Getting Your Craftsman M110 Back on the Deck
Most people who own a Craftsman M110 don't realize they're sitting on one of the more repairable mowers ever made by that brand. It's a simple, single-cylinder, 7.5 horsepower Briggs & Stratton setup with a 42-inch cutting deck. The thing falls apart in predictable ways, and knowing which parts are worth replacing yourself versus calling a shop for saves you hundreds. I've spent more Saturday mornings than I care to admit under these machines, swapping blades, adjusting carburetors, and wrestling with stubborn bolts. Here's what actually works when you're trying to figure out whether to buy genuine Craftsman parts, aftermarket replacements, or just move on. Before you order anything, grab the model number decal. It's usually on the frame near the rear axle or on the back of the deck. For the M110, you'll typically see something like 917.276530 or similar variations depending on production year. The engine is almost always a Briggs & Stratton 7.5 HP, model numbers like 12T807 or 13T807, but this varies by production run. Write down both numbers before you start shopping. Here's where most people make mistakes. They order replacement parts based only on the mower model number and end up with something that doesn't fit because Craftsman changed suppliers mid-production run. Always cross-reference with the engine model number too. If you're replacing the carburetor, the engine model matters far more than the mower model. A Briggs & Stratton 12T807 carburetor is not the same as one for a 13T807, even though they share the same HP rating. I learned this the hard way in 2019 when I installed a "perfectly matching" carburetor on a neighbor's M110 and it sat idle for three weeks because the gasket flange was half a millimeter off. The workaround is straightforward: measure the old carburetor mounting holes, check the float bowl shape, and compare the throttle shaft diameter before you order. Online part diagrams from Briggs & Stratton's own website will show you the exact part numbers for your engine variant.
Genuine Craftsman parts come in two flavors now, and this distinction matters. Pre-2017, Craftsman sold parts branded with the red Craftsman logo sourced from various OEM manufacturers. Post-2017, when Sears split from Stanley Black & Decker, the parts situation changed. Newer "genuine" Craftsman parts are often rebranded OEM components from suppliers like Briggs & Stratton, Oregon, or even Chinese manufacturers. The quality is generally consistent because the same factories are making them, but the packaging and markup have shifted. A genuine Craftsman ignition coil for your M110 might cost $45 at a dealership and $28 at an online retailer like PartsTown or ReplacementParts.com, and they could literally be the same coil from the same factory. Aftermarket parts occupy a spectrum from solid to garbage. Let me be specific about what I've found reliable over years of working on these mowers. Oregon blades are worth the extra five dollars. They balance better, hold their edge longer, and the mounting hardware doesn't strip like some budget alternatives. I've replaced blades on the same M110 deck six times over eight years using Oregon 7-inch middle sections with 42-inch outer sections, and they've been consistent. GreenWorks and Ryobi also make acceptable aftermarket blades now, but check the spindle compatibility first. For spark plugs, NGK BM8A or Champion RC12YC are both spec'd for the Briggs & Stratton 7.5 engines in these mowers. Don't cheap out here. A $3 plug will last a full season. A $800 mower won't run right on a $0.50 plug from the gas station. Air filters follow the same pattern. The standard Craftsman part number 491014 or its equivalents from K&N or Briggs own line are all acceptable. I've used oiled K&N filters on my own M110 for four seasons with good results, though you need to clean and re-oil them periodically instead of just throwing them away.
Belts are where aftermarket gets tricky. Gates belts are the gold standard and often what the original equipment came with. They'll cost about $18-22 and last three to five seasons depending on how you maintain the deck. Cheap no-name belts from Amazon or Walmart will crack and delaminate in a single season if you mow during hot summers. The part number for the main drive belt on most M110 models is 144932 or the Gates equivalent 5890. For the deck belt, it's typically 143525 or Gates 5818. Measure your old belt first because there are slight variations between production years. I cut open an old belt and measured the internal cord spacing once to verify I was getting the right replacement, and it saved me from ordering twice. The carburetor rebuild kits are another area where genuine beats aftermarket, but rebuilding is usually cheaper than replacing. The standard rebuild kit for Briggs 12T807/13T807 engines is part number 691058 or the newer 692062. These include the needle valve, seat, gaskets, and primer bulb. I've rebuilt the same carburetor three times on my M110 over twelve years. The key insight most people miss: the main jet rarely needs replacing unless you've been running ethanol-blended fuel without stabilizer. The needle and seat are what wear out, and those are included in the kit. If your mower runs fine at idle but dies under load, clean the main jet with carb cleaner and compressed air before assuming it's bad. I spent two hours tearing into a carburetor once only to find the main jet was barely restricted with gummy residue from old fuel. A five-minute soak in Sea Foam and a blast of compressed air fixed it. Deck spindles and pulleys fail predictably. The spindle assemblies on the M110 are serviceable but not cheap. A genuine Craftsman spindle assembly runs around $60-80 each. Aftermarket versions from Supreme or Oregon copy the design but use different bearing seals. In practice, I've had Supreme spindles last just as long as genuine ones at about 30 percent less cost. The trade-off is availability. Genuine parts come from any Sears Parts Direct or authorized dealer. Supreme spindles require ordering from specialty mower parts sites and waiting 5-7 days for shipping. If your mower is cutting well and you're just doing preventive maintenance, skip the spindle replacement until it actually fails. The bearings in these spindles last a long time if you grease them annually with SAE 30 weight grease through the zerk fitting.
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Here's the practical decision tree I use when a part breaks on the M110. Safety-critical components like the PTO clutch, brake mechanisms, and blade engagement systems should always be genuine or OEM-equivalent. I don't risk aftermarket clutches on these because a failure at 3000 RPM with a spinning blade is not a fun conversation to have. For consumables like spark plugs, air filters, and blades, aftermarket is fine. For things that affect performance like carburetors and ignition coils, genuine or high-quality aftermarket like Bosch or NGK. For structural components like the deck itself, frame brackets, and handle assemblies, genuine is usually the only source anyway because aftermarket copies don't exist for many of these. The online sources I actually use: Sears Parts Direct for genuine parts when I need them today, PartsTown for competitive pricing on Briggs & Stratton components, and Amazon for quick turns on common consumables. eBay is hit or miss but occasionally has NOS (new old stock) parts for older M110 models that are otherwise discontinued. I found a complete set of deck pulleys for a 2003 model on eBay for $15 that Craftsman no longer lists in their catalog. A few edges cases that aren't obvious. The ignition switch on many M110s fails because the internal contacts carbonize from arc flash over years of use. The part is inexpensive, around $25, but Craftsman sometimes lists it as discontinued for older model years. In that case, an aftermarket switch from NAPA or auto parts stores will work if the mounting holes line up. The starter solenoid is another common failure point. The standard replacement is a 12-volt solenoid with 1/4-inch spade terminals and a 5/16-inch bolt for the battery cable. Most automotive aftermarket solenoids will bolt right in. I've used Denso and Bosch automotive solenoids on M110s with perfect results.
Don't overlook the simple stuff. The belt tensioner spring on the M110 is a standard 2-inch diameter, 6-inch long extension spring with 0.177-inch wire. These are available at any hardware store for about $2. If you're replacing a belt and the tensioner spring is broken, don't bother waiting for a specialty parts order. The same spring is used on many lawnmower and snowblower models from different manufacturers. Measure your old spring carefully and match the dimensions. Same goes for the idler pulley bolts. They're typically 5/16-18 x 1 inch cap screws, common hardware store items. One more thing about ordering parts. Keep the old part when you receive the replacement. Compare them side by side before you throw anything away. Manufacturers sometimes change part numbers without changing the physical specifications, and having both lets you verify before you commit to the installation. I once received a replacement ignition coil that looked identical to the old one but had a different resistance value that caused intermittent starting problems. Having both coils side by side let me test them with a multimeter and spot the difference before I installed it on the mower. If you want to go deeper on specific components, the Briggs & Stratton service manual for the 7.5 HP engines covers torque specs, clearance values, and troubleshooting procedures. It's available as a PDF download from Briggs' website or through third-party sources for about $10. The manual will tell you exactly how tight the spindle bolts should be, what gap to set on the ignition coil, and the proper procedure for adjusting the carburetor idle mixture screw. Most people guess at these things and end up with hard starts, rough idle, or damaged components. The manual removes the guesswork.
There's also a growing community around these mowers. Forums like LawnMowerForum and Briggs & Stratton enthusiast boards have decades of documented repairs, part swaps, and improvements from people who've worked on the same engines and decks you're dealing with. Search for your specific model number plus the problem you're having. You'll likely find someone who's already solved it. I found a thread about fixing a recurring oil leak from the crankcase breather on the 12T807 engine that led me to a simple modification: routing the breather tube downward instead of upward to prevent oil from being forced out under pressure. It solved a problem I'd been fighting for two years. The bottom line is that the Craftsman M110 is well-supported by parts availability because it was such a common mower. Most components are standard small-engine parts that haven't changed dramatically in thirty years. The trick is knowing which ones to spend extra on, which ones to source cheaply, and which ones to repair rather than replace. Start with the engine model number, verify part compatibility with measurements and documentation, order from reputable sources, and keep your old parts until you've confirmed the new ones work correctly. That process will save you money, time, and a lot of frustration compared to just grabbing whatever comes up in a search result.
