Heat Transfer cause and prevention

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In the Galveston Bay and surrounding Bay systems the water stays stirred up by Barge traffic and normal Tidal action. This water contains large amounts of sand and silt and also contains living organisms such as algae. This algae is pulled into the cooling systems of marine engines navigating the waterways. Algae prefers a very warm, and wet environment to grow and will attach itself to the insides of cooling systems, preferably in the cylinder heads of Outboard engines right above the combustion chamber where it is nice and warm. The algae seems to prefer the 120 - 140 degree temperature range. If the environment that the algae is in stays warm and wet, the algae will say alive and grow (similar to grass) to a specific length, then will slow down and maintain itself. However, most of the time people aren't using their Boats on a daily basis. This allows the algae to dry up and die. Over hundreds of times of this cycle occurring, the dead algae will build up and over time will cause a heat transfer issue. This layer of dead algae slows the transfer of heat from the metal of the block and heads, to the water that is running through it to keep the engine cool. The result is an engine that will overheat at full throttle or higher RPM's. This problem is found more frequently in Johnson/Evinrude, Yamaha and Force Engines. The problem does not seem to occur in Mercury outboards due to a yellowish green film that is applied to the cooling passages of these engines during the manufacturing process. The repair of this heat transfer issue requires the removal of the cylinder head (s) and a complete cleaning of the cylinder head (s) and block. Alvin Marine offers this service. Please feel free to give us a call or come by and see us today.

Happy Boating!

Author

Ken Wood owner of Alvin Marine LLC is a Factory Trained & Certified Marine Technician with over 30 years in experience in the industry.