headstartnana@aol.com
Seaman Apprentice
- Joined
- Apr 17, 2006
- Messages
- 36
Marine Engine Repair, How to Replace Boat Engines and How to Replace Engine Longblocks<br /><br />** Offering the option between Original Equipment, Direct Replacement, and High Performance OMC Sterndrive engines and Marine Engine Parts ** <br /><br />Topic: 3.0L (120/140) Replace Engine Longblocks<br /><br />Question: How do I replace my damaged longblock with a new or remanufactured product?<br /><br />Response: <br /><br />There are two (2) solutions to this common problem of how to replace boat engines, however, there are many factors affecting the final direction to proceed with. Up through 1991, the engine was produced with a two-piece rear main seal and a 12-3/4" flywheel. Then in 1992, the engine was produced with a single piece rear main seal. Finally in the year 2000, GM upgraded to a 14" flywheel which is how the engines are currently being produced. <br /><br />Solution 1: Marine Engine Repair<br /><br />If your existing engine was built before 1992, you will need a 12-3/4" flywheel that matches the two-piece rear main seal, so that you can re-use your existing coupler and starter. <br />If your engine was built between 1992 & 2000, you can re-use the flywheel on your existing engine. <br />If your engine is not an OMC Cobra engine vintage, it will require that your existing coupler be re-machined to allow it to fit up properly to the 1 pc rear main seal configuration 12-3/4" flywheel. We can help with this as well. <br />If your engine was built after 2000 you can use the flywheel that comes with the new or remanufactured longblocks. We have an option for a 12-3/4" flywheel to go on this engine which is $189. <br />If your engine was a large port engine, or the 120 hp built up until 1994, you will also need the exhaust manifold conversion adapter which converts from the old style oval port head to the higher hp rectangular port head, which is the only head being produced today. <br />Solution 2: Marine Engine Repair<br /><br />Another option is engine conversion kit that can be used with your existing Mercruiser or OMC Cobra/Volvo SX 3.0L engine. These kits include an engine, flywheel, exhaust manifold gasket, fuel pump, and coupler as a complete kit.<br /><br />#301201P_2M - Mercruiser (1968 1990) <br /><br />#301201P_2 OMC Cobra/Volvo SX (1986-1990) <br /><br /> <br /><br />All of this may be confusing but it's about the only option as these blocks are very hard to come by today, and versus remanufactured products having a new longblock is always a better option long term. In our opinion the best quality option is a new 3.0L straight from GM, which has the 14" flywheel.
