Sundancer 240 with 5.0 MPI overheating, Help.

[altouchet]

I just purchased a 2007 240 Sundancer with 5.0 MPI/Bravo 3. It has 100 hours. It was at a dry storage marina all it's life. Everything was fine until a few days ago. It started overheating. I have replaced the entire sea water pump even though it did not look bad when removed. I had heard the brass pumps were bad about scoring on the bottom and lid from impeller/sand wear.I also replaced the thermostat. The temp is fine, 160 degrees or so while idling in the slip. However, as soon as we run in gear with a load, it begins to overheat. The overheating can be reduced by revving the engine in neutral, as if there is an issue with getting enough water flowing thru the engine. I have heard about a possible problem with obstruction in the bravo 3 transom assembly, but have not been able to confirm this. When I removed the water pump while the boat was in the water, there appeared to be a good flow of water into the boat from the hose that connects from the drive. Any ideas?

 

[Georgia SeaDawg]

When were the manifolds, risers, and elbows replaced? I had a similar issue with my 07 240.

 

[altouchet]

The risers, manifolds, and elbows have not been replaced. The boat's history is in brackish water, so I know that is a possiblity.
I was just thinking since it has only 100 hours, maybe it's another problem.
Did the overheating issue start all of a sudden before you changed your manifolds and risers, or was it a gradual issue of the engine running hotter, and hotter?
Mine ran no hotter than 165 for the first few weeks I owned the boat, then suddenly one day it over heated, and has been doing so ever since.

 

[Georgia SeaDawg]

I had no prior issue with temps. Coming back to the marina one afternoon, I noticed the temp climbing, and then the alarm went off. No prior warning or temp issue.

 

[sweet revenge]

Did you check to see if the old impeller in the sea pump , was intact or was it missing any of the rubber veins? If it was missing veins you need to check your thermostat housing and your power steering oil cooler for blockage due to imbedded pieces off rubber, which will restricted flow. If that's okay , try to run the engine out off the water with a hose attached and check the amount off water coming out off your exhaust ports, if one is more than the other, your manifolds are clogged and you need to replace them. The risers should be replaced every two years.

 

[jason78]

What kind of H20 PSI are you seeing on the Smartcraft LCD gauge?

 

[altouchet]

Thanks for your replies. My Water pressure is about 1.0 - 1.2 at idle. At 4000 rpm its between 7.0 - 9.0. What should it be? The impeller was perfect when I removed the water pump. Service records indicate it was changed in 2011 before I bought the boat. The brass pump was scored a bit on the lid, so I changed the entire pump assembly with a new aftermarket stainless pump with replaceable wear plates.

 

[scoflaw]

After 7 years in salt the manifolds and elbows are done, with a raw water cooled system, regardless of hours. Once dipped, they will continue to corrode whether your using the boat or not. Pull, inspect and confirm. Replace your shutters while your there

 

[KP49]

Thanks for your replies. My Water pressure is about 1.0 - 1.2 at idle. At 4000 rpm its between 7.0 - 9.0. What should it be? The impeller was perfect when I removed the water pump. Service records indicate it was changed in 2011 before I bought the boat. The brass pump was scored a bit on the lid, so I changed the entire pump assembly with a new aftermarket stainless pump with replaceable wear plates.

I get about 2psi at idle and 10psi at 4000rpm, when my transom was corroded and inlet hose was pinched about 60% I got about 1/2 that for water pressure but it still never overheated or ran hot.

My boat spent 2.5 years in saltwater before being using in freshwater the rest of the time. I've had the elbows and risers off and they look fine inside. The newer style dry joint risers and elbows dont corrode away at the gasket surface like the older ones and they can last a lot longer - but they can still get clogged with rust and salt water is tough on them. Simple enough to pull the hoses off the risers and manifold and flow some water into the riser and see how easy it flows out the manifold - should be almost no restriction.

Since you have decent water pressure something major is going on if it overheats that quick, it could be the manifols/risers are gone. There are also some check valves on the bottom of the manifolds the direct the water fllow to the manifolds that could get stuck (part of the single/three point drain system) if you look at the water flow diagram they could cause problems if stuck open.

FWIW my sea water pump cover is scored pretty bad and it still works fine. I'm going to put a stainless wear plate in when I swap impellers in the spring, new pump cost is crazy..