Re: Sealant on manifold gasket?
Important Information <br /><br /><br />--------------------------------------------------------------------------------<br /><br />Mercruiser Service Bulletin No. 99-10 transcribed for web posting.<br /><br /><br />Exhaust Manifolds, Risers and Exhaust Elbows<br /><br />Models: All standard V6 and V8 gasoline engines with center outlet exhaust.<br /><br />New Sealant: P/N 92-804874 LOCTITE 510 Sealant - 250 mL Tube.<br /><br />Fastener Torque Change: 33 lb-ft. Use this new torque on all fasteners when<br />installing exhaust elbows or risers onto exhaust manifolds.<br /><br />Assembly: <br />1. Clean all gasket surfaces before reassembly.<br />2. Check the flatness of all gasket surfaces. Maximum overall is .003",<br />with not more than .001" difference within 1".<br /><br />NOTE: Maximum material that can be removed is .010" to true a gasket surface up.<br />When torquing the attaching bolts, make sure that they are not bottoming out in the<br />manifolds threaded hole.<br /><br />3. Look at the condition of the metal around the exhaust outlet casting. Inspect for<br />damaged metal caused by salt water or exhaust gas corrosion in the manifold, elbow<br />and riser (if equipped). Replace all damaged parts.<br /><br /><br />a - Inspect area around exhaust outlet <br /><br /><br />4. Check the fire ring gasket fit on the manifold gasket surface. Place a new gasket on the<br />surface. Thread 4 short 3/8"-16 bolts into the holes. Move the gasket fore and aft,<br />then side to side to make sure the gasket's fire ring has manifold surface under all 4 positions.<br /><br />NOTE: If the gasket's fire ring does not have a solid gasket surface in all 4 positions, the<br />manifold should be replaced.<br /><br /><br />a- Gasket's fire ring has manifold gasket surface under all 4 positions.<br />b- Manifold gasket surface.<br /><br /><br />a- gasket's fire ring does not have enough manifold gasket surface under it.<br />b- Manifold gasket surface.<br /><br /><br />5. There are 3 different types of fire ring gaskets.<br />P/N 27-860323 Gasket with 4 slots.<br />P/N 27-860233 Gasket-Restrictor with 2 holes and 2 slots. The 2 holes in the gasket always<br />go fore and aft.<br />P/N 27-860231 Gasket-Seperator without holes or slots. This gasket stops coolant flow.<br /><br />NOTE: The type of gasket used in certain locations has changed from what is shown in older service literature.<br /><br />1a. Raw water cooled engined with all the water from the thermostat houising going to the 90-degree fitting on the bottom of the exhaust manifold:<br />Use P/N 27-860232 Gasket between the exhaust manifold and the exhaust elbow.<br /><br />If the engine has 3" or 6" risres, use P/N 27-860232 Gasket between the riser and the exhaust manifold and exhaust elbow.<br /><br />1b. Raw water cooled engines with the bypass water forjm the thermostat housing going to<br />the fitting on the exhaust elbow and the warm water from the thermostat housing going to<br />the 90-degree fitting on the bottom of the exhaust manifold:<br /><br />Use P/N 27-860233 Restrictor Gasket between the exhaust manifold and the exhaust elbow.<br /><br />If the engine has 3" or 6" risers, use P/N 27-860233 Restrictor Gasket<br />between the riser and the exhaust elbow. Use P/N 27-860232 Gasket between the exhaust<br />manifold and the riser.<br /><br />2a. Closed cooled engines with the raw water from the heat exchanger going to the 90-degree fitting at the bottom of the manifold:<br /><br />Use P/N 27-860232 Gasket between the exhaust manifold and the exhaust elbow.<br /><br />If the engine has 3" or 6" rises, use P/N 27-860232 Gasket between the riser and the exhaust manifold and exhaust elbow.<br /><br />2b. Closed cooled engines with the exhaust manifolds closed cooled and the raw water<br />from the heat exchanger going to the fitting on the exhaust elbow:<br /><br />Use P/N 27-860231 Seperator Gasket between the exhaust manifold and the exhaust elbow.<br /><br />If the engine is has 3" or 6" risres, use P/N 27-860231 Seperator gasket <br />between the exhaust manifold and the riser. Use P/N 860232 Gasket between the<br />riser and the exhaust elbow.<br /><br />Important: The use of gasket or sealant other than the ones specified in this<br />bulletin are not recommended.<br /><br />6. Apply a 1/8" bead of LOCTITE 510 sealant P/N 92-804874 around all holes on <br />both sides of a new fire ring gasket.<br /><br /><br />a- Apply a 1/8" bead of LOCTITE 510 Sealant <br /><br /><br />7. Assemble parts and torque fasteners to 33 lb-ft.<br /><br />8. Allow sealant to cure for 2-3 hours before starting engine.<br /><br /><br />End of Bulletin<br /><br /><br />--------------------------------------------------------------------------------
