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Kohler K-Series and Magnum Single Cylinder Engine Specifications and Tolerances
(All dimensions in inches.)

Model (Horsepower @ 3,600 rpm)				K90 / K91 (4hp @ 4,000 rpm)	K141 (early) (6.6hp) K161 (late) (7hp)	K181 (8hp)	K241 (10hp)	K301 (12hp)	K321 (14hp)	K341 (16hp)	K361 (18hp) (Over Head Valve)
General	Bore x Stroke			STD. 2.375" .010" 2.385" .020" 2.395" .030" 2.405" x 2.000"	2.875"(early) STD.2.938"(late) .010" 2.948" .020" 2.958" .030" 2.968" x 2.500"	STD. 2.938" .010" 2.948" .020" 2.958" .030" 2.968" x 2.750"	STD. 3.251" .010" 3.261" .020" 3.271" .030" 3.281" x 2.875"	STD. 3.375" .010" 3.385" .020" 3.395" .030" 3.405" x 3.250"	STD. 3.500" .010" 3.510" .020" 3.520" .030" 3.530" x 3.250"	STD. 3.750" .010" 3.760" .020" 3.770" .030" 3.780" x 3.250"	STD. 3.750" .010" 3.760" .020" 3.770" .030" 3.780" x 3.250"
	Cubic Inch Displacement (STD bore)			8.86	16.22 / 16.95	18.64	23.85	29.07	31.27	35.90	35.90
	Compression Ratio			?	?	?	7.1:1, 5.4:1 or 5:1 (See note 8)	8.6:1, 6.6:1 or 6.1:1 (See note 8)	6.6:1, 7:1 or 9:1 (See note 8)	7.4:1	9.2:1
	Operating RPM (maximum)			4,000	3,600	3,600	3,600	3,600	3,600	3,600	3,600
Balance Gear	Shaft O.D.	New		-	-	-	.4998" (min.) .5001" (max.)	.4998" (min.) .5001" (max.)	.4998" (min.) .5001" (max.)	.4998" (min.) .5001" (max.)	.4998" (min.) .5001" (max.)
		Wear Limit (maximum)		-	-	-	.4996"	.4996"	.4996"	.4996"	.4996"
	End Play			-	-	-	.002" (min.) .010" (max.)	.002" (min.) .010" (maz.)	.002" (min.) .010" (max.)	.002" (min.) .010" (max.)	.002" (min.) .010" (max.)
Camshaft	End Play			.005" (min.) .020" (max.)	.005" (min.) .010" (max.)	.005" (min.) .010" (max.)	.005" (min.) .010" (max.)	.005" (min.) .010" (max.)	.005" (min.) .010" (max.)	.005" (min.) .010" (max.)	.005" (min.) .010" (max.)
Connecting Rod	Running Clearance		Big End Diameter (maximum)	.938" (STD)	STD. 1.1875" .010" 1.1975"	STD. 1.1875" .010" 1.1975"	STD. 1.5015" .010" 1.5115" .020" 1.5215" .030" 1.5315"	STD. 1.5015" .010" 1.5115" .020" 1.5215" .030" 1.5315"	STD. 1.5015" .010" 1.5115" .020" 1.5215" .030" 1.5315"	STD. 1.5015" .010" 1.5115" .020" 1.5215" .030" 1.5315"	STD. 1.5015" .010" 1.5115" .020" 1.5215" .030" 1.5315"
			Rod to Crankpin	.001" (min.) .0025" (max.)	.001" (min.) .002" (max.)	.001" (min.) .002" (max.)	.001" (min.) .002" (max.)	.001" (min.) .002" (max.)	.001" (min.) .002" (max.)	.001" (min.) .002" (max.)	.001" (min.) .002" (max.)
			Rod to Crankpin Wear Limit (maximum)	.003"	.0025"	.0025"	.0025"	.0025"	.0025"	.0025"	.0025"
			Rod to Piston Pin	.0007" (mim.) .0008" (max.)	.0006" (min.) .0011" (max.)	.0006" (min.) .0011" (max.)	.0003" (min.) .0008" (max.)	.0003" (min.) .0008" (max.)	.0003" (min.) .0008" (max.)	.0003" (min.) .0008" (max.)	.0003" (min.) .0008" (max.)
	Small End I.D.			.5630" (min.) .5633" (max.)	.6255" (min.) .6258" (max.)	.6255" (min.) .6258" (max.)	.8596" (min.) .8599" (max.)	.8757" (min.) .8760" (max.)	.8757" (min.) .8760" (max.)	.8757" (min.) .8760" (max.)	.8757" (min.) .8760" (max.)
Crankshaft	Main PTO and Flywheel End O.D.		New (max.)	.9844"	1.1814"	1.1814"	1.5749"	1.5749"	1.5749"	1.5749"	1.5749"
			Wear Limit (maximum)	.9841"	1.1811"	1.1811"	1.5745"	1.5745"	1.5745"	1.5745"	1.5745"
	Crankpin	New		.9355" (std) .9360" (max.)	1.1855" (std) 1.1860" (max.)	1.1855" (std) 1.1860" (max.)	1.4995" (std) 1.5000" (max.)	1.4995" (std) 1.5000" (max.)	1.4995" (std) 1.5000" (max.)	1.4995" (std) 1.5000" (max.)	1.4995" (std) 1.5000" (max.)
		Wear Limit (maximum)		.9350"	1.1850"	1.1850"	1.4990"	1.4990"	1.4990"	1.4990"	1.4990"
		Out of Round (maximum)		.0005"	.0005"	.0005"	.0005"	.0005"	.0005"	.0005"	.0005"
		Taper (max.)		.001"	.001"	.001"	.001"	.001"	.001"	.001"	.001"
	End Play			.004" (min.) .023" (max.)	.002" (min.) .023" (max.)	.002" (min.) .023" (max.)	.003" (min.) .020" (max.)	.003" (min.) .020" (max.)	.003" (min.) .020" (max.)	.003" (min.) .020" (max.)	.003" (min.) .020" (max.)
Cylinder Bore	Inside Diameter		New	2.3745" (std) 2.3755" (max.)	2.9370" (std) 2.9380" (maz.)	2.9370" (std) 2.9380" (maz.)	3.2505" (std) 3.2515" (max.)	3.3745" (std) 3.3755" (max.)	3.4995" (std) 3.5005" (max.)	3.7495" (std) 3.7505" (max.)	3.7495" (std) 3.7505" (max.)
			Maximum Wear Limit	2.378"	2.941"	2.941"	3.254"	3.378"	3.503"	3.753"	3.753"
	Maximum Out of Round			.003"	.003"	.003"	.003"	.003"	.003"	.003"	.003"
	Maximum Taper			.003"	.003"	.003"	.002"	.002"	.002"	.002"	.002"
Cylinder Head	Maximum Out of Flatness			.003"	.003"	.003"	.003"	.003"	.003"	.003"	.003"
Ignition	Spark Plug - Type and Gap		Type (See note 2)	RCJ-8	RCJ-8	RCJ-8	RH-10	RH-10	RH-10	RH-10	RH-10
			Battery	.035"	.035"	.035"	.035"	.035"	.035"	.035"	.035"
			Magneto	.025"	.025"	.025"	.025"	.025"	.025"	.025"	.025"
			LP/Propane	.018"	.018"	.018"	.018"	.018"	.018"	.018"	.018"
	Nominal Point Gap or Mark on Flywheel / Degrees BTDC			.020" or S mark at 20º	.020" or S mark at 20º	.020" or S mark at 20º	.020" or S mark at 20º	.020" or S mark at 20º	.020" or S mark at 20º	.020" or S mark at 20º	.020" or S mark at 20º
Model (Horsepower)				K90 (early) K91 (late) (4)	K141 (early) K161 (late) (7)	K181 (8)	K241 (10)	K301 (12)	K321 (14)	K341 (16)	K361 (18) (Over Head Valve)
All Pistons	Service Replacement Sizes			ß .003" - .010" - .020" - .030" à
	Thrust Face O.D. (See note 3)		New	2.371"/2.369"	2.9297"/2.9281"	2.9297"/2.9281"	3.2432"/3.2413"	3.368"/3.365"	3.4941"/3.4925"	3.7425"/3.7410"	3.7425"/3.7410"
			Maximum Wear Limits	2.366"	2.925"	2.925"	3.238"	3.363"	3.491"	3.738"	3.738"
	Thrust Face to Bore Clearance (max.) (1)			.0035"/.006"	.007"/.010"	.007"/.010"	.007"/.010"	.007"/.010"	.007"/.010"	.007"/.010"	.007"/.010"
	Ring End Gap		New Bore	.007"/.017"	.007"/.017"	.007"/.017"	.010"/.020"	.010"/.020"	.010"/.020"	.010"/.020"	.010"/.020"
			Used Bore (Maximum)	.027"	.027"	.027"	.030"	.030"	.030"	.030"	.030"
	Maximum Ring Side Clearance			.006"	.006"	.006"	.006"	.006"	.006"	.006"	.006"
	Thrust Face O.D. (See note 5)		New	-	-	-	-	-	-	3.7465"/3.7455"	3.7465"/3.7455"
			Maximum Wear Limits	-	-	-	-	-	-	3.744	3.744
	Thrust Face to Bore Clearance (max.) (See note 1)			-	-	-	-	-	-	.0030"/.0050"	.0030"/.0050"
	Ring End Gap		New Bore (See note 6)	-	-	-	-	-	-	.010"/.020"	.010"/.020"
			Used Bore (Maximum) (See note 6)	-	-	-	-	-	-	.030"	.030"
	Maximum Ring Side Clearance			-	-	-	-	-	-	.004"	.004"
	Thrust Face O.D. (See note 5)		New / Used	-	-	2.9329" (min.) 2.9336" (max.)	-	3.3700" (min.) 3.3693" (max.)	3.4945" (min.) 3.4938" (max.)	3.7433"/3.7426"	3.7433"/3.7426"
			Maximum Wear Limits	-	-	2.931"	-	3.367"	3.492"	3.7406"	3.7406"
	Thrust Face to Bore Clearance (max.) (See note 1)			-	-	.0034" (min.) .0051" (max.)	-	.0045" (min.) .0062" (max.)	.0050" (min.) .0067" (max.)	.0062" (min.) .0079" (max.)	.0062" (min.) .0079" (max.)
	Ring End Gap		New Bore (See note 6)	-	-	.010"/.023"	-	.010"/.020"	.010"/.020"	.013"/.025"	.013"/.025"
			Used Bore (Maximum) (See note 6)	-	-	.032"	-	.030"	.030"	.033"	.033"
	Maximum Ring Side Clearance			-	-	.006"	-	.006"	.006"	.004"	.004"
	Piston Pin Outside Diameter			.5623" (min.) .5625" (max.)	.6247" (used .6249" (max.)	.6247" (min.) .6249" (max.)	.8591" (min.) .8593" (max.)	.8752" (min.) .8754" (max.)	.8752" (min.) .8754" (max.)	.8752" (min.) .8754" (max.)	.8752" (min.) .8754" (max.)
Model (Horsepower)				K90 (early) K91 (late) (4)	K141 (early) K161 (late) (7)	K181 (8)	K241 (10)	K301 (12)	K321 (14)	K341 (16)	K361 (18) (Over Head Valve)
Valves	Valve Head Diameter			?	1-3/8" intake 1-1/8" exhaust	1-3/8" intake 1-1/8" exhaust	1-3/8" intake 1-1/8" exhaust	1-3/8" intake 1-1/8" exhaust	1-3/8" intake 1-1/8" (early)/ 1-3/8" (late) exhaust	1.3/8" intake 1-3/8" exhaust	1.3/8" intake 1-3/8" exhaust
	Guide Reamer Size			.250"	.3125"	.3125"	.3125"	.3125"	.3125"	.3125"	.3125"
	Tappet Clearance (Cold)		Intake	.005" (min.) .009" (max.)	.006" (min.) .008" (max.)	.006" (min.) .008" (max.)	.008" (min.) .010" (max.)	.008" (min.) .010" (max.)	.008" (min.) .010" (max.)	.008" (min.) .010" (max.) (See note 4)	.008" (min.) .010" (max.) (See note 4)
			Exhaust	.011" (min.) .015" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)
	Minimum Lift (Zero Lash)		Intake	.2035"	.2718"	.2718"	.318"	.318"	.318"	.318"	.318"
			Exhaust	.1768"	.2482"	.2482"	.318"	.318"	.318"	.318"	.318"
	Minimum Stem O.D.		Intake	.2478"	.3103"	.3103"	.3103"	.3103"	.3103"	.3103"	.3103"
			Exhaust	.2458"	.3088"	.3088"	.3074"	.3074"	.3074"	.3074"	.3074"
	Face Angle - Seat Angle -			45º 46º	45º 46º	45º 46º	45º 46º	45º 46º	45º 46º	45º 46º	45º 46º
	Guide I.D. Maximum Wear Limit (See note 1)		Intake	.005"	.005"	.005"	.006"	.006"	.006"	.006"	.006"
			Exhaust	.007"	.007"	.007"	.008"	.008"	.008"	.008"	.008"
			Lifter to Bore Clearance (note 5)	.001" - .0015"	.001" - .0015"	.001" - .0015"	.001" - .0015"	.001" - .0015"	.001" - .0015"	.001" - .0015"	.001" - .0015"

NOTES

Note 1 - Subtract O.D. of inner part from I.D. of outer part. Note 2 - Champion spark plugs or equivalent. Note 3 - Measure just below oil ring groove and at right angles to piston pin. Note 4 - 1,800 RPM generator sets .005/ 007. Note 5 - If you feel you need to have the lifter bores in your block reamed for installation of bronze bushings, just like the valves, the lifters are offset at a 4 degree angle.

Note 5 - Measure 1/2" above the bottom of the piston skirt. Note 6 - Top and center compression rings. Note 7 - Measure just below oil ring groove and at right angles to piston pin. Note 8 - Compression ratio depends on which type of cylinder head is used.

Magnum - Single Cylinder Engine Specifications and Tolerances
All dimensions in inches.

Model (Horsepower)			M8 (8)	M10 (10)	M12 (12)	M14 (14)	M16 (16)
General	Bore x Stroke		2.94" x 2.75"	3.25" x 2.88"	3.38" x 3.25"	3.50" x 3.25"	3.75" x 3.25"
	Displacement Cu. In.		18.64	23.85	29.07	31.27	35.90
	Operating RPM (maximum)		3,600	3,600	3,600	3,600	3,600
Balance Gear	Shaft O.D.	New	-	.4998"/.5001"	.4998"/.5001"	.4998"/.5001"	.4998"/.5001"
		Maximum Wear Limit	-	.4996"	.4996"	.4996"	.4996"
	End Play		-	.002"/.010"	.002"/.010"	.002"/.010"	.002"/.010"
Camshaft	End Play		.005"/.010"	.005"/.010"	.005"/.010"	.005"/.010"	.005"/.010"
Connecting Rod	Running Clearance	Maximum Big End Diameter	1.1875" (STD)	1.5015" (STD)	1.5015" (STD)	1.5015" (STD)	1.5015" (STD)
		Rod to Crankpin (max.)	.001"/.002"	.001"/.002"	.001"/.002"	.001"/.002"	.001"/.002"
		Rod to Crankpin - Maximum Wear Limit	.0025"	.0025"	.0025"	.0025"	.0025"
		Rod to Piston Pin (max.)	.0006"/.0011"	.0003"/.0008"	.0003"/.0008"	.0003"/.0008"	.0003"/.0008"
	Small End I.D. (max.)		.6255"/.6258"	.8596"/.8599"	.8757"/.8760"	.8757"/.8760"	.8757"/.8760"
Crankshaft	Main PTO & Flywheel End O.D.	New	1.1811"/1.1814"	1.5745"/1.5749"	1.5745"/1.5749"	1.5745"/1.5749"	1.5745"/1.5749"
		Maximum Wear Limit	1.1811"	1.5745"	1.5745"	1.5745"	1.5745"
	Crankpin	New - O.D.	1.1860"/1.1855"	1.5000"/1.4995"	1.5000"/1.4995"	1.5000"/1.4995"	1.5000"/1.4995"
		Maximum Wear Limit	1.1850"	1.4990"	1.4990"	1.4990"	1.4990"
		Maximum Out of Round	.0005"	.0005"	.0005"	.0005"	.0005"
		Maximum Taper	.001"	.001"	.001"	.001"	.001"
	End Play		.002"/.023"	.003"/.020"	.003"/.020"	.003"/.020"	.003"/.020"
Cylinder Bore	Inside Diameter	New	2.9380"/2.9370"	3.2515"/3.2505"	3.3755"/3.3745"	3.5005"/3.4995"	3.7505"/3.7495"
		Maximum Wear Limit	2.941"	3.254"	3.378"	3.503"	3.753"
	Maximum Out of Round (I.D.)		.005"	.005"	.005"	.005"	.005"
	Maximum Taper (I.D.)		.003"	.002"	.002"	.002"	.002"
Cylinder Head		Maximum Out of Flatness	.003"	.003"	.003"	.003"	.003"
Ignition (Solid State)	Spark Plug	Type (note 2)	RCJ-8	RH-10	RH-10	RH-10	RH-10
		Gap	.025"	.025"	.025"	.025"	.025"
	Module Air Gap		.012"/.016"	.012"/.016"	.012"/.016"	.012"/.016"	.012"/.016"
Model (Horsepower)			M8 (8)	M10 (10)	M12 (12)	M14 (16)	M16 (16)
All Pistons	Service Replacement Sizes		ß .003" - .010" - .020" - .030" à
	Thrust Face O.D. (note3)	New	2.9297"/2.9281	3.2432"/3.2413	3.368"/3.365	3.4941"/3.4925	-
		Maximum Wear Limits	2.925"	3.238"	3.363"	3.491"	-
	Thrust Face to Bore Clearance (max.) (note 1)		.007"/.010"	.007"/.010"	.007"/.010"	.007"/.010"	-
	Ring End Gap	New Bore	.007"/.017"	.010"/020"	.010"/.020"	.010"/.020"	-
		Used Bore (Maximum)	.027"	.030"	.030"	.030"	-
	Maximum Ring Side Clearance		.006"	.006"	.006"	.006"	-
	Thrust Face O.D. (note 4)	New	-	-	-	-	3.7465"/3.7455"
		Maximum Wear Limits	-	-	-	-	3.7435"
	Thrust Face to Bore Clearance (max.) (note 1)		-	-	-	-	.0030"/.0050"
	Ring End Gap	New Bore (note 5)	-	-	-	-	.010"/020"
		Used Bore (Maximum) (note 5)	-	-	-	-	.030
	Maximum Ring side Clearance		-	-	-	-	.004"
	Thrust Face O.D. (note 4)	New	2.9329"/2.9336"	-	3.3700"/3.3693"	3.4945"/3.4938"	3.7433"/3.7426"
		Maximum Wear Limits	2.9312"	-	3.3673"	3.4918"	3.7406"
	Thrust Face to Bore Clearance (max.) (note 1)		.0034"/.0051"	-	.0045"/.0062"	.0050"/0067"	.0062"/.0079"
	Ring End Gap	New Bore (note 5)	.010"/.023"	-	.010"/.020"	.010"/.020"	.013"/.025"
		Used Bore (Maximum) (note 5)	.032"	-	.030"	.030"	.033"
	Maximum Ring Side Clearance		.006	-	.006	.006	.004
Piston Pin	Outside Diameter		.6247" (min.) .6249" (max.)	.8591" (min.) .8593" (max.)	.8752" (min.) .8754" (max.)	.8752" (min.) .8754" (max.)	.8752" (min.) .8754" (max.)
Valves	Valve Head Diameter		1-3/8" intake 1-1/8" exhaust	1-3/8" intake 1-1/8" exhaust	1-3/8" intake 1-1/8" exhaust	1-3/8" intake 1-3/8" exhaust	1.3/8" intake 1-3/8" exhaust
	Guide Reamer Size		.3125"	.3125"	.3125"	.3125"	.3125"
	Tappet Clearance (Cold)	Intake	.006" (min.) .008" (max.)	.008" (min.) .010" (max.)	.008" (min.) .010" (max.)	.008" (min.) .010" (max.)	.008" (min.) .010" (max.)
		Exhaust	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)	.017" (min.) .019" (max.)
	Minimum Lift (Zero Lash)	Intake	.2718"	.318"	.318"	.318"	.318"
		Exhaust	.2482"	.318"	.318"	.318"	.318"
	Minimum Stem O.D.	Intake	.3103"	.3103"	.3103"	.3103"	.3103"
		Exhaust	.3074"	.3074"	.3074"	.3074"	.3074"
	Face Angle - Seat Angle -		45º 46º	45º 46º	45º 46º	45º 46º	45º 46º
	Guide I.D. Maximum Wear Limit (note 1)	Intake	.006"	.006"	.006"	.006"	.006"
		Exhaust	.008"	.008"	.008"	.008"	.008"
		Lifter to Bore Clearance (note 6)	.001" - .0015"	.001" - .0015"	.001" - .0015"	.001" - .0015"	.001" - .0015"

Note 1 - Subtract O.D. of inner part from I.D. of outer part.
Note 2 - Champion spark plugs or equivalent.
Note 3 - Measure just below oil ring and at right angles to piston pin.
Note 4 - Measure 1/2" above the bottom of the piston skirt.
Note 5 - Top and center compression rings.
Note 6 - If you feel you need to have the lifter bores in your block reamed for installation of bronze bushings, just like the valves, the lifters are offset at a 4 degree angle.

Kohler K-Series - Single Cylinder Torque Values and Sequences for Fasteners | Top of page

Model (Horsepower)		K91 (4)	K161 (7)	K181 (8)	K241 (10), K301 (12), K321 (14), K341 (16) and K361 (18)
Connecting Rods (See notes 1 & 2)	Posi-Lock (nut)	-	-	New 140 in. lb./12 ft. lb. Used 100 in. lb./9 ft. lb.	New 260 in. lb./22 ft. lb. Used 200 in. lb./17 ft. lb.
	Capscrew (bolt)	140 in. lb./12 ft. lb.	200 in. lb./17 ft. lb.		285 in. lb./24 ft. lb.
Spark Plugs		234 in. lb./18-22 ft. lb	234 in. lb./18-22 ft. lb.		234 in. lb./18-22 ft. lb
Cylinder Head (See note 1)
Flywheel Retaining (See note 5)	Nut (See note 1)	40-50 ft. lb.	85-90 ft. lb. note 4		5/8" stud - 65 ft. lb. 3/4" stud - 170 ft. lb.
	Screw (3/8" bolt) (See note 1)	250 in. lb.	-		22-27 ft. lb./35 ft. lb.
Governor Bushing		70-90 in. lb.	130-150 in. lb.		100-120 in. lb.
Grass Screen	Metal	-	70-140 in. lb.		70-140 in. lb.
	Plastic	-	-		20-30 in. lb.
Oil Pan	Cast Iron (see note 1)	250 in. lb.	Grade 5-250 in. lb. Grade 8-350 in. lb.		35 ft. lb.
	Sheet Metal (See note 1)	-	-		200 in. lb.
Plastic Fuel Pump Mounting Screws		-	37-45 in. lb.		37-45 in. lb.

Note 1 - Lubricate fastener threads with engine oil.
Note 2 - DO NOT overtorque - DO NOT loosen and retorque the hex. nuts on Posi-Lock connecting rods.
Note 3 - Overtorque 20%, loosen below torque value and retorque to final torque value. NOTE: Overtorquing the rod bolts 20% places stress on the threads in a NEW aluminum rod. This allows for proper tightness so the bolts won't loosen later. Torque used rods to 285 in. lbs. and leave them at that.
Note 4 - Prior to Serial No. 23209832 - 45-55 ft. lb.
Note 5 - Flywheel and crankshaft tapers must be clean and dry.
NEW - Component directly from stock. USED - Component that was in a running engine.

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