This Clymer repair and service manual covers 1968-1993 Volvo Stern Drive powerplants, including the following makes and models: VOLVO ENGINES - PUSHROD:

• AQ105A, AQ115A/B, AQ130C/D (4-cylinder)
• AQ165A, AQ170A/B/C (6-cylinder)

VOLVO ENGINES - OVERHEAD CAM:

• AQ120B, AQ125A/B, AQ131A/B/C/D, AQ140A, AQ145A/B, AQ151A/B/C, AQ171A/C, 230, 250, 251 (4-cylinder)

FORD ENGINES:

• 302 V8 (AQ190A)
• 351W V8 (AQ240A)

GENERAL MOTORS ENGINES:

• 229 V6 (AQ175A)
• 262 V6 (AQ205, 430, 431, 432, 434)
• 305 V8 (AQ200C/D/F, AQ211A, AQ225C/D/F, AQ231A, 500, 501)
• 307 V8 (AQ200A/B, AQ225A/B)
• 350 V8 (AQ225A/B, AQ260A, AQ271A/C, AQ280A, AQ290A, AQ311A/B, 570, 571, 572)
• 454 V8 (740)

STERN DRIVE MODELS:

• 200, 250, 270, 275, 280, 290, SP, Duoprop

Book Excerpt: 1968-1993 Volvo Stern Drive Repair Manual VOLVO PUSHROD ENGINES

CYLINDER HEAD | REMOVAL

1. If the engine is in the boat, open the engine block drain valve(s) and allow the water to drain.
2. Remove the intake and exhaust manifolds as described in this chapter.
3. Disconnect all spark plug cables. Remove the spark plugs.
4. Remove the rocker arm cover as described in this chapter.
5. Remove the rocker arm shaft as described in this chapter.
6. Remove the pushrods and identify each for installation in their original position.
7. Remove the timing gear cover as described in this chapter.
8. Loosen the cylinder head bolts, working from the center of the head to the end in each direction.
9. Remove the head bolts (Figure 35).
10. Tap the end of the head with a plastic hammer to break the gasket seal. Remove the head from the engine (Figure 36).
Caution: Place the head on its side to prevent damage to the head gasket surface.
11. Remove and discard the head gasket.

DECARBONIZING

1. Without removing the valves, remove all deposits from the combustion chambers, intake ports and exhaust ports. Use a fine wire brush dipped in solvent or make a scraper from hardwood. Be careful not to scratch or gouge the combustion chambers.
2. After all carbon is removed from the combustion chambers and ports, clean the entire head in solvent.
3. Clean away all carbon on the piston tops. Do not remove the carbon ridge at the top of the cylinder bore.
4. Remove the valves as described in this chapter.
5. Clean pushrod guides, valve guide bores and all bolt holes. Use a cleaning solvent to remove dirt and grease.
6. Clean the valves with a fine wire brush or buffing wheel.

STANDARD COLING SYSTEM

All Volvo marine engines are equipped with a standard cooling system. The water in which the boat is being operated is used as a coolant to absorb engine heat. Water from outside the boat is picked up at the stern drive lower unit intake by a sea water pump located on the front of the engine. The pump forces the sea water through an oil cooler (inline engines, AQ290, AQ311, 571 and 740) and a duct in the exhaust manifold cooling jacket to a distribution housing. The water absorbs the heat created by engine operation and then enters another duct in the exhaust manifold where it mixes with exhaust gases before being expelled from the boat through the exhaust elbow. All 6- and 8-cylinder engines have an engine water pump in addition to the sea water pump. This engine or circulating pump assists in circulating the cooling water through the engine block, head(s) and manifold(s). A thermostat controls water circulation to provide quick engine warmup and maintain a constant operating temperature. Figure 1 (4-cylinder) and Figure 2 (6-cylinder) show typical cooling systems and circulation patterns.

Subject: 1968, 1969, 1970, 1971, 1872, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993 Volvo Stern Drive service, maintenance, repair. ISBN-10: 0892876387 | ISBN-13: 9780892876389