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OMC exhaust manifolds and risers problems

Even one bad OMC exhaust manifold can lead to engine over heating problems Check both exhaust manifolds with a water flow testing time Year and horsepower exploded view drawings Please see GLM Marine for the newest OMC manifold parts and the latest updates in manifold conversions on older units not listed here.

By author Trish Dougherty OMC engine manifold failures and heating problems can sometimes be traced to exhaust systems, however before unit is replaced check the water pump flow to the engine. Test is done by testing the time to fill a 2 gallon container at idle speed of 550 rpm to 650 rpm. 50 to 60 seconds for 400-800 stringer series boat years 1968 to 1986. Test time that our mechanics use, note the water pressure should be steady with little or no bubbles. Intermediate housing to water pressure line is one of three lines that need to be checked this way. To ensure water pump flow, clean or replace every 300 to 400 hrs. 51330 Exhaust riser elbow The final product is inspected and machined if needed. All GLM Marine aftermarket cast iron OMC exhaust cooling system products are covered by a 3 year parts and labor warranty. Note 2 years for aluminum manifold or risers. GLM has an up to date web page for availability for certain items. If you do not see your item listed below, please view the GLM list on the manufacturers website. Click image below for individual parts

Exhaust manifold pressure test
51490 back view P/N 51490 Exhaust manifolds and parts for port or starboard side models 5.0, 5.8 and 5.8 liter. 351 OMC King Cobra E.F.I. Ford 302 and 351 C.I.D. with V8 engine. Years 1991 and after 3852347. $337.89	Ford manifold parts 1991 and up P/N 51490 V8 Exhaust manifolds and parts kit for port or starboard sides with 5.0, 5.8 and 5.8 liter 1991 and up for 351 King Cobra E.F.I. Ford 302 and 351 C.I.D. engine. Including: P/N 33790 Manifold gaskets (units of 2) 3852455 P/N 33810 Gasket 3850496 P/N 22486 Studs 2 units 3853434 P/N 21248 Nut (5 units) 3853404 P/N 21754 Screw 3853155 P/N 22290 Cap 4 units 3852476 P/N 01071 Clamp 3852602 May be required but no included: P/N 51330 Riser 1988-1996 with carburetors 3857944 P/N 51332 Riser port side engine 1993-1996 with E.F.I. 3855271. P/N 51334 Riser starboard side 1993-1996 with E.F.I. 3855269 P/N 01090 hose clamp 3852604
51330 OMC Exhaust elbow 5.7 1990 up	P/N 51330 Riser / elbow assembly for both side of engine. Years 1988 to 1996 with carburetor OEM 3857944. $273.99 Includes: P/N 33810 Elbow gasket only 1 unit OEM 3850496
51332 Riser elbow assembly	P/N 51332 Riser / elbow assembly for port side engine. Years 1993 to 1996 with E.F.I. OEM 3855271. $209.09 Includes P/N 33810 Elbow gasket only 1 unit OEM 3850496
51334 Riser elbow assembly	P/N 51334 Riser / elbow assembly for starboard side engine. Years 1993 to 1996 with E.F.I. OEM 3855269. $209.09 Includes P/N 33810 Elbow gasket only 1 unit OEM 3850496
33790 Exhaust manifold gaskets	P/N 33790 Exhaust gaskets set are sold in units of 2 OEM 3852455 $11.00
140 GM 181 cid 3 liter 4 cylinder manifolds	Coming soon P/N 51442 Model 140 GM 181 CID 3.0 liter 4 cylinder 1973 to 1990 assembly with cap and fitting.
OMC 800 and Cobra GM 305-350 CID V8 for years 1979 to 1989 51410 Exhaust manifold for starboard side $261.99 OEM 912441 51420 Aftermarket OMC manifolds for port side	P/N 51410 / P/N 51420 V8 GM 305 / 350 CID V8 CID V8 small block years 1979 to 1989 for both port and starboard sides. Including: 51410 Starboard side 912441 51420 Port side 912442 31100 Gasket 3852468 33810 Gasket (1 unit) 3850496 22280 Cap (1 unit)909830 21791 Clamp 909830 May be required but not included: 22487 Stud 3852467 $8.98 2 (units) 21248 Nut 908700 $4.98 (5 units) 21493 Lock washer 309336 $9.98 (10 units) 51320 Riser / Elbow Assembly 909863 21896 Plug 315713 $7.98 2 (units) 21753 Screw 306435 $4.98 2 (units) 21496 Lock washer 306325 $4.98 2 (units) 89220 Hose (Cobra) 912374 89230 Hose (Cobra) 3852742 $21.98 01090 Clamp 3852604 01200 Clamp 984387 50730 Tube-starboard side (Stringer) 909609 50740 Tube-port side (Stringer) 909610 89221 Hose 909232 89223 Hose 909371
51430 OMC V8-5.7 exhaust manifold 1990 up 51430 OMC Manifold P/N 51430 Manifold assembly for port or starboard side models OEM 3857723 $309.99	Manifold parts 5.7 liter 1990 and up P/N 51430 stern drive model 5.0 to 5.7 liter manifold GM 305-350 CID V8 Years 1989 and after 3857723 Including: P/N 51430 Riser exhaust assembly 3857723 P/N 31100 Gaskets 3852468 P/N 33810 Gasket for elbow 3850496 P/N 22487 Stud (2 units) 3852467 P/N 21248 Flange serrated nuts 3853404 P/N 13982 Straight fitting kit P/N 13992 Drain plug kit P/N 80140 304174 O Ring P/N 13970 fitting 3852538 May be required but not included: P/N 51330 assembly P/N 22316 Screw 3852830 P/N 21493 Lock-washer 3852002 P/N 21675 Washer (5 units) 3852058 P/N 89224 Hose 3852696 P/N 89222 Hose 3852741 P/N 01068 Clamp 3853860 P/N 01090 hose clamp 3852604 P/N 22379 Plug P/N 21896 Plug 315713
OMC V6 1986 to 1990	P/N 51470 / 51472 4.3 and 4.3 H.O. series GM 262 C.I.D. V6 800 series for years OEM 984221 port side and 984222 starboard side 1986 to 1990. Included in exploded view drawing: P/N 51472 Starboard side V6 1986 -1990 assembly with cap and elbow fitting P/N 51470 port side V6 1986 -1990 assembly with cap and elbow fitting P/N 32170 gasket 3853412 P/N 13980 Water drain P/N 13992 Drain plug kit P/N 80140 o rings 304174 P/N 22485 stud 909222 P/N 21248 nut 908700 P/N 21493 Lock-washers 3852002 P/N 13970 fitting 3852538 P/N 89228 hose 912328 P/N 89230 hose 3852742 P/N 01090 clamp 3852604 P/N 01200 clamp 984387
51480 OMC V6 4.3 exhaust manifolds and parts $341.99 V6 1991 and up	P/N 51480 V6 has both side the same. 4.3 liter exhaust assembly Years 1991 and after GM 262 CID V6 3857656. Included in kit: P/N 51480 4.3 Liter V6 1991 and up GM 262 CID exhaust assembly. P/N 32170 #3853412 P/N 33810 #3850496 P/N 22487 Stud (2 units) 3852467 P/N 21248 Nut 3853404 P/N 13982 Straight fitting kit P/N 13992 Drain plug kit P/N 80140 O Ring 304174 P/N 13970 fitting 3852538
OMC Volvo Penta SX manifolds GM 305-350 5.0-5.7 liter years 1989 and up	Volvo Penta Cobra SX P/N 51430 unit 3857944-7 and P/N 51330 Elbow 3857723 both sides same 1994 and up V- 8 GM Small Block
51500 OMC Manifold	P/N 51500 OMC manifold unit for 7.4 liter 454 cubic inch. 8.2 liter 502 cubic inch. V8 Years 1991 and after. Kit includes: P/N 51500 Manifold OEM 3861459 P/N 33810 and drain plug kit. P/N 33760 Gasket OEM 3852472 P/N 33810 Gasket OEM 909786 P/N 13982 Straight fitting P/N 13992 Drain plug kit 22-806608A02-4B P/N 80140 o ring OEM 304174 P/N 13970 Elbow Fitting OEM 3852538
33810 Gasket 39910 Engine manifold gasket set 39790 OMC manifold and riser gasket set 39771 exhaust set 39790 OMC gasket set	Gaskets for 3.0, 3.8, 5.0 or 5.7 liter manifolds Chevy-Ford kits P/N 39910 Years 1975 to 1998 and Volvo 1994 and never. Chevy V8 for 5.0 liter 305 cubic inch, 350 CID 5.7 liter V8 small blocks P/N 39920 Ford V8, 5 liter 302 cubic inch and 5,8 liter, 351 cubic inch small blocks. Years 1977 to 1996 and Volvo years 1994 to 1996. P/N 39770 Chevy large port 4 cylinder 2.5 liter 153 cubic inch, 120 hp. 3.0 liter 181 cubic inch and 140 hp. years 1985 to 1990 P/N 39780 4 cylinder 2.5 liter 153 cubic inch 100 hp. and 120 hp. engine years 1965 to 1985 P/N 39790 Chevy 4 cylinder 140 hp. 3 liter 181 cubic inch and 140 hp. engines years 1973 to 1984 P/N 39800 Ford V8 large block 460 cubic inch 7.5 liter years 1987 to 1990 P/N 39771 GLM marine aftermarket Chevy 4 cylinder, 3.0 liter 181 cubic inch engine 1985 to 1988. Volvo 3.0 liter 1993 and newer P/N 39773 Riser kit for Chevy V6 4.3 liter 262 cubic inch years 1991 to 1998 Volvo years 1992 and newer. P/N 39940 Chevy V8 large block 7.4 liter 454 cubic inch and 8.2 liter 502 cubic inch engines P/N 39776 Ford 4 cylinder 2.3 liter engine years 1987 to 1990 P/N 39774 Chevy V6 4.3 liter 262 cubic inch Volvo engine year 1991 and older P/N 39775 Chevy V8 5.0 liter 305 cubic inch, 5.7 liter 350 cubic inch Volvo engine 1993 and older.
39690 OMC Gasket kit Click here for OMC engine rebuild kit

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