Jimmy Buoy
Well-Known Member
- Dec 3, 2008
- 2,471
- Boat Info
- 2003 Cobalt 293
- Engines
- Twin Volvo-Penta 5.0 270hp & DuoProps
Sharing info on CSR has helped me plenty - time for me to share my experience in hopes that it will help others.
Left the marina the other day. Both Merc 4.3 MPI Bravo III's purring well. Ten minutes later running at 3200RPM I hear a SOLID ALARM and the port engine lowers its RPM without me touching the throttles. I get the boat off plane, go into neutral and stop the engines. What the heck!?!
Inspection of the engine room reveals that the serpentine belt on the port engine came off and was laying on the ER floor. That means no Raw Water pump for about 30 seconds @3200RPM. I place my hand quickly on the top of the exhaust risers - too hot to keep my hand on! Damn. The side of the exhaust manifolds are even hotter so no touch! Grab my tool box and quickly reinstall the belt but decide NOT to start up the boat right away since it would introduce cool lake water into the really hot cast iron exhaust manifolds and didn't want to risk cracking the casts. Anchored and enjoyed the beautiful day for a bit!
Two hours later, I went to start the engine. The crank only turned an inch or so and abruptly stopped. Battery voltage was 14vts so it made me suspicious that something was stopping it from rotating. I decided to start pulling plugs starting with #2. It looked suspiciously wet. #4 was dry and #6 when removed released a stream of uncomfortably hot water (about 1/2 a cup). Never had that happen. Removed #1, 3 and 5 on the other head and they were all dry. Spun the starter and water sprayed out of the #2 and #6 plug holes but seemed to be lessening.
Tucked my tail between my legs and putted back to the dock on the stb engine. Sprayed WD40 into all the cylinders there and spun it again just to try and protect the internals from rust.
I'm thinking Head Gasket or Cracked Head (from overheating) and am ready to pull the boat and start working to remove the "wet head" but decide to go and buy a compression tester first just to see what I'm working with here.
Any ideas???
Left the marina the other day. Both Merc 4.3 MPI Bravo III's purring well. Ten minutes later running at 3200RPM I hear a SOLID ALARM and the port engine lowers its RPM without me touching the throttles. I get the boat off plane, go into neutral and stop the engines. What the heck!?!
Inspection of the engine room reveals that the serpentine belt on the port engine came off and was laying on the ER floor. That means no Raw Water pump for about 30 seconds @3200RPM. I place my hand quickly on the top of the exhaust risers - too hot to keep my hand on! Damn. The side of the exhaust manifolds are even hotter so no touch! Grab my tool box and quickly reinstall the belt but decide NOT to start up the boat right away since it would introduce cool lake water into the really hot cast iron exhaust manifolds and didn't want to risk cracking the casts. Anchored and enjoyed the beautiful day for a bit!
Two hours later, I went to start the engine. The crank only turned an inch or so and abruptly stopped. Battery voltage was 14vts so it made me suspicious that something was stopping it from rotating. I decided to start pulling plugs starting with #2. It looked suspiciously wet. #4 was dry and #6 when removed released a stream of uncomfortably hot water (about 1/2 a cup). Never had that happen. Removed #1, 3 and 5 on the other head and they were all dry. Spun the starter and water sprayed out of the #2 and #6 plug holes but seemed to be lessening.
Tucked my tail between my legs and putted back to the dock on the stb engine. Sprayed WD40 into all the cylinders there and spun it again just to try and protect the internals from rust.
I'm thinking Head Gasket or Cracked Head (from overheating) and am ready to pull the boat and start working to remove the "wet head" but decide to go and buy a compression tester first just to see what I'm working with here.
Any ideas???