Mercruiser Serpentine Belts, Pulleys, and Kits Service Bulletin 98-1
Models
All V6 and V8 Sterndrive Engines with a Serpentine Belt.
Change
The Power Steering pump pulley material and diameter are changing. The easiest way to tell them apart is by using a magnet near the outer diameter of the pulley.
Before ordering any serpentine belt parts, refer to the chart on the reverse side. Part lists and the Quicksilver Accessories Guide will be revised to show these changes in the future.
V6 and V8 305/350 cid engines: Old pulleys were plastic and 4-3/4 in. (121 mm) in diameter. The new pulley will be metal and 5-3/4 in. (146 mm) in diameter. The plastic power steering pump pulley is going to become NLA. For a replacement pulley for an engine with a plastic pulley, order a Belt/Pulley Kit. A new Belt Kit will be required when installing a Closed Cooling Kit on V6 and V8 305/350 cid Sterndrive engines with the metal 5-3/4 in. (146 mm) pulley.
V8 454/502 cid engines: Old pulleys were plastic and 4-3/4 in. (121 mm) in diameter. The new pulley will be metal and 5-3/4 in. (146 mm) in diameter. The plastic power steering pump pulley is going to become NLA. For a replacement pulley for an engine with a plastic pulley, order a Belt/Pulley Kit.
The new serpentine belts and belt routing diagrams for the high mounted Delco 65A alternator on sterndrive engines have been added to this bulletin. The mounting location of this new Delco 65A alternator did not change on the ski or inboard engines.
| MCM Alpha Models | Part Number | (Belt Route Diagram) Description |
|---|---|---|
| V6 and V8 305/350 cid with plastic P/S pulley. | 57-861758A 1 | (A)-Replacement Belt/Pulley Kit. Contains 5-3/4 in. (146 mm) pulley and longer belt. |
| V6 with plastic P/S pulley and Closed Cooling. | 57-861759A 1 (Note 1) | (B)-Replacement Belt/Pulley Kit. Contains 5-3/4 in. (146 mm) pulley and longer belt. |
| V8 305/350 cid with plastic P/S pulley and Closed Cooling. | 57-861049A 2 (Note 1) | (C)-Replacement Belt/Pulley Kit. Contains 5-3/4 in. (146 mm) pulley and longer belt. |
| V6 with metal 5-3/4 in. (146 mm) P/S pulley. | 807901A 6 (Note 1) | (B)-Order this Belt Kit if a Closed Cooling Kit is going to be installed on the engine. |
| V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley. | 807901A 5 (Note 1) | (C)-Order this Belt Kit if a Closed Cooling Kit is going to be installed on the engine. |
| V6 and V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley. | 807901A 4 | (D)-Order this Belt Kit if P/S pump and hoses are going to be removed on second engine in dual engine boat. |
NOTE 1: Closed Cooling heat exchanger may have to be moved to starboard slightly to clear new, larger pulley.
| MCM Bravo Models | Part Number | (Belt Route Diagram) Description |
|---|---|---|
| V6 and V8 305/350 cid with plastic P/S pulley. | 57-861757A 1 | (E)-Replacement Belt/Pulley Kit. Contains 5-3/4 in. (146 mm) pulley and longer belt. |
| <SPANstyle=”font-family:’sans-serif’, ‘Helvetica’; font-size:11pt; color:#000000″>V6 and V8 305/350 cid with plastic P/S pulley and Closed Cooling. | 57-861049A 2 (Note 1) | (C)-Replacement Belt/Pulley Kit. Contains 5-3/4 in. (146 mm) pulley and longer belt. |
| <SPANstyle=”font-family:’sans-serif’, ‘Helvetica’; font-size:11pt; color:#000000″>V6 and V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley. | 807901A 5 (Note 1) | (C)-Order this Belt Kit if a Closed Cooling Kit is going to be installed on the engine. |
| V6 and V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley. | 807901A 3 (Note 1) | (F)-Order this Belt Kit if P/S pump and hoses are going to be removed on second engine in dual engine boat. |
| V8 454/502 cid with plastic P/S pulley. | 57-861049A 1 (Note 1) | (G)-Replacement Belt/Pulley Kit. Contains 5-3/4 in. (146 mm) pulley and longer belt. |
| V8 454/502 cid with metal 5-3/4 in. (146 mm) P/S pulley. | 57-861050 | (H)-Order this Belt Kit if P/S pump and hoses are going to be removed on second engine in dual engine boat. |
NOTE 1: Closed Cooling heat exchanger may have to be moved to starboard slightly to clear new, larger pulley.
Replacement Belts
| MCM Alpha Models | Belt Route Diagram | Order Part Number |
|---|---|---|
| V6 and V8 305/350 cid with plastic P/S pulley. | A | 57-807755 2 ss 57-861758A 1 |
| V6 with plastic P/S pulley and Closed Cooling. | B | 57-807755 7 |
| V8 305/350 cid with plastic P/S pulley and Closed Cooling. | C | 57-807755 3 ss 57-861049A 2 |
| V6 and V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley | A | 57-861758 |
| B | 57-861759 | |
| V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley and Closed Cooling. | C | 57-861049 |
| V6 and V8 305/350 cid without a P/S pulley, second engine in dual engine boat | D | 57-807755 5 |
| MCM Bravo Models | Belt Route Diagram | Order Part Number |
|---|---|---|
| V6 and V8 305/350 cid with plastic P/S pulley. | E | 57-807755 1 |
| V6 and V8 305/350 cid with plastic P/S pulley and Closed Cooling. | C | 57-807755 3 ss 57-861049A 2 |
| V6 and V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley. | E | 57-861757 |
| V6 and V8 305/350 cid with metal 5-3/4 in. (146 mm) P/S pulley and Closed Cooling. | C | 57-861049 |
| V6 and V8 305/350 cid without a P/S pulley, second engine in dual engine boat | F | 57-807755 4 |
| V8 454/502 cid with plastic P/S pulley. | G | 57-861049 |
| V8 454/502 cid with metal 5-3/4 in. (146 mm) P/S pulley | G | 57-861049 1 |
| V8 454/502 cid without a P/S pulley, second engine in dual engine boat | H | 57-861050 |
| MIE and Ski and Inboard Models | Belt Route Diagram | Order Part Number |
|---|---|---|
| V8 305/350 cid | F | 57-807755 4 |
| V8 454/502 cid | H | 57-861050 |
Belts for V6 and V8 305/350 cid Sterndrive Engines With a High Mounted Delco 65A Alternator
NOTE 1:All ski, inboard and 454/502 cid engines were not affected by the Delco 65A alternator.
| MCM Sterndrive Models | Part Number | (Belt Route Diagram) Description |
|---|---|---|
| V6 and V8 305/350 cid Alpha with P/S pulley. | 57-862086 | (J)-Replacement Belt. |
| V6 and V8 305/350 cid Alpha without P/S pulley | 57-862088 | (K)-Order this Belt if P/S pump and hoses are going to be removed on second engine in dual engine boat. |
| V6 and V8 305/350 cid Bravo with P/S pulley. | 57-862087 | (L)-Replacement Belt. |
| V6 and V8 305/350 cid Bravo without P/S pulley. | 57-862089 | (M)-Order this Belt if P/S pump and hoses are going to be removed on second engine in dual engine boat. |
98-1 JANUARY 2000 Page 5 of 5