Overhaul Gasket Kit 25-755-37-S Fits Kohler KT17 KT19 M18 M20

Overhaul gasket kit that fits the Kohler KT17, KT19, M18, M20, MV16, MV18 and MV20 twin cylinder engines. Replaces part number 25-755-37-S. WHAT THESE ENGINES ARE. Air cooled, L-head side valve, twin cylinder. The KT prefix is the K-series twin and the M and MV prefix is the series that followed it, and they share the same basic architecture. M means horizontal crankshaft and MV means vertical. KT17, M18 and MV16 are 691cc on a 3.12 by 2.75 inch bore and stroke. KT19, M20 and MV20 are 770cc on a 3.12 by 3.06 inch bore and stroke. WHY THE SPEC NUMBER MATTERS. Four earlier gasket sets - 52-755-10-S, 52-755-92-S, 52-755-93-S and 52-755-94-S - were consolidated into this one number across a long production run. Dealers list it as fitting some engines in a model range rather than all of them. The spec number is on the blower housing decal beside the model number, and it is what the parts catalog keys on. Read both before ordering. NOT FOR THE SINGLE CYLINDER ENGINES. The M8, M10, M12, M14 and M16 are single cylinder engines and take different gaskets. M16 and MV16 are not the same engine, which is the easiest mistake to make on this family. CRANKSHAFT SEALS, AND WHY THEY MATTER. The kit includes crankshaft seals. A hardened seal draws air past it and leans the mixture out, and the symptom on these engines is an idle that will not come down or a motor that revs and hangs. That gets chased at the carburetor for a long time before anyone pressure tests the crankcase. If the engine is open far enough to need gaskets, the seals are worth doing at the same time. ON ASSEMBLY. Clean every sealing face back to bare metal, check the cylinder heads for warp on a flat surface before they go back on, and torque in the factory sequence in stages rather than in one pass.

• FITS KOHLER KT17, KT19, M18, M20, MV16, MV18 AND MV20 TWINS - Overhaul gasket kit with crankshaft seals. Replaces 25-755-37-S, the factory overhaul kit number that consolidated the earlier 52-755-10-S, 52-755-92-S, 52-755-93-S and 52-755-94-S sets.
• CHECK THE SPEC NUMBER, NOT JUST THE MODEL - These engines were built across a long run and rolled four earlier gasket sets into this one number. The spec number is stamped on the blower housing decal next to the model, and it is what the parts catalog actually keys on. Read both before you order.
• TWIN CYLINDER L-HEAD ONLY - NOT THE SINGLES - The KT, M and MV twins covered here are 691cc or 770cc depending on model: KT17, M18 and MV16 are 691cc, KT19, M20 and MV20 are 770cc. The single cylinder M8, M10, M12, M14 and M16 are a different engine and take different gaskets. M16 and MV16 are not the same engine.
• A HARDENED CRANKSHAFT SEAL READS LIKE A CARBURETOR FAULT - Air drawn past a crankshaft seal leans the mixture, and the symptom is an idle that will not come down or an engine that revs and hangs. It gets chased at the carburetor for weeks before anyone pressure tests the crankcase. Both seals are in this kit, so do them while the engine is open.
• WHAT TO DO WHILE YOU ARE IN THERE - Clean the sealing faces back to bare metal rather than fighting old gasket with the engine assembled, check the cylinder head for warp on a flat surface before it goes back on, and torque in sequence and in stages. Ethanol hardens gasket material, so a set sitting in a machine run on pump fuel is usually overdue.