MerCruiser 4 and 6 Cylinder Riser Spacer Block 3 Inch 

Manifold to riser 3" spacer (single block).

Replaces MerCruiser 61851A3.

Fits these applications:

• MerCruiser 4 cylinder 181 C.I.D. 140 H.P., Model 140 engine (log style direct replacement).
• MerCruiser 4 cylinder 153 and 181 C.I.D., 120 H.P. (2.5L) and 140 H.P. (3.0L), Models 120R and 140R-MR/Alpha 1 (log style direct replacement).
• MerCruiser straight 6 cylinder Model 165 (log style direct replacement).

Barr Marine castings have a thicker interior wall, are painted to match original manufacturer colors and are packed in foam for added protection during shipping and storage.

• Includes all mounting hardware, gaskets and drain plug.
• Each spacer block kit includes the spacer block(s) and the corresponding package to mount.

Compatible parts:

• MC-1-52390 direct replacement water cooled exhaust manifold. For serial # 3332138 and up.
• MC-1-58759 direct replacement water cooled manifold to fit the 6 cyl. GM (Model 165) engine.
• MC-1-95862 direct replacement water cooled manifold (Rochester (3 1/4" X 1 7/8") bolt pattern). 6 bolt mounting.
• MC-1-96705 direct replacement water cooled manifold (Rochester (3 1/4" X 1 7/8") bolt pattern). 6 bolt mounting.
• MC-1-99798 direct replacement water cooled manifold (MerCarb (3 11/16" X 2") bolt pattern). 6 bolt mounting.
• MC-20-12076 direct replacement exhaust riser.
• MC-20-60426 direct replacement exhaust elbow riser (utilizes a stainless steel sleeve at the water/air mixing area).
• MC-20-76325 direct replacement exhaust riser.
• MC-20-76351 direct replacement exhaust elbow riser.
• 1-54870 direct replacement exhaust manifold rear end cap. Serial # 4481625 and below.
• 1-54870P rear end cap mounting package.
• 1-60252 direct replacement exhaust manifold end cap/connector.
• 1-60252P front end plate mounting package.
• MC-1-52390P exhaust manifold mounting package.
• MC-1-58759P exhaust manifold mounting package.
• MC-1-58764P manifold to carburetor adaptor mounting package.
• MC-1-99798P exhaust manifold to cylinder head mounting package.
• MC-20-55730 stainless steel fresh water cooling block off plate for use with MerCruiser riser #'s 60426, 76351 and 76771. Requires (2) gaskets part # MC47-27-52076.
• MC-20-60207 stainless steel block off plate (with vent hole) for use with MerCruiser riser #'s 60426, 76351 and 76771. Requires (2) gaskets part # MC47-2752076.
• MC-20-60426P exhaust riser elbow mounting package. For use with both MC-2060426 and MC-20-76351 risers.
• MC-29-47587 direct replacement lower thermostat housing.
• MC-29-60372 direct replacement upper thermostat housing.
• MC47-27-46401 direct replacement manifold to head gasket.
• MC47-27-48043 direct replacement exhaust manifold end cap/connector gasket (will fit both ends).
• MC47-27-52076 direct replacement exhaust elbow to exhaust manifold gasket.
• MC47-27-53354 direct replacement exhaust manifold to cylinder head gasket.
• MC47-27-53354A1 exhaust manifold gasket set.
• MC47-27-73814 direct replacement exhaust manifold end cap gasket. Utilized with 1-73813 rear end cap.
• MC47-27-96429 direct replacement exhaust manifold to cylinder head gasket.
• MC47-27-99777-3 direct replacement exhaust elbow to manifold gasket.

Manufactured by Barr Marine. Part number MC-20-61851A3.