2 Piston Kit & Gasket Set for Briggs 61 Cu In V Twin 841837

Rebuild kit for the Briggs & Stratton 61 cubic inch big block V twin. Two standard piston kits with rings plus the engine gasket set with seals. WHAT IS INCLUDED 2 x 841837 standard piston kit with rings, one per cylinder 1 x 841122 engine gasket set with seals, including the 846037 crankcase gasket NOT INCLUDED - valves. Intake and exhaust valves are separate parts. If the heads are coming off anyway, inspect the valves and guides before ordering so you are not waiting on parts mid job. SPECIFICATION Displacement - 993cc, 61 cubic inches Bore - 3.37 inch, 85.6mm, standard Stroke - 3.41 inch Configuration - OHV V twin MODELS. 611475, 611477, 613477, 61A277, 61A777, 61E177, 61E377, 61E477, 61E777, 61E877 and 61E977. NOT THE 613777. That is the vertical shaft version of the 61 cubic inch big block. The pistons are the same but the engine gasket set is not - it takes 843370 rather than the 841122 supplied here. QUANTITY. Piston kit 841837 covers one cylinder. A V twin needs two, and two are supplied, so one purchase does the whole engine. STANDARD BORE ONLY. The .020 inch oversize piston is 842939 and the matching .020 ring set is 841932. Neither is in this kit. A standard piston in a bored cylinder will not seal and cannot be returned once fitted. THE 54 CUBIC INCH TRAP. The 54 cubic inch big block shares this 3.37 inch bore but runs a 3.07 inch stroke at 896cc, and its piston is 809790. Because the bore is the same, ring sets interchange between the two families - pistons do not. If you only need rings, one ring set covers either displacement and is sold separately. IDENTIFYING YOUR ENGINE. These engines went into riding mowers, zero turns, lawn tractors, generators and log splitters across many equipment makes, so the tag on the machine carries the equipment maker's number rather than the engine's. The model, type and code numbers are stamped on the blower housing. BEFORE ASSEMBLY. Check the bore for taper and glaze, wash out machining grit with hot soapy water, and confirm ring end gap in the bore it will run in.

• WHAT IS IN THE BOX - Two 841837 standard piston kits with rings, which is one per cylinder and what a V twin needs, plus one 841122 engine gasket set with seals. The gasket set carries the 846037 crankcase gasket for the sump joint. Valves are NOT included - if yours are burnt or receded you need intake and exhaust valves on top of this kit, so check them before you order.
• FITS THE 61 CUBIC INCH BIG BLOCK V TWIN - 993cc, bore 3.37 inch or 85.6mm standard, stroke 3.41 inch. Models 611475, 611477, 613477, 61A277, 61A777, 61E177, 61E377, 61E477, 61E777, 61E877 and 61E977. NOT the 613777, which is the vertical shaft version and takes its own gasket set. Read the model number stamped on the blower housing rather than going by the machine it came out of.
• STANDARD SIZE ONLY - These are standard bore pistons. If your cylinders have been cut, the .020 inch oversize piston is 842939 and the .020 ring set is 841932, and neither ships here. A standard piston in an oversize bore will not seal, and once it has been fitted it cannot be returned. Measure, or ask whoever did the machining, before ordering.
• NOT THE 54 CUBIC INCH ENGINE, EVEN THOUGH THE BORE MATCHES - The 54 cubic inch big block runs the same 3.37 inch bore but a shorter 3.07 inch stroke at 896cc, and it takes piston 809790 rather than 841837. Rings interchange between the two families because rings follow the bore. Pistons do not. Getting this wrong is an easy mistake because the bore figure looks identical on paper.
• WHILE THE ENGINE IS APART - Measure the bore for taper before fitting new pistons. Beyond about .003 inch the block wants machining and oversize parts, or it will smoke and pass oil however carefully you assemble it. Wash the cylinders in hot soapy water after any honing to carry the grit out. Check the valves and guides while the heads are off, since that is the job you do not want to do twice.