loobjob]

It is just raw water cooled no closed system with anti freeze. The impeller was not missing any rubber parts and we did backflush it to see if there were any from previous problems.We did take off the hose and check the flow of water for the port side and it seemed ok. Most all hoses have been replaced.

[wingless]

Were the exhaust knuckles replaced?

Were the exhausts on both sides of the engine replaced?

[loobjob]

I am not sure what you mean by the knuckles.
But we only replaced on riser and manifold.

[wingless]

The site calls it an elbow.

http://www.ebay.com/itm/Genuine-OEM-MerCruiser-Exhaust-Elbow-5-0L-5-7L-1983-2002-807988A03-/350957772493?hash=item51b6b69ecd:g:VocAAMXQgPFRHRdX&vxp=mtr

Were the exhausts on both sides of the engine replaced?

[fwebster]

On seawater cooled engines, the complete water jacket has seawater in it. Over time, rust particles build up in the skirt of the block and eventually block cooling water flow. The quickest way to test this is to remove the engine block drain on the hot side and see if water drains out. If it doesn't, then the chances are good that the block is full of rust.

Unfortunately, there isn't a fix for this problem because even vatting an engine will not remove the accumulated rust once it builds up. So, the bad news is that if the block is full of rust and scale, you are probably looking at a re-power here.

From your question it seems as though you changed the exhaust castings in an effort to remedy the one-side over heating. However, if the engine cooled properly, then you changed the manifold and riser on the offending side, check to see that you used the latest riser to manifold gasket from Mercruiser (there have been several different designs in an effort to remedy failures) and that the gasket is installed correctly.

Good luck with it..............

[loobjob]

Thank you much for your help